Knowledge Base : Tutorials : Battery Articles : Battery Basics: A Layman's Guide to BatteriesBattery Basics: A Layman's Guide to Batteries

If you have done any research on how batteries work or what you should look for when selecting a battery, you are probablyburied in information, some of which is conflicting. At BatteryStuff, we aim to clear that up a bit.You have most likely heard theterm K.I.S.S. (Keep It Simple, Stupid). I am going to attempt to explain how lead acid batteries work and what they needwithout burying you with a bunch of needless technical data. I have found that battery data will vary somewhat frommanufacturer to manufacturer, so I will do my best to boil that data down. This means I may generalize a bit, while staying trueto purpose.

The commercial use of the lead acid battery is over 100 years old. The same chemical principal that is being used to storeenergy is basically the same as our Great Grandparents may have used.

If you can grasp the basics you will have fewer battery problems and will gain greater battery performance, reliability, andlongevity. I suggest you read the entire tutorial, however I have indexed all the information for a quick read and easy reference.

A battery is like a piggy bank. If you keep taking out and putting nothing back you soon will have nothing. Present day chassisbattery power requirements are huge. Consider today’s vehicle and all the electrical devices that must be supplied. All theseelectronics require a source of reliable power, and poor battery condition can cause expensive electronic component failure.Did you know that the average auto has 11 pounds of wire in the electrical system? Look at RVs and boats with all the electricalgadgets that require power. It was not long ago when trailers or motor homes had only a single 12-volt house battery. Today it isstandard to have two or more house batteries powering inverters up to 4000 watts.

Average battery life has become shorter as energy requirements have increased. Life span depends on usage; 6 months to 48months, yet only 30% of all batteries actually reach the 48-month mark. You can extend your battery life by hooking it up to asolar charger during the off months.A Few Basics

The Lead Acid battery is made up of plates, lead, and lead oxide (various other elements are used to change density,hardness, porosity, etc.) with a 35% sulfuric acid and 65% water solution. This solution is called electrolyte, which causes achemical reaction that produce electrons. When you test a battery with a hydrometer, you are measuring the amount of sulfuricacid in the electrolyte. If your reading is low, that means the chemistry that makes electrons is lacking. So where did the sulfurgo? It is resting on the battery plates and when you recharge the battery, the sulfur returns to the electrolyte.SafetyBattery types, Deep Cycle and StartingWet Cell, Gel-Cell and Absorbed Glass Mat (AGM)CCA, CA, AH and RC; what's that all about?Battery MaintenanceBattery TestingSelecting and Buying a New BatteryBattery Life and PerformanceBattery ChargingBattery Do'sBattery Don'ts

1. We must think safety when we are working around and with batteries. Remove all jewelry. After all you don't want to meltyour watchband while you are wearing the watch. The hydrogen gas that batteries make when charging is very explosive. Wehave seen several instances of batteries blowing up and drenching everything in sulfuric acid. That is no fun, and would havebeen a good time to use those safety goggles that are hanging on the wall. Heck, just break out your disco outfit. Polyester is notaffected by Sulfuric Acid, but anything with cotton will be eaten up. If you do not feel the need to make a fashion statementjust wear junk clothes, after all Polyester is still out of style. When doing electrical work on vehicles it is best to disconnect theground cable. Just remember you are messing with corrosive acid, explosive gases and 100's amps of electrical current.

2. Basically there are two types of lead acid batteries (along with 3 sub categories); The two main types are Starting(cranking), and Deep Cycle (marine/golf cart). The starting battery (SLI starting lights ignition) is designed to deliver quickbursts of energy (such as starting engines) and therefore has a greater plate count. The plates are thinner and have somewhatdifferent material composition. The deep cycle battery has less instant energy, but greater long-term energy delivery. Deepcycle batteries have thicker plates and can survive a number of discharge cycles. Starting batteries should not be used for deepcycle applications because the thinner plates are more prone to warping and pitting when discharged. The so-called DualPurpose Battery is a compromise between the two types of batteries, though it is better to be more specific if possible.

3. Wet Cell (flooded), Gel Cell, and Absorbed Glass Mat (AGM) are various versions of the lead acid battery. The Wet cellcomes in two styles; Serviceable and Maintenance free. Both are filled with electrolyte and are basically the same. I prefer onethat I can add water to and check the specific gravity of the electrolyte with a hydrometer. The Gel Cell and the AGMbatteries are specialty batteries that typically cost twice as much as a premium wet cell. However they store very well and donot tend to sulfate or degrade as easily as wet cell. There is little chance of a hydrogen gas explosion or corrosion when usingthese batteries; these are the safest lead acid batteries you can use. Gel Cell and some AGM batteries may require a specialcharging rate. If you want the best,most versatile type, consideration should be given to the AGM battery for applications suchas Marine, RV, Solar, Audio, Power Sports and Stand-By Power just to name a few. If you don't use or operate your equipmentdaily, AGM batteries will hold their charge better that other types. If you must depend on top-notch battery performance, spendthe extra money. Gel Cell batteries still are being sold but AGM batteries are replacing them in most applications. There is asome common confusion regarding AGM batteries because different manufactures call them by different names; some of themore common names are "sealed regulated valve", "dry cell", "non spillable", and "Valve Regulated Lead Acid" batteries. Inmost cases AGM batteries will give greater life span and greater cycle life than a wet cell battery.SPECIAL NOTE about Gel Batteries: It is very common for individuals to use the term GEL CELL when referring to sealed,maintenance free batteries, much like one would use Kleenex when referring to facial tissue or "Xerox machine" when referringto a copy machine. Be very careful when specifying a gel cell battery charger, many times we are told by customer they arerequiring a charger for a Gel Cell battery and in fact the battery is not a Gel Cell.

AGM: The Absorbed Glass Matt construction allows the electrolyte to be suspended in close proximity withthe plates active material. In theory, this enhances both the discharge and recharge efficiency. Common manufacturerapplications include high performance engine starting, power sports, deep cycle, solar and storage battery. The larger AGMbatteries we sell are typically good deep cycle batteries and they deliver their best life performance if recharged before allowedto drop below the 50% discharge rate. The Scorpion motorcycle batteries we carry are a nice upgrade from your stock floodedbattery, and the Odyssey branded batteries are fantastic for holding their static charge over long periods of non use. When DeepCycle AGM batteries are discharged to a rate of no less than 60% the cycle life will be 300 plus cycles.

GEL: The Gel Cell is similar to the AGM style because the electrolyte is suspended, but different because technically the AGMbattery is still considered to be a wet cell. The electrolyte in a Gel Cell has a silica additive that causes it to set up or stiffen. Therecharge voltage on this type of cell is lower than the other styles of lead acid battery. This is probably the most sensitive cell interms of adverse reactions to over-voltage charging. Gel Batteries are best used in VERY DEEP cycle application and may lasta bit longer in hot weather applications. If the incorrect battery charger is used on a Gel Cell battery poor performance andpremature failure is certain.

4. CCA, CA, AH and RC. What are these all about? These are the standards that most battery companies use to rate the outputand capacity of a battery.

Cold cranking amps (CCA) is a measurement of the number of amps a battery can deliver at 0 ° F for 30 seconds and not dropbelow 7.2 volts. So a high CCA battery rating is especially important in starting battery applications, and in cold weather.Thismeasurement is not particularly important in Deep cycle batteries, though it is the most commonly 'known' batterymeasurement.

CA is cranking amps measured at 32 degrees F. This rating is also called marine cranking amps (MCA). Hot cranking amps(HCA) is seldom used any longer but is measured at 80 ° F.

Reserve Capacity (RC) is a very important rating. This is the number of minutes a fully charged battery at 80 ° F will discharge25 amps until the battery drops below 10.5 volts.An amp hour (AH) is a rating usually found on deep cycle batteries. The standard rating is an Amp rating taken for 20 Hours.What this means, say for a 100 AH rated battery is this: Draw from the battery for 20 hours and it will provide a total of 100amp-hours. That translates to about 5 amps an hour. 5 x 20 = 100. However, it's very important to know that the total time ofdischarge and load applied is not a linear relationship. As your load increases, your realized capacity decreases. This means ifyou discharged that same 100 AH battery by a 100 amp load, it will not give you one hour of runtime. On the contrary, theperceived capacity of the battery will be that of 64 Amp Hours.

5.Battery Maintenance is an important issue. The battery should be cleaned using a baking soda and water solution; a couple oftable spoons to a pint of water. Cable connections need to be cleaned and tightened as battery problems are often caused bydirty and loose connections. A serviceable battery needs to have the fluid level checked. Use only mineral free water, Distilledis best as all impurities have been removed, and there is nothing left that could contaminate your cells. Don't overfill batterycells especially in warmer weather because the natural fluid expansion in hot weather can push excess electrolytes from thebattery. To prevent corrosion of cables on top post batteries use a small bead of silicone sealer at the base of the post and placea felt battery washer over it. Coat the washer with high temperature grease or petroleum jelly (Vaseline), then place cable onthe post and tighten. Coat the exposed cable end with the grease. Most folks don't know that just the gases from the batterycondensing on metal parts cause most corrosion.

6. Battery Testing can be done in more than one way. The most accurate method is measurement of specific gravityand battery voltage. To measure specific gravity buy a temperature compensating hydrometer, to measure voltage use a digitalD.C. Voltmeter. A quality load tester may be a good purchase if you need to test sealed batteries.

For any of these methods, you must first fully charge the battery and then remove the surface charge. If the battery has beensitting at least several hours (I prefer at least 12 hours) you may begin testing. To remove surface charge the battery must bedischarged for several minutes. Using a headlight (high beam) will do the trick. After turning off the light you are ready to testthe battery.

State of Charge Specific GravityVoltage 12V 6V100% 1.265 12.7 6.375% 1.225 12.4 6.250% 1.190 12.2 6.125% 1.155 12.0 6.0Discharged 1.120 11.9 6.0

Load testing is yet another way of testing a battery. Load test removes amps from a battery much like starting an engine would.A load tester can be purchased at most auto parts stores. Some battery companies label their battery with the amp load fortesting. This number is usually 1/2 of the CCA rating. For instance, a 500CCA battery would load test at 250 amps for 15seconds. A load test can only be performed if the battery is near or at full charge.

The results of your testing should be as follows:

Hydrometer readings should not vary more than .05 differences between cells.

Digital Voltmeters should read as the voltage is shown in this document. The sealed AGM and Gel-Cell battery voltage (fullcharged) will be slightly higher in the 12.8 to 12.9 ranges. If you have voltage readings in the 10.5 volts range on a chargedbattery, that typically indicates a shorted cell.

If you have a maintenance free wet cell, the only ways to test are voltmeter and load test. Any of the maintenance free typebatteries that have a built in hydrometer(black/green window) will tell you the condition of 1 cell of 6. You may get a goodreading from 1 cell but have a problem with other cells in the battery.

When in doubt about battery testing, call the battery manufacturer. Many batteries sold today have a toll free number to call forhelp.

7. Selecting a Battery - When buying a new battery I suggest you purchase a battery with the greatest reserve capacity or amphour rating possible. Of course the physical size, cable hook up, and terminal type must be a consideration. You may want toconsider a Gel Cell or an Absorbed Glass Mat (AGM) rather than a Wet Cell if the application is in a harsher environment orthe battery is not going to receive regular maintenance and charging.

Be sure to purchase the correct type of battery for the job it must do. Remember that engine starting batteries and deep cyclebatteries are different. Freshness of a new battery is very important. The longer a battery sits and is not re-charged the moredamaging sulfation build up there may be on the plates. Most batteries have a date of manufacture code on them. The month isindicated by a letter 'A' being January and a number '4' being 2004. C4 would tell us the battery was manufactured in March2004. Remember the fresher the better. The letter "i" is not used because it can be confused with #1.

Battery warranties are figured in the favor of battery manufactures. Let's say you buy a 60-month warranty battery and itlives 41 months. The warranty is pro-rated so when taking the months used against the full retail price of the battery you end uppaying about the same money as if you purchased the battery at the sale price. This makes the manufacturer happy. Whatmakes me happy is to exceed the warranty. Let me assure you it can be done.

8. Battery life and performance - Average battery life has become shorter as energy requirements have increased. Twophrases I hear most often are "my battery won't take a charge, and my battery won't hold a charge". Only 30% of batteriessold today reach the 48-month mark. In fact 80% of all battery failure is related to sulfation build-up. This build up occurs whenthe sulfur molecules in the electrolyte (battery acid) become so deeply discharged that they begin to coat the battery's leadplates. Before long the plates become so coated that the battery dies. The causes of sulfation are numerous. Let me list some foryou.

Batteries sit too long between charges. As little as 24 hours in hot weather and several days in cooler weather.Battery is stored without some type of energy input."Deep cycling" an engine starting battery. Remember these batteries can't stand deep discharge.Undercharging of a battery to only 90% of capacity will allow sulfation of the battery using the 10% of battery chemistry notreactivated by the incompleted charging cycle.Heat of 100 plus F., increases internal discharge. As temperatures increase so does internal discharge. A new fully chargedbattery left sitting 24 hours a day at 110 degrees F for 30 days would most likely not start an engine.Low electrolyte level - battery plates exposed to air will immediately sulfate.Incorrect charging levels and settings. Most cheap battery chargers can do more harm than good. See the section on batterycharging.Cold weather is also hard on the battery. The chemistry does not make the same amount of energy as a warm battery. A deeplydischarged battery can freeze solid in sub zero weather.Parasitic drain is a load put on a battery with the key off. More info on parasitic drain will follow in this document.

There are ways to greatly increase battery life and performance. All the products we sell are targeted to improveperformance and battery life.

An example: Let's say you have "toys"; an ATV, classic car, antique car, boat, Harley, etc. You most likelydon't use these toys 365 days a year as you do your car. Many of these toys are seasonal so they are stored. What happens tothe batteries? Most batteries that supply energy to power our toys only last 2 seasons. You must keep these batteries fromsulfating or buy new ones. We sell products to prevent and reverse sulfation. The PulseTech products are patented electronicdevices that reverse and prevent sulfation. Also Battery Equaliser, a chemical battery additive, has proven itself very effectivein improving battery life and performance. Other devices such as Solar Trickle Chargers are a great option for batterymaintenance.

Parasitic drain is a load put on a battery with the key off. Most vehicles have clocks, engine management computers, alarmsystems, etc. In the case of a boat you may have an automatic bilge pump, radio, GPS, etc. These devices may all be operatingwithout the engine running. You may have parasitic loads caused by a short in the electrical system. If you are always havingdead battery problems most likely the parasitic drain is excessive. The constant low or dead battery caused by excessiveparasitic energy drain will dramatically shorten battery life. If this is a problem you are having, check out the Priority Start andMarine Priority Start to prevent dead batteries before they happen. This special computer switch will turn off your enginestart battery before all the starting energy is drained. This technology will prevent you from deep cycling your starting battery.

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9. Battery Charging - Remember you must put back the energy you use immediately. If you don't the batterysulfates and that affects performance and longevity. The alternator is a battery charger. It works well if the battery is not deeplydischarged. The alternator tends to overcharge batteries that are very low and the overcharge can damage batteries. In fact anengine starting battery on average has only about 10 deep cycles available when recharged by an alternator. Batteries like to becharged in a certain way, especially when they have been deeply discharged. This type of charging is called 3 step regulatedcharging. Please note that only special SMART BATTERY CHARGERS using computer technology can perform 3 stepcharging techniques. You don't find these types of chargers in parts stores and Wal-Marts. The first step is bulk charging whereup to 80% of the battery energy capacity is replaced by the charger at the maximum voltage and current amp rating of thecharger. When the battery voltage reaches 14.4 volts this begins the absorption charge step. This is where the voltage is held ata constant 14.4 volts and the current (amps) declines until the battery is 98% charged. Next comes the Float Step. This is aregulated voltage of not more than 13.4 volts and usually less than 1 amp of current. This in time will bring the battery to 100%charged or close to it. The float charge will not boil or heat batteries but will maintain the batteries at 100% readiness andprevent cycling during long term inactivity. Some Gel Cell and AGM batteries may require special settings or chargers.

10. Battery Do'sThink Safety First.Do read entire tutorialDo regular inspection and maintenance especially in hot weather.Do recharge batteries immediately after discharge.Do buy the highest RC reserve capacity or AH amp hour battery that will fit your configuration.

11. Battery Don'tsDon't forget safety first.Don't add new electrolyte (acid).Don't use unregulated high output battery chargers to charge batteries.Don't place your equipment and toys into storage without some type of device to keep the battery charged.Don't disconnect battery cables while the engine is running (your battery acts as a filter).Don't put off recharging batteries.Don't add tap water as it may contain minerals that will contaminate the electrolyte.Don't discharge a battery any deeper than you possibly have to.Don't let a battery get hot to the touch and boil violently when charging.Don't mix size and types of batteries.

There are many points and details I have not written about because I wanted to keep this as short and simple as possible.Further information can be found at the links below. If you are aware of sites with good battery maintenance information pleaselet me know.

Additional Battery Tutorial jgdarden.com

Written on February 11, 2015 a 6:41 pmTagged with batteries, AGM, flooded, Wet, gel,cell, tutorial, charging, sulfation305 Responses, 4.7 Rating

Subscribe to comments with RSS.What is the connection to the battery tocharge a 24volt systemJimmyJanuary 22, 2012 a 8:06 amReplyIf you have 2 batteries in series, the voltage increases. The most common form of 24 volt systems involves two 12 volt batteriesconnected together, a wire from the positive terminal of one battery to the negative on the other. For more information aboutconstructing battery banks, read this helpful article.http://www.batterystuff.com/kb/articles/battery-articles/battery-bank-tutorial.htmlIf you have a 24 volt charger, you must treat your two 12 volt batteries as if they were a single battery. The open terminals onboth ends would be the required positive and negative access points.JamesJanuary 23, 2012 a 8:50 amReply

This is just what I need to give me confidence in dealing with a battery issue. Much appreciated.DesmondJanuary 18, 2012 a 2:04 pmReplyJust to let you know that your battery basics piece was well written and useful. I appreciate your hard work and your passionfor your subject.Keith ClemensJanuary 23, 2012 a 7:38 amReplyLove it!! Once I read, K.I.S.S. I knew I would understand you! Thanks!WendyOctober 27, 2013 a 10:35 amReplyOver the last 40 years I have puchased endless numbers of leisure batteries for my caravans none have ever lasted more than 12mounths althouth I have charged them regularly.My latest one has just failed after 6 mounths and the manufacturers stamp 15indicates January 2005 surerly this must be one of the reasons they do not last the coarse.I have found out more about batteriessince reading Battery Stuff.Com although I am a retired motor engineer,Well Done.John HackneyJanuary 26, 2012 a 11:03 amReplyhi this is a common problem, many battery manufacturers make batteries that they claim are leisure batteries. the advice i willgive is that you should buy a battery with the largest amps as possible that will fit in the space that you have, in my opinion youshould buy an AGM battery as this will discharge and recover better after use, they are more expensive but should last muchlonger. thanks eric roberts www.batteriesontheweb.co.ukEric RobertsMarch 7, 2012 a 11:41 pmReplyAGM batteries do not last much longer than lead acid batteries, if they last an longer at all.JamieJune 14, 2012 a 6:01 pmReplyAGM technology is essentially the same as a lead acid battery. The only difference is the electrolyte is not free to spill, butabsorbed. This eliminates the need to maintain fluid levels, thus preventing a lot of premature failure caused by reflectance. Butmaintenance free does not mean the freedom from having to charge regularly. All lead acid batteries self discharge, and the bestway to see longest life is to keep fully charged as often as possible. Maybe you‘ve had some bad experiences with AGMbatteries. That‘s unfortunate.TechJune 15, 2012 a 8:43 amReplyAgreed, if properly maintained, a wet battery will last just about as long as an AGM battery. BUT, very few people actually dothe proper maintenance. Because AGM batteries are valve-regulated, have a slower self-discharge rate, recharg faster, etc, etc,they are more resilient than wet batteries and therefore, in real world use DO last much longer than wet batteries.SergioAugust 27, 2012 a 12:32 pmReplyIs it possible to have 12 volts from a battery and low or weak cca ? Also tell me if im thinking wrong , but I have theory , that abattery is allot like your arm , you arm has the 12 volts and the muscles in your arm potentially are your amps , you can withstand holding weight for a certain amount of time until you become weak and need to relax for a few moments before you can“crank” again , would you say that would be a good example if i were to try and explain how a battery functions to people whodon‘t speak english ?LarryJanuary 27, 2012 a 7:15 amReplyThat is a good example, yes. Some arms have less muscle mass and others have more. But all the same number of muscles inthe arm. 12 volt batteries all have 6 cells. Each cell is 2 volts. 2 × 6 = 12. But the cells have plates inside of them. The moreplates, the more current can run through, thus more CCA. Large and small batteries all have 6 cells, but the size and number ofplates can vary greatly. I hope this helps.JamesJanuary 27, 2012 a 9:23 amReplyif i could rate your article out of ten, i would give it ten.very informative alas i did not solve my problemwhat is the method of getting a rechargable battery to hold charge,

will short overcharging periods do the trick?JohnJanuary 30, 2012 a 9:31 pmReplyIf you‘re referring to a rechargeable lead acid battery, then there could be many reasons why a battery does not “hold acharge”. There could be a parasitic drain. There could be a short or open cell. There could be an internal defect such as a weakweld. Or the battery could simply be deeply discharged, and if you‘re using a smart charger, find that the charger simply will notcharge the dead battery. This is primarily due to the low voltage safety disconnect found in most microprocessor controlledchargers.JamesJanuary 31, 2012 a 7:44 amReplyVery important article on rechargeable batteries.We are planning to install Lead Gel batteries in our AS/RS equipments. Shall we go for Lead Gel or AGM type of batteries ?Why ? Give us advantages in terms of cost & safety while selecting the type of battery.Pls help us to decide.thanksJAYANTIFebruary 2, 2012 a 3:31 amReplyHello,Gel and AGM batteries are both nice because of the maintenance free nature and sealed case. The Gels are able to deepdischarge better (well, with less negative effects than the AGM). However, the Gel battery requires a compatiblecharger/regulator. Normal wet cels and AGM batteries effectively charge at 14.6 volts or higher. But the Gel battery should beno more than 14.2 volts. It really does make a difference. They are more fragile and can be damaged easier when charging.For more information, please read GEL Vs. AGM.http://www.batterystuff.com/kb/battery-articles/gel-vs-agm.htmlJames VilleFebruary 2, 2012 a 8:31 amReplyHi, I have an older 4 ×4 truck with no electronics. However, I have an inverter to power (mainly laptops, gadgets), two externallights but no winch. My current alternator is rated at 75amps and my current battery at 80ams / CCA 780 / CR 120. I want toinstall a split batteyr system (solenoid+monitor) along with another batter (same power or slightly higher). Do I need to upgrademy alternator.. say to a 100 amps? Can a 75amp alternator comfortably charge both batteries..given than I‘m using a “smart”split battery charging system? or am I asking for trouble….ie: a dead alternator? ThanksBertFebruary 4, 2012 a 5:19 pmReplyYou would be best off going with the larger alternator. 75 amps may be enough, but upgrading to the 100 amp system wouldmake sense.JeremyFebruary 6, 2012 a 2:40 pmReplyTwo weeks ago I purchased a new car Buick Enclave that had been on the lot for an extended period of time. Everythingseemed to be fine until I took a long trip (10hrs). The next morning I used the remote start to warm up the car then turned it offand continued to load the car using the remote hatch lift several times. About ten minutes later I got in the car and didn‘t haveenough battery to start it. I was able to get a boost to start the engine and return home (10hrs). I took the car to the dealer thenext morning to have it checked out and was told the battery was good as it checked out at 12.3 volts. Doesn‘t that show adischarged battery? Should the charging system maintain the battery at 12.6 to 12.8 volts? The next step is to have the electricaloutput checked. I would appreciate your input as to what I should have them check next. ThanksBob GFebruary 9, 2012 a 2:20 pmReplyHello Bob,You are correct. The battery should be reading more than 12.3 volts. If the battery cannot reach over 12.6 volts, then there islikely a sulfation problem. the more sulfation on the plates, the less surface area. in turn, that results to less power andpre-mature failure.James VilleFebruary 9, 2012 a 2:50 pmReplyOptimum battery voltage is 12.6 volts at 70 farenheit. Specific gravity and voltage will drop with temperature. 12.3 is a goodvoltage. What the battery loads down to is more important.Lester Cheeks

November 10, 2014 a 10:07 pmReplyhi I am extremely interested in the subject and would like to thank you for clearing up a few things that i had previously notknown.Denise KeilholtzFebruary 14, 2012 a 4:31 pmReplyhey, i am trying to charge 2 deep cycles in parallel with a 6 amp charger (12v) is this any diffrent than charging a single?Kris FFebruary 16, 2012 a 1:10 amReplyWhen you charge 2 deep cycle batteries in parallel, you’ve essentially doubled your capacity. The charger will recognize yourbattery bank as a single battery. If your 6 amp charger took 4 hours to charge one battery, it will now take 8 to charge both. Theresistance has increased with the increase in capacity, so it will take longer to charge. As for the connections, you can hookyour charger to the positive and negative terminal from one battery or both. For a 2 battery system, it doesn’t make adifference.JamesFebruary 16, 2012 a 8:32 amReply“The resistance has increased with the increase in capacity,” Not so, resistances in parallel decrease. It takes longer to chargebecause you are charging two batteries at the same time instead of one.PaulApril 15, 2012 a 8:49 amReplyResistance is based on the internal battery chemistry. It‘s not constant, but it relates to the strength of the charge rate versus thestate of charge in the batteries. Two batteries in parallel will indeed lower the resistance. The charge time may not be quicker,but it will be more efficient.TechApril 16, 2012 a 11:03 amReplyI have a few questions about sulfation removal.1. How can a person determine how much sulfation has occurred inside a battery?2. Which de-sulfation device do you most highly recommend to remove sulfation from battery plates?3. How much time is required to fully de-desulfate a battery? If the de-sulfation device isn‘t capable of fully de-sulfating abattery, can you let me know how much de-sulfation such a device can provide.Thx, ZZFebruary 17, 2012 a 4:37 amReply1)There is no exact way to determine the amount of sulfation, but a hydrometer is helpful. By telling the specific gravity, youcan determine the strength of the electrolyte. Typically, the more sulfation on the plates, the weaker the strength of electrolyte.If you have sealed batteries, a hydrometer will not work.2)If you have a flooded battery, I recommend using Battery Equalizer in conjunction with a pulsing charging, such as BatteryMINDer or PulseTech. Exact model will depend on the capacity of your battery.3)You’ll see the most dramatic results after about 2 weeks of continuous pulsing. The harder, crystallized sulfate which took along time to build up may take an additional 2 months before reaching a another restore point. On average, a de-sulfated batterymay be restored up to 80% of its original factory capacity.JamesFebruary 17, 2012 a 9:58 amReplyI am purchasing a 125 watt solar panel and want to purchase two 12 volt RV batteries.I dry camp alot and want to be able tomaximize my reserve capacity using the solar charging to replenish the drain on the batteries. My question is what size batteryre the 20 hr amp rating would you recommend using two twelves and AGM or Gel? I do not winter camp so majority of use isApril to Oct. Apprecite your expertise.Thanks TPToddFebruary 22, 2012 a 6:21 pmReplyIf want to size the batteries, you will need to know your load amount. If you have this, please use our Sizing a 12 Volt Battery toa Load Calculator found here:http://www.batterystuff.com/kb/tools/calculator-sizing-a-battery-to-a-load.htmlIf your solar controller has a gel profile, then having a gel battery is not a problem. They can deep discharge better than AGM,but are more expensive.

James VilleFebruary 23, 2012 a 12:01 pmReplyGreat informative article. Just wondered if you or any of your readers have experienced or heard of problems with BMWautomobile batteries? This is a well know and documented issue by many BMW owners and dealers? Due to the inordinatenumber of battery life failures BMW no longer honors their new car battery warranty. By downloading historical informationfrom the automobile‘s computer the dealer will look for any excuse for blaming the problem on the car owner, e.g., leaving thedoor open, leaving the key in the car, or not driving the car for several weeks. It seems to me that BMW has a problem withparasitic drain on their cars from about the time that the 2008 models came out. The car computer remains active when theengine is off, still controlling functions that I cannot explain. BMW has not compensated for this parasitic drain by installing aheaver duty (more Amp Hours) battery. I can‘t believe their engineers are this ignorant. An easy saluting would be to paralleltwo batteries but this would increase the cost of the vehicle by several hundred dollars. That is probably why BMW has takenno action to correct the problem. It is possible that other automobile manufacturers have similar problems. My opinion is that ifnew batteries cannot be designed to compensate for the heavy parasitic drain then the manufactures need to install two parallelbatteries or come up with procedures to connect an external battery trickle changer when the car is parked overnight.John CFebruary 23, 2012 a 5:43 pmReplyThat‘s a good suggestion. A Trickle Charger is the best step to take in extending the life of the battery. It‘s less expensive than anew battery, that‘s for sure.James VilleFebruary 24, 2012 a 7:49 amReplyBMW cars and some Mercedes Benz have had issues with on board computers,after disconnecting the engine heater wiring andcomputer reset the problem was solved. Disconnect the battery,disconnect the heater wiring at engine, reconnect battery, turnon ignition 20 seconds, turn off. Then start engine, if no startyou have to reconnect the wiring on some models warning faultlight will stay on for some time. Our workshop solved most problems.Over sophisticated temp (seats, engine) and security sensors and free radical computer connections can create the power useproblem. If you can find a reset button/or code it helps.Keith VandereeJune 25, 2014 a 1:29 amReplyGood advice, thanks!TechJune 25, 2014 a 9:00 amReplyI‘m shopping for a couple of off-grid batteries , I‘m curious when purchasing a new battery, what is the typical warranty length,in case you bought a dud that was sitting in the heat in storage for 12 months. Thanks, great info BTWYancyFebruary 24, 2012 a 11:33 amReplyAll of our batteries have their warranties listed on the product pages. Typical warranties start at 1 year for most of ourpowersports batteries. Shorai and Odyssey high performance batteries have 2 year warranties.James VilleFebruary 24, 2012 a 11:56 amReplyI have an interesting battery question for AGM battery charging. I recently purchased a 12 volt 7 amp battery for my roboduck,I used my older 1/2 amp charger adn about two hours later, I noticed the battery had a puddle of clear water around it‘s base. Itwas acid! How on earth could a glass matt battery generate that much fluid (about 1/4 cup). I did nto even think there was thatmuch fluid in the battery! What is going on?Tom ZFebruary 29, 2012 a 9:55 amReplyAGM batteries are sealed. If there is a large pool of electrolyte, there must be an opening in the case. If the liquid is not comingfrom the ventilation holes on the top, there must be physical damage elsewhere, possible near the base.The electrolyte in the battery is absorbed, but it can be forced out if there is enough pressure in the case or if it hasn‘t had timeto fully absorb (for instance, it if was a freshly activated battery).James VilleFebruary 29, 2012 a 10:04 amReplyI have a Sportster scooter which is seven years old and has two 12V deep cell GEL type batteries. It has been used very little.These batteries won‘t take a charge. When I disconnect them to read the voltage I get 11 volts on one and 13 volts on the other.Gel types (80AH) for this unit are super expensive.

(1)Could I try to replace the 11 volt battery only, presuming its a dead cell?(2)Would you recommend that I replace these batteries with two AGM batteries with a comparable AH rating? Can I use thesame charger on these batteries?(3) Any other way out of this dilemma, such as using a maintenance-free lead acid battery with a comparable AH?Thanks very much, JohnThanks very muchJohn PaciorekMarch 2, 2012 a 6:07 amReply1) If you‘re reading 11 volts, there is no short or dead cell. It‘s much less expensive purchasing a de-sulfator unit to restore thebattery than to buy a new one. If the batteries are still holding a charge, they can be restored.2) If you do decide to upgrade to AGM, your Gel charger will work. Commonly, AGM batteries charge best at a higher voltage,but those chargers would damage the Gel.3) When creating a battery bank, it‘s recommended to use batteries of the same voltage, AH rating, and type. 80AH AGMbatteries will work for your system just fine, but good battery maintenance is still recommended, regardless of the batterychemistry type.James VilleMarch 2, 2012 a 9:29 amReplyHow is that one would determine that an 11 volt reading is not associated with a shorted cell?RangerJune 19, 2012 a 11:20 amReply11 volts cannot be a short cell, as each cell can read 2 volts or more. Therefore, a battery with a short cell typically reads 10.5volts or less. But an open cell is different. This has to do with a weld piece disconnecting under the load, and voltage usuallydrops significantly or sometimes flatlines when this happens.TechJune 20, 2012 a 12:41 pmReplyHi, I have four 6 volt house batteries for my RV. We do some warm weather dry camping. How low should I let the voltage dropbefore recharging with the generator? Thanks, RickRick EcholsMarch 2, 2012 a 9:06 amReplyLead Acid Batteries, doesn‘t matter the voltage, should never be left to drop in voltage. That is only common practice withNiCD batteries. Discharging your batteries severely before recharging them will cause sulfation and early battery failure. Thehealthiest thing to do is keep them fully charged as often as possible.James VilleMarch 2, 2012 a 9:11 amReplySo how can I expect to be able to use my house batteries for dry camping without losing any voltage? I would think that Ishould be able to use my lights inside and radio without runnung my generator. I don‘t want to have to run my generator all thetime.Rick EcholsMarch 2, 2012 a 9:25 amReplyLosing voltage is normal. Good battery maintenance is as follows: Re-charge battery at the soonest possible after using thebattery. When drawing from the battery, avoid discharging below 50% capacity. This is the danger of having a battery sit instorage for months at a time. You will see early battery failure. Charging regularly or keeping a trickle charger is the bestsolution.Surely batteries are meant to be used. But the myth of “battery memory” does not apply to lead acid batteries. It is not healthy,and unnecessary, to discharge all the way and recharge again.James VilleMarch 2, 2012 a 9:35 amReplyThank you James, for all the great information!Ive got an electric scooter (xtreme xb-600) and need to replace the 12v22ah SLA. Ive looked around and was told that theEVX12200 or EVH12240 Deep Cycle Battery would be the way to go.Your opinion would be muched valued and appreciated!EagleyeMarch 5, 2012 a 5:33 pmReplyYes, those batteries will work as they are the same dimensions as any 12 volt 22 AH SLA Battery. The difference between the

EVX12200 and the EVH12240 is AH rating. The higher the AH, the more runtime you‘ll have.James VilleMarch 6, 2012 a 8:46 amReplyJames, this is a great site! Maybe you can help me: I have 3 8D AGM marine batteries on my boat with a xantrex chargingsystem. The boatyard said they would plug the boat in over the winter in the warehouse but did not. Nor did they shut thebreakers off. So, the batteries were depleted to zero over the last 5 months. How can I tell what damage was done? How can Icalculate the liability the boatyard has?Greg WhiteMarch 8, 2012 a 4:21 pmReplyWhile it‘s difficult to quantify the damage, I have some recommendations.First, you should take a voltage reading from the batteries. If indeed you‘re reading 0 volts (which is unlikely) then I would tryto charge them with a low voltage start charger ASAP. Most automatic chargers have a cut-off voltage of 6.5 volts before theywill start. This prevents you from bringing back severely discharged batteries. Interacter makes a charger that starts chargingwith a reading as low a 1-2 volts.Second, sulfation has most definitely occurred, so I would also advise putting a de-sulfator unit on the batteries as well, such asthe OBD12V. If these do not bring the battery back to working condition, then I would suggest the batteries have passed thepoint of no return.James VilleMarch 9, 2012 a 9:30 amReplyhi all i bought a AGM battery for my kawasaki vn 1500, great more ca,s no probs with it until i went overseas to work and madethe mistake of leaving the ignition switch turned to park!, THIS in turn left the rear lamp illuminated, returned back home 6weeks later ZILCH,visited my local bike guru in redcar he put slow charges, then fast charges into it over a period of two days,its gone from an initial reading of 0.3 v to a steady 12.9, hope this helps the guy with the boat.Knobby IonsMay 8, 2012 a 8:53 amReplyHey, that‘s great that your batteries came back! 12.9 is very good voltage. Thanks for sharing!TechMay 8, 2012 a 9:59 amReplyWonderful article. Just had a question though.How does one test SMF batteries on-site for e.g. Server UPS batteries. ? The test-gig should be portable though.PhyleusMarch 12, 2012 a 3:30 amReplyWhat do you need to test for? Voltage readings with a volt meter is always helpful. This gives you a good idea of the state ofcharge of the batteries. A Load tester is good for measuring CCA and durability under a load. Even our comprehensive digitalbattery conductance analyzer is portable. All of our testing units are located in the Battery Accessories category on our website.See for yourself. :)James VilleMarch 12, 2012 a 11:58 amReplyhello Jamie, I am currently working on a research about Solar- hybrid off-grid instalations,I have my battery amp hour for 20hrs discharge but i need the battery to store enuf cahrge for 3 days, so ut is trippled, do i stilluse the C20 rating or do i use the C72hrs rating for it? i am confused. and the needed Current is about 6000Amp-hourJummyMarch 13, 2012 a 2:49 amReplyIf you parallel your batteries, the capacity (AH) will increase. The rating will still be at 20 hrs, but the number will triple.If you have your batteries and draw amount, please use our battery calculators to help you figure out how long they will last, orif you need another battery based on your load.http://www.batterystuff.com/kb/tools/James VilleMarch 13, 2012 a 9:14 amReplyNext time simple is enough…..DeronMarch 12, 2012 a 10:16 amReplyVery good overview of lead-acid batteries. How do I submit a question? What type of sealed lead-acid battery would a

handicap scooter likely have: AGM or Gel? I need to know in order to select the right charging mode for a Schauer automaticcharger.Mel SchallotMarch 12, 2012 a 10:46 amReplyMobility Scooters use both AGM and Gel batteries. I cannot verify what you have. However, if you‘re unsure, I recommendusing the Gel setting. This is a lower voltage that is safe for gel, but the AGM will accept it also. It‘s the other way around thatis not recommended.James VilleMarch 13, 2012 a 11:56 amReplyFantastic information. Thanks so much for your service to those of us struggling to understand through all the hype. Myquestion is for a marine application. I have a bank of 4 Trojan lead acid batteries for my house bank and another lead acidstarter battery. My starter battery died and I‘d like to replace it with a maintanence-free option but have heard not to mixbattery types. I‘m not ready to replace the Trojans, so should I just buy another lead-acid starter to tide me over until myTrojans die? Thanks for any suggestions you can give.Toni RoddeyMarch 13, 2012 a 2:19 pmReplyIf your starter battery is not connected to the house bank, then it‘s fine to upgrade it to a sealed type. You can even use thesame charger if you go with an AGM. Within a battery bank it‘s recommended to use the same battery type. Because your boatdraws from the house bank and the starting batteries separately, then you‘re okay.James VilleMarch 13, 2012 a 3:28 pmReplyhave a 6 volt dry cell batt. in a old bike. is there a way of protecting the batt. from being over charged? thank you for yourtime..GaryMarch 17, 2012 a 6:33 amReplyThe best method to preventing battery from being overcharged is to use a micro-proccessor controlled “smart” automaticbattery charger. If the bike itself is over-charging, then there is a problem with the bike‘s charging system, the stator.James VilleMarch 19, 2012 a 11:06 amReplyThank you for the excellent article and taking the time to answer everyone‘s questions. I want to install a dual battery system ina small car that has an 80 amp alternator. The 2nd battery will be dedicated to one appliance that has a low current draw. Asmall deep cycle AGM like those used in mobility scooters will do the trick (about 35 Ah). I don‘t want to upgrade thealternator but I also don‘t want to overly stress the one I‘ve got by having it regularly recharge a battery that is often going tobe drained close to max (50 percent). Is there a way that I can limit the current to the second battery so that it charges at 10 to15 amps? That would be equivalent to driving with lights on and so I know it would not have a big negative effect on thealternator as long as I am not using the lights.Bill SmithMarch 18, 2012 a 12:40 amReplyIf you want to charge your vehicle‘s starting battery as well as a separate auxiliary battery, I recommend using the BatteryIsolator Switch (Bi303303). Having a 35 AH spare battery should not be too much for your 80 amp alternator. It‘s an automaticdevice, there is no “preset” amperage setting. The charge allocated to the batteries really depends on the status of each one.With the rise in resistance in one battery, charge will be directed to the other until they are both stable and full.James VilleMarch 20, 2012 a 11:46 amReplyHi,I only use my car on weekends. My question is: Can I use a Smart Charger whenever the car is stopped? This will notovercharge the battery?My car has an AGM battery.Thanks in advance for your help.CainMarch 18, 2012 a 11:55 amReplyIf you use an AC charger, parking the car and turning off the engine is fine. If you are refereing to a solar charger, it‘s alsodesigned to charge the battery, not only when the car is stopped, but the engine is off as well. Plugging a smart charger on thecar during the weekdays is very healthy for the battery. No overcharging if you make sure the charger is fully automatic. Our

chargers are. :)James VilleMarch 19, 2012 a 11:30 amReplyThe article above suggests you know what you‘re talking about. I don‘t know jack, but have read a little online and am trying touse a deep-cycle battery to power a projector for a public art project. Any chance you‘re available to help me trouble-shoot? Iborrowed a neighbor‘s charger and charged a brand new battery up for about 15 hours. I then hooked up a 1000watt inverterand plugged the projector in. It worked great, for about 25 minutes, but then just died with a Low Voltage error message. Doesthis mean the battery wasn‘t charged all the way or am I doing something else wrong? According to the projector specs, themax wattage it uses is 288. Would really appreciate any input you‘ve got. I‘m out of my league here.ShawnMarch 19, 2012 a 12:04 pmReplyBased on the information you provided, you‘re drawing around 23 amps from a 12 volt battery. That‘s a lot of juice since it‘s aconstant draw, not a quick burst. Without any information about the battey itself, or the charger, I cannot determine what theproblem was.If the battery did not have the capacity to handle the load, you may need something with more AH (Amp Hours). It might behelpful if you run your numbers through our calculators.http://www.batterystuff.com/kb/tools/Or give our tech guys a call at 541-474-4421James VilleMarch 19, 2012 a 12:58 pmReplyAwesome article – thanks. I have a question.I have a YP17-12 (12V17AH) Maintenance Free Lead Acid battery in my Bushranger Power Tank (for jump starting). It‘s wasshowing over 12 volts after about 10 hours at 1 amp. I tried to load test (it failed) and it‘s now just under 12 volts. It has aplastic strip which when I popped it off with a screwdriver there were little caps on each filling hole. Can I add distilled water toit even if it had gel. I up-ended it with caps off over a container and not a single drop of liquid came out making me think it isnot a wet acid type. Your thoughts would be greatly appreciated.Andrew D-HMarch 20, 2012 a 5:22 amReplyIf the battery is indeed maintenance free, it is not designed to be opened and water added. Low voltage is not a result of lowfluid levels, in this case. A fully charged battery should read 13.2-12.8 volts. If you read 12.0 or 12.2 volts, that‘s severelydischarged. If you load test at this poin, you‘ll only further discharge the battery. I recommend putting the battery on a chargerimmediately and load testing once it‘s fully charged.If the battery is draining rapidly in 10 hours at 1 amp, I recommend you use our online tools to calculate if that‘s a good sizebattery for that amount of draw, or if the draw time should be shortened for the sake of the battery.http://www.batterystuff.com/kb/tools/James VilleMarch 20, 2012 a 10:54 amReplyThank you for that info. Well meaning folks online were driving me nuts telling me that a deep cycle battery that is oftendischarged to 50 percent will greatly shorten the life of a small alternator. But I couldn‘t find any info like that at a reputableweb site and I‘m glad to hear it isn‘t really true. I had been looking at a VSR (voltage sensitive relay) for the part of the wiringyou mentioned. These (I guess they are all the same) charge the starting battery first and then switch the charging current to theauxiliary battery. Does the isolator you mentioned work that way? If not, which method do you think is best. I know thecompanies that make the VSR devices are always touting the fact that there is no voltage drop with their devices which I gatherthere is with a device that uses a solenoid.Bill SmithMarch 23, 2012 a 11:27 amReplyJames,I have a boat with 2 cyl diesel engine and currently 2 series 27 wet batteries set as two banks. I would like to add another 2batteries because the engine does not start easily when cold. The question is whether it is advisable to mix AGM‘s as one bankwith wet cells as the other. I would like to change to AGM‘s, but hate to lose the investment already made in the two wetbatteries. For starting, I do have a standard A/B or BOTH as a switching option for the banks.RichMarch 28, 2012 a 7:23 amReplyWhen constructing battery banks, it‘s highly recommened to use batteries of the same type (Flooded, AGM, Gel), voltage, AHrating, and even age. Although you can technically build your banks by adding AGM batteries, having these differences willcause an inbalance of discharge and recharging.

James VilleMarch 28, 2012 a 8:01 amReplyA very useful site, and highly informative – well done!I have two flooded lead acid for my domestic bank, and have added a small AGM for the engine start. The mains charger canbe configured for one type or the other – in my situation would it be better to set the charger to AGM type?bobBobbyMarch 31, 2012 a 6:46 amReplyFrom our experience, Flooded and AGM batteries can be charged at the same charge voltages. It should be safe either way.TechApril 2, 2012 a 8:16 amReplyExcellent information. Thanks.Just bought a DieHard Platinum Marine Group 31 for my boat. The reviews on this battery are excellent and I plan to use it forboth starting the boat and running the trolling motor. You mentioned needing a special charger for AGM batteries. I have aStanley BC4009 40 amp 3 stage charger. Is this charger OK to use with the AGM battery? Do I have to disconnect the batteryfrom the power cables to charge it? Thanks for your help!ChadApril 7, 2012 a 1:16 pmReplyAGM Batteries can be charged with most standard chargers. It‘s the Gel batteries that require a special charge profile. If youcharge your battery, you don‘t have to disconnect the power cables as long as the battery isn‘t being used while you charge it,unless your charger is also a power supply. If you draw on the battery while the charger is turned on, the charger will attempt tosupply the demand.TechApril 9, 2012 a 9:23 amReplyWell then, if a modern automobile with all it‘s current drawing electronics is to be charged using a smart charger, are yousuggesting that the cables be disconnected while charging the battery? What difference would it make if cables were left onduring the charging process? ThanxJohnAugust 17, 2012 a 2:03 pmReplyHaving the battery connected to the vehicle will cause a slight discharge as a result of the electronics. But normally it‘s notmuch. A charger will stil charge just fine but if the draw amount of the car is excessive, it can cause the charger to become lessefficient.TechAugust 17, 2012 a 2:20 pmReplyLots of good stuff here—-and well written so that weekend mechanics like me can understand it. I have a 36v Western GolfCar with 2 year old batteries. The charger came with the car and I recharge after every use. None-the-less, two cells have failedon each of two of the batteries. Your article recommended that I should not ‘mix and match’ batteries, but I would like toreplace the two failing batteries with new ones to get another year or so out of the remaining 4 old batteries. They cost about$125 each so my fix would invest $250 now to stave off a $750 pay out for another year. Bottom line: If I follow your advice, Ireplace all batteries at the same time and chuck 4 fairly good batteries (with no resale value). Is there a middle ground—-suchas using some of your products to bring the two batteries back to service??TomApril 9, 2012 a 4:38 amReplyThe choice is yours. The reason we recommend using batteries of the same age is because you will see overall betterperformance and lifespan of the whole bank if you do this. But if you feel it‘s not practical, you buying 2 new batteries willmake your bank work and it might be just fine for you. It‘s not optimal, but it makes more sense. If your old batteries have shotcells, there is no product that can reverse that.TechApril 9, 2012 a 9:35 amReplyI have a 12 volt portable battery (Sears Diehard Portable Power 1150) that I use for car camping trips and the occasionaljumpstart. I wasn‘t keeping it charged all the time and the battery finally wouldn‘t take a charge anymore. So I was convincedto replaced it with a deep cycle agm battery. After reading your article, it seems apparent that I should not have used a deepcycle because it‘s not appropriate for jumpstarts. However, I have also found that after the first time I used the battery for aweekend of camping, I had drained it down to 10% and now it will not charge. Is it possible that the unit is not compatible with

deep cycle batteries, or is it more likely that I overdrained it and the unit isn‘t registering a battery to charge? I was told that Ican connect this unit to my car battery (or any other charged 12 volt battery) and that should trick the unit into charging thebattery. What do you think?BudgeApril 10, 2012 a 12:27 pmReplyDeep Cycle batteries have CCA ratings as well. However, for the same physical size battery, if you compare it to a startingbattery, the CCA will be much less. But a deep cycle battery is fairly common in jumpstarts because they are also used as 12volt power sources and some even have built in inverters for AC power. The batteries in the units are large enough where theCCA can jump start a car. In doing so, 25% of the battery‘s capacity can be drained just like that. If batteries read severely lowvoltage, most automatic chargers have trouble charging. Connecting another battery in parallel with the drained battery is agood method of bypassing the “low voltage disconnect” filter of the charger.TechApril 10, 2012 a 2:06 pmReplyVirgin lead vs. recycled lead?Is there a life span difference between batteries constructed with virgin lead compared to one made with recycled batteries,assuming that all other conditions are equal? If there is a difference, is it a noticeable one?FrankApril 16, 2012 a 9:30 amReplyYes. Batteries made from virgin-lead perform better and will last longer. High performance batteries, such as Odyssey, also have2 year warranties.TechApril 16, 2012 a 11:19 amReplyHello,I asked a question a few weeks ago and have been looking for a reply. My question is about running LED lights on a 12v vs a24 volt system. I have 17 lights that are 27 watts each and want to get the maximum runtime. I have seen your calculators butdo not have all the imput parameters. The batteries I am thinking about are deep cycle with 210 reserve capacity. Thanks.BillApril 16, 2012 a 1:15 pmReplyMy question is this: what voltage are those lights rated for? If it doesn‘t say on the lights, you should find out by calling themaker. It‘s important to keep the voltage the same. Running a 12 volt rated LED light bulb will blow up if you use 24 volts (2batteries in series). Maximum runtime is ensured not my increasing the volatge amount, but the capacity (Amp Hours).TechApril 16, 2012 a 2:34 pmReplyI have a question. I purchased a Minn Kota Endura 50 trolling motor 2nd hand. It‘s for an aluminum fishing boat I have accessto once a year for a week. I‘m a casual fisherman who takes the boat out maybe for an hour a day. I bought a deep cycle AGM12 Volt 12 amp hour with a charger for agm and gel batteries. I had trouble finding what kind of draw the trolling motor placeson the battery at the Minn Kota site. Did I buy an undersized battery for my causal usage?DaveApril 20, 2012 a 3:29 pmReplySpeaking from experience with other customers with trolling motors, I can‘t imagine the motor pulling anything less than 15amps/hour from the battery. A 12 AH battery would not be able to supply more than 1/2 hour of power to the motor, if eventhat much. A larger capacity deep cycle battery would be highly recommened.TechApril 20, 2012 a 4:10 pmReplyI was afraid of that. Any suggestions as to what would fill my needs but would not be overbuying for what I do? I see some ofthe deep cycles run $400 or more. I don\‘t think I need that much power. Thanks for your reply. Obviously I\‘m new to makingthese calculations and a little leery of just walking into a store and having them sell me something.DaveApril 21, 2012 a 4:42 amReplyIf the motor drew at a rate of 15 amps an hour, I recommend using a group size 24 marine battery. This 12 volt, ~75 Amp Hourbattery should give you 2 hours of uninterrupted runtime, and only discharge the battery to the safe 50% capacity remaining.We sell these batteries for $200-250.TechApril 23, 2012 a 8:46 am

Replyi might have missed this in the article but, why is it not recommended to mix battery sizes, and not to mix battery types?cheersTrevApril 23, 2012 a 9:51 pmReplyBatteries of different types and sizes will charge and discharge unevenly. When batteries are configured in parallel or series (orboth) they behave as a single unit. If there is an imbalance it could mean a shortening of overall battery life, as well as potentialharm in recharging.TechApril 24, 2012 a 11:49 amReplyGreat info, my battery died today, so, the AAA guy said that my old battery was below 12.5 volts and that it wouldn‘t have orhold the amps?? what does this meanJack GilbertMay 5, 2012 a 8:09 pmReply12.5 volts is partially discharged, 70% capacity remaining. When a battery is put under a load and there are no “amps” goingthrough, it‘s usually a result of an open cell. The intense heat of a load can cause a separation in a cell connector, and this willcause current to decline or cease entirely. But when the load if taken off, the metal cools enough to touch and give a falsevoltage reading. It‘s very misleading and a result of poor construction at the factory level.TechMay 7, 2012 a 12:36 pmReplyOff the beaten track but several years ago my Dad bought me a 16V Craftsman drill. I used it a couple times and put it in thegarage. Recently I was cleaning up and found that drill but the battery was dead and refused to take a charge no matter what. Anew battery (when they can be found) is $55 plus. Do you know of any way to get this battery working again? Thanks.JimMay 8, 2012 a 11:48 amReplyWe sell a variety of power tool replacement batteries. You can view our selection at http://www.batterystuff.com/batteries/power-tool-batteries/Rebuilding a power tool battery pack will run around $30-35 and up. We will be offering battery rebuilding in the near future.TechMay 8, 2012 a 12:02 pmReplyMy husband just added acid instead of distilled water to my motorcycle battery after it had been sitting all winter. Is it ruined?S.May 9, 2012 a 4:09 pmReplyPossibly. The sulfuric acid never leaves the battery, it‘s only the water that evaporates and needs replenishment. If more acidwas put in, the pH levels are probably out of balance. The battery may still work, you should test it before going on the roadwith it.TechMay 9, 2012 a 4:17 pmReplyI have been charging my dead battery for 4 months using pulsetech smart charger. This dead battery has been leaving there for1 year.I got back my voltage of 13.7v and the smart charger is pulsing without mass charging for 1 week.However the battery still unable to start my car. The battery can supply headlight, horn and etc.Should i give up this battery or any other way to try it out?I notice 1 of the electrolyte\‘s in a cell is not drying up even after a long charge. the other cells always keep drying up andrequire to top up with battery water. Is the cell dead and cannot be revive anymore?thanks.YloonMay 14, 2012 a 10:35 pmReplyPlease refer to our article about Battery Troubleshooting. As far as battery water goes, as long as it‘s distilled water, that‘s fine.TechMay 16, 2012 a 10:53 amReplyWhen we use two batteries 12V each in a 24V system connected in parallel. There will be a possibility of unbalancing if boththe batteries have different manufacturing date or batch. The charger only knows to charge 24V even if one battery is at 14 and

other one is at 10. So it is thumb rule always connect same batch batteries in series and never replace one battery in a series.Replace the whole bank to avoid unbalancing. Unbalancing can damage one battery earlier than expected life.Kamran JabbarMay 16, 2012 a 4:23 amReplyWell said. Thank you for contributing.TechMay 16, 2012 a 2:44 pmReplyThe best ever. Your tutorials were written for dummies like myself.BobMay 17, 2012 a 6:46 pmReplyThank you for the feedback. :)TechMay 18, 2012 a 9:22 amReplyi have a 12 volt trolling motor and i just purchased an optima bluetop battery. These batteries are marketed as being dualpurpose (deep cycle and cranking). is it possible to connect two 12 volt batteries to power my trolling motor (i want to be on thewater as long as possible) and if so could i than use one of those 12 volt optima blue top dual purpose batteries as my crankingbattery for my engine? if any of this sounds dumb im sorry im very new to boating and im trying to figure all this out .JustinMay 20, 2012 a 3:37 pmReplyDeep Cycle batteries have a CCA rating as well. If you have a starting battery and a deep cycle battery of the same physicalsize, the starting battery will have far more CCA. It has to do the the thickness and number of the plates per cell. But if youhave a large marine battery, there‘s a good chance there will be enough CCA to turn over your engine. It‘s not unheard of.There‘s no harm in trying it out. It will either work or it won‘t.TechMay 22, 2012 a 10:27 amReplyI have a cpep that uses 2.2 amp I need to run it of a deep cell and a inverter for 8 hour for camping what what size inverter anddeep cell battery would I need?VinceMay 21, 2012 a 11:20 amReplyPlease use our online calculators to find the answer. They are located at http://www.batterystuff.com/kb/tools/ and they arevery easy to use.TechMay 22, 2012 a 9:46 amReplyis it possible to charge a 12 V battery with less than 12v?MatMay 21, 2012 a 1:00 pmReplyYes, but not fully. Proper charging requires inputting a higher voltage in order to bring up the battery voltage. For example, ifyour 12 volt battery is reading less than 6 volts, you can use a 6 volt charger to bring it up to 6.6 volts. At this point you mayuse an 8 volt charger. But a 12 volt battery reading less than 10 volts is still EXTREMEMLY discharged, and should be broughtback ASAP to avoid sulfation and decreased battery life. Please use a 12 volt charger, or make sure the charging system in yourapplication is strong enough, usually 14.6 volts is normal.TechMay 22, 2012 a 9:58 amReplyI have a 12V marine deep cycle battery which is marked 875 marine cranking amps, 675 cold cranking amps, and 125 amphours. I have been using the battery on my boat for about two years since I purchased it. It was charged every couple of monthsby either running the engine (a 9.9 HP outboard with an alternator which puts out less than 10 amps at full throttle) or by usinga regular car battery charger with a pulsating charge of 10 amps(duty cycle= 10 sec. on, 140 sec. off). It only serves the bilgepump when the boat is not in use, and the pump only runs a few times a day for a few seconds. After not checking it for abouttwo months, I found that my battery was not working (boat bilge was flooded) so I brought the battery out of the boat to myhouse. Prior to charging, it read about 6 volts on the meter, and it was low on water. Each cell had about 1/4 in. of the cellshowing, and I added about 4 oz. of distilled water to each cell. I charged it for about 50 hours with the 10 amp charger, andafter reading your article, I changed to a 1 amp charger. I now have access to a hydrometer, and I will stop the 1 amp chargetomorrow morning, and let the battery set for a while before checking with volt meter and hydrometer. The 10 amp charger still

reads about 9 amps on its meter when charging, and immediately after I disconnected it, the voltmeter showed 12.46 volts. Allcells were bubbling, and the battery was warm, about 100 F. What have I done wrong so far? Could I have damaged thebattery? Do you think it will recover from the deep discharge?Timothy LeeMay 26, 2012 a 7:27 amReply12.46 volts is good progress. You probably won‘t be able to see a full charge because of sulfation build up. It‘s like trying towash your hands while wearing gloves. I don‘t believe the battery is beyond repair, but I strongly recommend a desulfator orcharger with desulfation pulse mode (not voltage pulse, like some chargers do). Try a Battery MINDer or Pulse Tech unit.TechMay 29, 2012 a 8:18 amReplyI have four 110AH leisure batteries for my small hybrid solar system. The batteries are all 2yrs old and are not holding theircharge like they once did. I read somewhere that I could empty and wash them out then replace with a mixture of sulphuricacid(96%) with distilled water to the correct gravity, put them on a trickle charge for 36hrs and then they will be better thannew… Is this true? And if so, how can I be sure my mixture is correct? I do have a basic hydrometer. Many thanks!CarlosMay 28, 2012 a 12:16 pmReplyWe strongly advise against emptying out the electrolyte. Bad batteries are not a result of the electrolyte being “bad”, but usuallythere is a build up of sulfation on the plates in the cells. When exposed to oxygen, the sulfation will rapidly increase. Puttingnew acid sounds nice, but here‘s the problem. Sulfation is like trying to wash your hands while wearing gloves. You still won‘tsee a full charge. On top of that, if you remove the sulfation from the plates using a pulse charger/unit, then it will becomeelectrolyte and throw off your pH levels again when mixed with the new stuff.It‘s safer to simply use a de-sulfation unit like Battery MINDer or Pulse Tech for an extended period of time. That‘s what wedo.TechMay 29, 2012 a 8:56 amReplyI have recently purchased four new US Battery 12V Deep Cycle golf cart batteries for my 2006 Club Car, which has a 48Vmotor. I don\\\‘t drive the cart more than 1-2 miles on a given day but always recharge the batteries every day of use. The ClubCar charger is left plugged into the cart at all times the cart is not in use. I am getting an awful smell after the meter on thecharger drops to about 4 amps…on its way to zero on the charging cycle. I can hear the electrolyte bubbling inside the batteriesand they do not get hot whatsoever. Once the meter reads zero amps and the charging cycle has ended, the smell stops. Is thisnormal? Factory personnel tell me they will always smell when recharging…..but I have never experienced this with formerTrojan (Club Car) batteries. The local dealer says the smell should stop shortly…otherwise there may be a problem with one ofthe new batteries. My voltmeter shows 12.7v in each of the four batteries after charging.Gary MackJune 3, 2012 a 9:14 pmReplySome bubbling and smell of sulfur is normal for large flooded batteries. 12.7 volts is good voltage. As long as you monitor thewater levels, it sounds like everything else is fine. If the electrolyte boils over, or completely evaporates, that‘s a problem.TechJune 5, 2012 a 11:30 amReplyI have two deep cycle dp24 12 volt batteries. One is rated 685 CA 32degrees and the other is 505 ca 32 degrees, thefirst is rated at 140 minutes and the other is 120 minutes. Can these be connected in parallel without problems? Can they alsobe charged in parallel using one charger?ArtJune 5, 2012 a 5:08 amReplyYes, they can be paralleled together, but it‘s not advised. It will technically work. But charging and discharging will be un-even.There‘s no way around that. If you desperately need it, I say go ahead. But in the long term there may be some issues andmaybe shortened battery life as a result.TechJune 5, 2012 a 11:32 amReplySounds like a similar problem we have had with one of our vehicles. It is an F350 Truck with a box that has a communicationspackage. The truck has two batteries under the hood with green eyes. There is a third and much larger battery in the box thatpowers the inverters for the comms. Twice over the past 3.5 years the charging system has overheated the large battery until itfailed. Last time the battery boiled over and we had a mess to clean up. The charging system is powered by a shore line thatplugs into 125v wall receptacle. There has been some modifications to the systems and there is not sufficient info with thevehicle from the manufacturer that explains the 12 vots systems, but from what I understand the shore power charges all three

batteries. I assume I need to check if all three are charged by the same charger. What happens to MFLA batteries if they aremixed like this?JimMarch 27, 2013 a 4:32 amReplyGreat article, Learned much, but, and there is always a but, started looking at batteries and found the amp hour rating listed indifferent ways – examples:20 amp hour rate:5535 Amp Hour32 Min @ 10 AmpSo I am again confused about the true meaning of the amp hour.I think this is what I need to look for as I am looking for batteries for a trolling motor.Fred HarrisJune 9, 2012 a 7:13 amReplyAmp ratings are tricky. They really depend on two things: Draw amount, (Amps) and time. The first rating, 55 AH at 20 hoursmeans that during a 20 hour load time, it takes 55 amps to discharge the battery completely. I do not know what time frame thesecond rating is for, possible taken at 10 hours?. The third rating tells you if you draw a steady amount of 10 amps, the batteryshould last you 32 minutes. The first rating, 55 AH, is equivalent of 2.75 amps an hour. But if you bump it up to a rate of 10amps per hour, your duration is drastically cut to 32 minutes.Check out our battery load run time calculator to figure out what length of time a battery would give you under a load of yourchoice. Plus, there‘s also an article about Pukert‘s Law, which explains all about Battery Capacity. You should find that veryinformational.TechJune 12, 2012 a 12:10 pmReplyI live in a 3rd world country. Distilled water is not available here. Can I safely use the water out of my Katydyn Filter to addback water to my starter battery? The water going in is either rain water or river water; it is not treated chemically. If it is notacceptable for the battery, what are my options for adding water to the battery? Thanks in advance!TimJune 10, 2012 a 1:06 pmReplyDistilled water is best because there are no impurities. Using other water will technically work, but the battery will not performor last we long as it would otherwise. Having foreign contaminants and minerals will throw off the delicate chemistry of theelectrolyte, and throw of the pH levels, too. Filtered water will work better than rain water. But anything more than pure H20will negatively affect the battery.TechJune 12, 2012 a 12:18 pmReplyDistilled water is just captured steam. If you boil water and capture/cool the stream back into water, that‘s distilled water. Youcan pretty easily make your own with household supplies or even camping supplies. There are several methods out there.Google “How to distill water.”SamJuly 11, 2012 a 5:14 pmReplyThat‘s a very good idea. Thank you for sharing.TechJuly 12, 2012 a 8:47 amReplyMy question is,do you keep a 12volt battery(used for a golf trolley)constantly on charge,or remove from charge when fullycharged?.thanks.Graham BennettJune 12, 2012 a 3:14 amReplyIt really depends on the charger you use. If it is a manual constant current charger, then I would remove the batteries afterthey‘re fully charged. If the unit is a smart charger, like the 3-stage microprocessor controlled chargers we sell, then it‘s safe toleave on the battery forever. Keeping the battery in the “float mode” will ensure full charge at all times, which is the healthiestthing you can do for a battery.TechJune 12, 2012 a 1:31 pmReplyDear Sir,What is the best/correct proceedure when charging a 12v battery,used for a golf trolley.When fully charged,is best tokeep it on charge,or remove it from the power supply?. Thanks.

Graham BennettJune 14, 2012 a 1:28 amReplyThe best thing you can do for batteries is keep them in a fully charged state whenever possible. If your charging system will notovercharge, but will adjust and trickle down to a float charge, then it‘s safe to leave on indefinitely. If not, please remove afterit‘s done charging.TechJune 14, 2012 a 8:54 amReplyin a 24 volt system, batteries connected in series, if one battery happens to fail, should both batteries be changed regardless ofwhether or not the 2nd battery tests out fine? also, in the same system, if one would be required to boost the 24volt system froma another source being a 12 volt source… does one connect battery positive from boosting source to battery positive of batteryrequire boosting, negative to negative of only one battery?This seems like it could cause a problem as battery 1 is connected to battery 2 in series which means, battery + of one isconnected to battery – of the second, wouldn‘t boosting cause problems?? how does one go about doing this safely to himselfand the machine being boosted.JoshJune 15, 2012 a 10:36 amReplyIf one battery fails, it‘s recommended to replace both because battery banks composed of batteries of different ages will chargeand discharge unevenly. With the 12 volt boost, it looks like one battery is being discharged more than another. This is aproblem. The second battery, even though connected in series with the first, is untouched by the boost because the connectionsare only attached to the first battery. But having a 24 volt system, both batteries act as one single unit. Uneven charge levelswill cause early battery failure and poor performance. I would use the boost option as sparingly as possible.TechJune 15, 2012 a 2:57 pmReplyI have a question about battery charging from a solar panel. The solar charge controller uses a mosfet to act as a switch. If thevoltage on the battery increases to a certain level, then the mosfet opens and disconnects the solar panel. What happens if mysolar panel puts out 24 volts instead of 15-16 volts? Will the higher voltage but lower current of the panel cause any chargingproblems?Steve TannenbaumJune 22, 2012 a 4:18 pmReply12 volt solar panels can reach as high as 21-24 volts if the sunlight is direct. The controller should have specs regarding themaximum voltage input it can handle. Even though the controller is, like you said, a switch, it also lowers the charge voltage,too. Most of our controllers lower the voltage to a safe 14.4-14.8 volts. Therefore, 24 volts incoming from the panel is noproblem for the battery.TechJune 25, 2012 a 8:39 amReplyI BOUGHT A LIKE NEW HOVEROUND FOR 3.00 ON A GARAGE SALE. IT WASNOT USED MUCH AND THEBATTERIES WILL NOT CHARGE WITH ON BOARD CHARGER. I DID GET ONE TO CHARGE WILL ANOTHERLEAD ACID CHARGER ON 2 AMPS OVER NIGHT THE OTHER BATTERY SHOWS ONLY 7-8 VOLTS AND IS STILLCHARGING NOW 2 DAYS.CAN I DO ANYTHING TO BRING BACK THIS BATTERY? OR DO I NEED TO BY A NEW ON. I ADDED A LITTLEWATER TO THIS BATTERY EVEN THOUGH I KNEW IT DOESNT TAKE WATER WILL THIS HURT IT IT DOESNTCHARGE COMPLETELY ANYWAY.can i use lead acid batterys in this hoveround to get it going to test it?LET ME KNOW IF YOU CAN HELPTHANKSMARVMarvJune 26, 2012 a 7:20 amReply7-8 volts is extremely discharged. The batteries are probably beyond repair due to sulfation. If they cannot reach 12 volts,they‘re no use for them. I recommend replacing them. As far as which batteries to use, I suggest deep cycle batteries, not carbatteries. They can be flooded…but for mobility scooters its best to use sealed batteries like AGM or Gel.TechJune 26, 2012 a 10:55 amReplyIf you have a bunch of 12V deep cycle batteries paralleled (or groups of series 6‘s then paralleled to make 12V) – is it best toisolate each group so that at night the batteries are not fighting each other. I mean isolation as in commercial heavy duty battery

isolators. Is this much more necessary if the bank is not typically receiving a daily charge top up (i.e. solar)?KyleJune 30, 2012 a 12:29 amReplyIf the batteries in the bank are charging and discharging together, and they are of the same type, size, and age, then there is noneed to disconnect them. They act together as a single batery unit. But if the batteries are unevenly charged and/or differentcapacity, they will try to equalize and balance. This is can harm a small battery if connected to a large battery, which is notrecommended. Different age and type of the batteries can also cause inbalance.TechJuly 2, 2012 a 10:24 amReplyShouldn‘t this battery be dead? Why is it working?I just bought a 12v 7.2ah Valve regulated Lead acid battery for $5.00 I tested the volts and it‘s at 12.75 a sticker reads “TopCharge Date 4/26/2007I ran a motor from it for 2 minutes and it held up. I charged it and it took a charge. Should I run a cordless drill motor from it foras long as I can to see how long it last? Or should I leave well enough a lone?Thanks TrevorTrevorJuly 8, 2012 a 2:12 pmReply12.75 is good voltage. If the battery was kept maintained fully charged, there‘s no reason not to use it as long as there‘s nothingphysically wrong with the battery. Draining it down with lights, drills, motors is good, you should measure the voltage under theload to see if it holds up and doesn‘t crash. When you‘re done testing it, it‘s good to recharge it ASAP and keep it chargedwhen you‘re not using it.TechJuly 9, 2012 a 10:19 amReplyHiCan I charge a wet lead acid battery SLI in paralel whit a AGM deep cycle whit only one alternator?A relay disconnect de paralel when the motor is off.ThanksFranciscoJuly 10, 2012 a 11:37 amReplyFor a situation like yours, I recommend using a battery isolator switch, which can be used on up to 120 amp alternators toconveniently allow for adding a spare battery in your car, boat, or RV. The unit is a fully automatic switch that allows the enginealternator to charge 2 batteries, while keeping them electrically isolated from each other. This will prevent current flow fromone battery to another, thus allowing each battery to be an independent power source.You can see it here: http://www.batterystuff.com/battery-products/switches/Bi303303.htmlTechJuly 10, 2012 a 12:17 pmReplyI just bought a JL 50 scooter and the battery it came with is a12. Battery which came with the liquid which instructed me to putliquid into the cells and then cap it with the plastic cap plate that came with it and then charge fully before using. I filled it withthe liquid two days ago but have not been able to go buy the charger which I Plan on buying at wall art tomorrow. Last nightand one time today the battery cell cap has popped open on only one cell (the last one) loud enough for me to here it ( it is inthe same room with me). I am worried something is wrong, should I be concerned? Is this normal ? Is it because I squeezed thebottles when adding the liquid?MarissaJuly 13, 2012 a 6:49 pmReplyCongratulations on the new scooter!Squeezing the battery would not be a problem. It usually takes hours for the acid to become fully absorbed. The only cause Ican think of for the caps popping off is overheating. Is the battery in the garage? Did you install the vent tube that comes off theside?Something is causing the battery to build pressure, and it‘s not venting fast enough. If the liquid levels decrease, please adddistilled water. But other than that, everything else should be fine. Venting is normal, but caps popping off is not. You definitelydon‘t want that happening while on the road.TechJuly 16, 2012 a 10:00 amReplyMay I charge a 6v auto battery using a 12v (rated) solar panel?Bill

July 14, 2012 a 9:40 amReplyNo. This will be like trying to run a gasoline car on diesel. You can either use a 6 volt panel for the car battery, or series thebattery with another of identical specs to create 12 volts.TechJuly 16, 2012 a 10:09 amReplyA really helpful, first rate site. Thanks! My question relates to appropriate charging of an AGM (or alternatively, a Gel) batteryon a vintage, generator equipped car. The generator and standard regulator setup are inadequate to operating the car withheadlights AND, say, windshield wipers or heater blower. The set-point of the regulator has to be raised to 16 volts to avoidbattery drain whilst driving, and so after starting, and within about 5 minutes, as the voltage reaches 16, I switch on theheadlights to load the generator down to about 14.5 volts. After several hours drive, or when other loads are added, this voltagewill fall below 14 volts. Is this procedure good enough to maximize the life of an AGM or Gel battery? An alternator conversionis being considered. Comparing say a Delco 10Si with a Mitsubishi that might be used for tractor or marine purposes, whatshould I be careful about? I am thinking of the different battery applications, tractor, marine, etc, versus the Delco regulator of14.4 volts. Thanks.RogerJuly 22, 2012 a 9:07 amReply16 volts is too high and will damage a gel battery. 14.6 -14.8 volts for an AGM is just right. If you need to charge a gel battery, aregulator will be needed to keep the voltage from exceeding 14.2. An alternator would be a good idea. Regularly pumping 16volts in a battery will cause the internal resistance in the battery to spike and heat up. It‘s not recommended for the long run.TechJuly 23, 2012 a 4:07 pmReplyThank you for your great information. It always helps to read it rather than using guess work!I do have a question for you that I hope you can help with please.I have had our motorhome for nearly 2 years and it came with a couple of solar panels – one of which is rather large. Howeverwe have had a couple of problems with cooked batteries! Basically, we discovered our battery was being cooked by one of oursolar panels as the regulator was not working. We got that sorted and replaced the very smelly leisure battery. But just recentlythe same thing happened again and we discovered that our very large solar panel didn‘t have a regulator on it at all. We realisedvery quickly and disconnected the battery which was beginning to sulphar up and smell. We have since added a regulator andalthough the battery was able to be cleaned up we are finding that it now will take a decent charge but is only holding thatcharge for about 45 minutes. So we have 2 great solar panels and no holding charge. Do you think that this is due to thedamaged battery or could it be something else? It is a sealed battery and so we cannot tell what state it is in internally. Thankyou.SteveJuly 25, 2012 a 2:18 pmReplyIf the issue was sulfation, then the solution would be to try to restore the battery with an on-board pulse de-sulfator. But if thebatteries have been over-charged, and they drain very quickly, then there really is nothing else you can do. Overcharging candramatically age a battery rapidly.Can you provide some voltage readings? Say, one at rest. While on the charger. And finally, a reading 45 minutes after off thecharger. With these numbers, I can more accurately diagnose the battery.TechJuly 26, 2012 a 8:35 amReplyTHANK YOU FOR SHARING YOUR KNOWLEDGE! WOW! I have been working with batteries for years, yet never reallyunderstood their differences, much less how to match them with various applications. Here I have been buying based on thehighest amp/hr AND CCA, when I should be looking harder at one or the other. And now there‘s an AGM???Okay, ….a question:The GPS/Fish Finder on our boat uses around one-third of an amp. My typical day of ocean fishing is between 8 and 10 hours. Ido not like it on the starting battery and am looking for options.The first question is AGM or a small gel cell? I am looking to understand the balance between them, in particularly, the lesserchance/lower cost of replacing it in the event I trash it, …which I am convinced is destiny – or the higher cost of a gel that I willnot trash. (While I think I am very easy on batteries, evidence shows they do not seem to like me.) So, is it just math, or arethere other considerations I should be looking at?If using an AGM, the YT4L-BS will give me 9 hours of GPS. Correct? Or should I be looking at double that size, like theYT6.5L 12v AGM? I just cannot see spending $140 for something a 41 battery will do just as well for.Prior to reading your pages, I had heard of AGMs, but the information was skewed. I was told they are just like gel cells, whichI now know is only a half-truth. I can clearly see the differences over wet and gel, but I am most attracted to the lowreplacement cost if I, indeed, trash it.Which one do you recommend?

Again, thank you for the site, …and I welcome your sagacity.Cpt CrunchJuly 30, 2012 a 12:42 amReplyAGM batteries can be recharged with any battery charger. Gels are more fragile, and they need a charger with a safe voltageprofile for charging. Gel batteries can be discharged further without the damage it would cause an AGM. We recommend nomore than 50% for AGM. The Gel can go as much as 80% discharged.For your GPS/Fish Finder, I recommend a deep cycle battery. The YT4L and YT6.5L are motorcycle starting batteries. Irecommend a sealed lead acid deep cycle battery. Having one at least 8 AH in capacity should give you 10 hour of safe runtimegiven the 300 mAh draw. This is what I recommend:http://www.batterystuff.com/batteries/upc-telecom/sla-1280.htmlTechJuly 30, 2012 a 3:17 pmReplyI have an old (‘85) Honda ATV. After some reading (obviously not enough)I purchased a gel cell battery that was advertized asappropriate for my ATV. It did not take long for the battery to reach a point where it would light lights but not turn over theelectric starter. After more reading, it would seem that the alternater would need some “adjusting” to keep this battery charged.I can find many references to external chargers, however I have, so far, been unable to find any information on what needs tobe done to upgrade the charging system of the ATV for gel. Any help here?BillAugust 3, 2012 a 2:01 pmReplyWe do not sell anything that would regulate an alternator to a safe voltage for Gel batteries (no more than 14.2 volts). I imagineit would be costly. It‘s easier to simply purchase an AGM battery for the ATV and not have to worry about chargingdifferences.TechAugust 3, 2012 a 4:07 pmReplyHi, First of all I want to say that your tutorials have been very useful for me and I have learned very much.I have an off grid house that I power with four 12V 245AH 8D AGM batteries wired in Parallel which are connected to axantrex 3000W sine wave inverter/charger. I have a xantrex link pro battery monitor that has a programable alarm relay that Ihave set to start the generator when the batteries get down to 55% state of charge and to turn off again at 85%. occasionally Iturn the generator on manually to bring the batteries up to 100% charge to synchronize the monitor. I just set the system up afew weeks ago and it is working very well so far. I am not there very often but whenever I check on it, the batteries are withinrange and the generator runs for 4 or 5 hours a week. The only thing running while I am gone is the refrigerator and a half dozen7w led lights that I have come on after dark. I don‘t have any other source to charge the batteries yet (solar or wind).I have a couple of questions:Do you think this system will work well in terms of longevity? Is there something I should be doing differently, such as settingup the monitor to keep the batteries at a different state of charge (more or less discharge)? The reason I don‘t bring them to100% every time is that the generator needs to run for quite a long time to get the extra 10-15% into the batteries and it seemslike a waste of fuel.Second, if I had an always on wireless internet connection, do you know of a way that I could monitor the battery conditionfrom far away via the internet? So that I would know if there was a problem with the generator not coming on. I don‘t know ifthere is a battery monitor available set up to do that. Any ideas you might have would be geatly appreciated.Thank you.BobAugust 11, 2012 a 7:17 pmReplyhi,i have a solar system & i am using a device that measures the voltage of the batteries and send it through a serial port to thecomputer, that can show me the health at anytime of the day.i have 8 batteries connected in parallel, and the problem that i am trying to think of a solution is that the measuring device istreating the 8 batteries as one, and gives me a single reading. But in order for my monitoring project to work, i want to be ableto measure each battery alone, even when they are connected in parallel together…I know this sounds impossible, but I still need to think of all possibilities.Anyone with any clues would be very helpful.Thanks.BobAugust 14, 2012 a 8:16 pmReplyAny technical questions can be emailed directly to Tech@batterystuff.com for the fastest response.To answer, at least the best I can, I would personally hook up the tester that you are using to an 8 point switch, where each ofthe 8 modes were connected to one of the batteries directly. You could then switch the connection on the monitor to each

battery individually, even though they are all hooked up together. The only real downside to this would be that if your device isone of the more accurate types, then it will be thrown off by resetting it on each battery and will cease to be as accurate. On theother hand, if it is not a super accurate one, then I wouldn‘t bother setting it up this way anyways. So while its not completelyimpossible, its a bit of a catch 22. The accurate one will cease to be so, and the not as accurate one falls in the ‘why bother’catergory. Hope that helps! :)Jeremy FearAugust 15, 2012 a 11:16 amReplyHiI have (8) x 6V x 125AH deep cycle batteries producing 24V in a series/parallel configcharged by a 250W x 24V solar panel,powering a 24V fridge/freezer 24/7 drawing 2A when running.Am i correct in assuming my total stored AH capacity should be sufficient to run the fridgewith minimal sunlight for a few weeks.CheersMaxMax WilliamsAugust 16, 2012 a 2:52 amReplyAs long as you rpanels recieve at least 5.5 hours of direct sunlight on the panel then you should be good. If you have anyfurther technical questions, please email them to Tech@batterystuff.comJeremy FearAugust 16, 2012 a 9:43 amReplyhello i have 8 deep cycle battery 12v 200Ah connected series/parallel to supply a ups system and it charged by acostant charger52.5 V 35A its working abot 18 month every day about 6hr on the UPS and now begin loose its capacity when i check thevoltage for each battery while the charger working some of them give 13,4v and other 12.66 and 12.9 so it the sulfated or needfor reacharging with a smart charger .thanksQusayAugust 19, 2012 a 6:52 pmReplyI don‘t know what the load is, but for a 48 volt system the charger seems a little too low if it‘s charging at 52.5 V. It should be56 V or so under the bulk charge mode. For float, 52.5 is okay. I‘m not sure what your question is about.If the batteries are individually reading different voltages, that‘s not good for the system. Are the batteries the same age? 13.4 vis a little high but good full charge, while 12.9 v sounds just about right. 12.66 v could use more charge. If it‘s not able to reachany higher voltage, sulfation is a good cause of that. An onboard de-sulfator like the Power Pulse or ODB from BatteryMINDer would be recommended to fix that battery. No need to disconnect it from the others or change your system.TechAugust 20, 2012 a 11:47 amReplythanks alot for your assistant1- my battery have the same age2- i cant increase the charger voltage because its max volt is 52.5 also till now i dont try another charger or charge each batteryindividually3- these readings for each battery but while they connected to the charger and for example when im add all the reading (13.4+12.66+12.9+13.54) its equal to 52.5 which is the charger voltage and when im disconnect the charger and after 1 hrbattery reading is ( 12.7 , 12.5 , 12.7 , 12.6 ) i think battery No 1 and 4 prevent the voltage to rais in battery 2 and 3 so theycannot charge fully , also at the first 8 month all the battery have the same reading when charging .do recommend individually charging for each battery to force it reach to 13.6 v and accept current , like using 48 v charger with4 bank or its no problem to use 48 v charger with one bank also if i want to desulfate it it is better to use obd-12 for each on oruse obd 48 for each 4 batteriesalso what is the recomended methode to charge and maintain this system to get maximum life for the batteries .thanks & best regardQusayAugust 20, 2012 a 2:35 pmReplyA 4 bank 48 volt charger would charge the batteries individually, which may solve the problem. 52.5 volts is good if thebatteries are fully charged. But since they are not all charged, I recommend the charge rate should be higher for the two tocharge up. If you use the OBD-12, you‘ll need one for each battery. Otherwise, you can use a single OBD-48 for all fourbatteries in series.TechAugust 21, 2012 a 7:50 amReply

thanks to helping me to solve the problem and thanks for the site which give this amount of data for users , really great site andgreat staffthanks again with my best regardsQusayAugust 21, 2012 a 11:01 amReplyHi, just got a new kirkland battery and it has the 6 cells under the cap. Not all of the cells have liquid in them to the top. is thisnormal for some cells to have more liquid than others, should they all be filled to the top? I could not see any fill lines as towhere the level should be. thanksJeffAugust 27, 2012 a 5:01 pmReplyYes, the cells should be balanced, even as far as liquid levels. Please only use distilled water. They do not need to be filled tothe rim, but definitely the plates should never be exposed. If this happens, the plates react with the oxygen in the air and formsulfation rapidly. I hope this answers your question.TechAugust 28, 2012 a 10:24 amReplyI have new replacement 4 × 12v 18 ah deep cycle agm batteries wired in series for an e-bike, the 48 v charger charges the bankat around 54-55 v, Now,the original batteries performed the last 2 years as expected for 300- 400 cycles with good range , butthese new replacement batteries are failing within weeks, less than 30% range than originals. When testing the charging voltagegoing to each individual battery in series , it varies from 14.1 V- 15.9 V from one battery to the next. and under a timed load teston each charged battery, they range from 2 min to 55 min before dropping below 11.5 /cell. Are the batteries poorly constructedor is it a charger issue? Thanks for any insight you can provide.Will HelbichAugust 31, 2012 a 3:38 pmReplyHow much was the load amount for the test? 15.9 volts is on the high side as far as charging goes.TechSeptember 4, 2012 a 3:10 pmReplyThis is a philosophical comment. Lead-acid batteries suffer from self discharge. Batteries actually spend overwhelmingly mostof the time not on charge but doing absolutely nothing at all. This is what causes sulfation. So what do the experts recommendbattery users do? Treat the sulfation. A hundred year old cure! How about treating the battery with something that stops the selfdischarge?John FetterSeptember 6, 2012 a 12:52 amReplyKeeping a battery on a trickle charger will prevent self discharge. Beyond that, asking a battery not to self discharge is likeasking a person not to age. It‘s a chemical issue, and healthy batteries will self discharge at a lower rate than older batterie orcheap batteries made from lesser quality materials.TechSeptember 6, 2012 a 8:48 amReplyWhen using a deep cycle battery in a Solar system, using DC 12 volt lights. Is there a way to automatically shut off the lightsbefore it discharges the battery too far?BobSeptember 7, 2012 a 11:38 pmReplyYes, you would need a battery disconnect or a power switch. Priority Start and Battery Guard are two brands that will do thisautomatically. We sell these in our battery accessories category.TechSeptember 10, 2012 a 8:42 amReplyI have an electric 2-wheel scooter that my wife uses. It has 3-batteries linked together. How do I hook-up the cables on mybattery charger to charge this bank of 3-batteries?Charles WehlandSeptember 8, 2012 a 1:34 pmReplyIt depends entirely if the batteries are suppose to be in series or parallel. The answer to this question depends if the scooter runsoff 12 volts, or 36 volts. But the surest place to connect your charger to are the same terminals that the scooter‘s motor isconnected to in order to run.Tech

September 10, 2012 a 8:57 amReplyHi James, thank you for the information and excellent explanations! How can I figure out what type of battery in my car (2007BMW X3)? The battery is a sealed maintenance free battery. It’s the original battery. The part number is S: 61 21 8 385 398,and the label says it’s 90 AH and 720 CCA, but no manufacture name on it though. I called couple of BMW dealers, but theydidn’t know. Hopefully you can help me out. Thanks in advance!BoSeptember 11, 2012 a 1:53 pmReplySounds like an AGM or a VRLA battery. Both are different types of lead acid batteries, the sealed ones as apposed to theconventional flooded type. It‘s not going to be a gel, I can almost guarantee that. Gel batteries are completely sealed. If thereany ventilation or even vent slits on the top of the case, then it‘s not a gel. That‘s good too, because gel batteries don‘t makegood starting batteries. They‘re fragile.TechSeptember 11, 2012 a 2:20 pmReplyThank you very much for your answer. I have a battery charger, and I need to choose one of Standard, AGM, and GEL batterytype. Which type should I select?BoSeptember 12, 2012 a 6:42 amReplyGel is the safest, because it uses the lowest charging voltage of the three. If you are not sure, the gel setting is always a safeoption. Otherwise, if you think it‘s an AGM (check to make sure there are ventilation slots to confirm it‘s not a gel) then use theAGM setting.TechSeptember 12, 2012 a 7:45 amReplythis rlly helped me in my auto electrical classAustinSeptember 17, 2012 a 11:41 amReplyit helped me alot but google‘s betterMarkSeptember 17, 2012 a 11:44 amReplyWhat did you find that more helpful? Lease share it with us.TechSeptember 17, 2012 a 12:18 pmReplyHi all,Current setup:1) Two UPSs. Both are independent systems.2) Both are identical; Manufacturer: Delta; Model:J-Series 7 KVA. Each capacity: 5000 Watt, 230 Volt AC.3) Each has 20 numbers of 12 Volt 26 AH batteries connected in series for a 240 Volt DC, 26 AH battery bank.Objective:a)Design a battery bank in such a way that even if one battery fails, the bank would still be operational and keep the UPSrunning until the failed battery is replaced.b)Try reconfiguring existing battery bank so that cost is minimized.Proposed setup:1)Instead of two identical but separate battery banks as configured now, reconfigure the 40 batteries in one battery bank.2)Batteries will be connected in series and also in parallel as listed in the diagram.3)Two batteries will be connected in parallel to form one 12 Volt 52 AH parallel battery bank pair. Twenty such pairs will belinked in series to form one 240 Volt DC 52 AH bank.4)Connect both UPSs to this one battery bank.5)The 230 Volt AC “Output” of the UPSs would remain independent as they are now.Attached Diagram:Both the current setup as well as the proposed setup are illustrated.(No change in the independent “Outputs” of the two UPSs. The 230 Volt AC “Output” of the two UPSs would remain the same(as independent outputs) in the proposed setup as they are now in the existing setup.)Advantages:1)When any one battery fails, the entire bank would still be operational. (Hence, the UPSs will not fail.)2)So long as “both” batteries connected in any parallel pair do not fail, the bank would still be operational.Question:

1)Would the battery charging circuits in each UPS somehow interfere with each other?2)Are there other issues and/or disadvantages in the proposed system that are overlooked?When electrical power is On, would the battery charging systems in each UPS interfere with each other when charging thesingle battery bank? In other words, currently just as one UPS charges its own battery bank, would the two UPSs charge thesingle common battery bank without issues?We would be very thankful to you if you can please give us your valuable feedback on our proposed battery bank set up.Selvan Albert.Selvan AlbertSeptember 19, 2012 a 7:26 amReplyI want to increase the voltage of 2 batteries from 24V to 180V. Is it possible?Ameya PawarSeptember 26, 2012 a 4:55 amReplyThere are some step up converters to increase voltages, but we do not sell them. Additionally, I think it may be hard to find onethat will step up to 180 volts.TechSeptember 26, 2012 a 9:26 amReplyThank you for your opinion….I would like to use an electric golf cart for in-town transportation in a small town in the San JuanMountains of Colorado, year around. I am a teacher and typically only drive it back and forth once or twice a day, about onemile each way. 1st question: It can be very cold here on winter mornings, (-20 degrees and more),but then warm-up to 30degrees on the same day, is there a battery that can handle the temperature range, and still have a reasonable life length? 2ndquestion: I have a solar panel that I could place on the roof, get a charge controller, and have the batteries always tricklecharging, how will that effect the battery life? I have a 36 volt charger that came with the cart. The cart is perhaps 20 years old.The batteries it came with were all exhausted, I took them to a recycler. I was thinking of spending the 150.00 each ( includingcore fee) for 6 batteries, and stop driving my gas vehicle. I‘d appreciate some advice.Adam JohnsonSeptember 27, 2012 a 7:00 amReplyFor the greatest range of operating temperature, the gel batteries would work the best. For a solar panel, you would either needa single 36 volt panel, or 3 12 volt panels in series. That‘s a good idea if you want to see the longest lifespan from the batteries.The charge controller, make sure it‘s safe for gel batteries, which require a slightly lower voltage charge than most otherbatteries need. We sell Trojan T-105 6 volt batteries for $139 each. No core needed.TechSeptember 27, 2012 a 8:17 amReplyGreat article. I learned more than I‘ve ever known about batteries, but I still don‘t know much.I am wondering, I recently purchased a year round ice fishing house / camper. I‘m looking at batteries now and am leaningtowards an AGM. Is that what you would recommend? Again, this battery will be used year round. Freezing cold when it sitsfor 4-5 days at a time without being used, then it will be used on the weekends when I go fishing. Then during the summer itwill be used in the heat.I‘ve also seen a couple mentions of solar chargers. I do have a generator that i plan to use to recharge the battery whennecessary, but am wondering if it would make sense to leave a solar charger hooked up to the battery constantly. The locationof the battery in the house would make it very simple to hook a solar charger up and have it mounted either directly in thewindow, or just outside attached to the side of the camper/fish house. Then even when in use, the battery would be charging,right?Thanks in advance for any response.MattOctober 9, 2012 a 4:31 pmReplyFor extreme temperatures, the Gel batteries are the best. They also have the slowest discharge rate. Having a solar panel is agreat idea, and perfectly safe even if a generator is on or you are using the batteries, if you are also using a solar controller(which regulate safe charge voltage levels, and prevents back feed into the panel). But yes, if a solar panel is receiving sunlight,the battery will also be charging as well.TechOctober 11, 2012 a 9:28 amReplyGreat Article !For what it‘s worth. I use NorthStar pure lead AGM batteries. They have the widest operating temperature range (-40 deg F to+ 149 deg F) and have a two year shelf life. Never saw a gel battery with that type of operating temperatures. I have one in inmy truck. Never a minutes worth of problem.Tim

January 15, 2013 a 12:10 pmReplyPure lead vs recycled lead does make a difference in performance. NorthStar batteries sounds like good batteries.TechJanuary 15, 2013 a 1:19 pmReplyThank you for your great work! I have learned a lot.I have a Die Hard 1150: 20ah AGM power pack. As per your explanations, I leave it plugged in because it has an integratedsmart charger that is supposed to provide a safe float charge to maintain the battery‘s health. I have two questions relative tothis:1. Is it normal that the battery is slightly warm to the touch when it is plugged, has reached 100% and is receiving amaintenance charge?2. Are dangerous gases given off while the battery is plugged in and receiving a trickle charge? My battery is plugged in in thebasement workshop in a fairly large house.Thanks for any information you can provide and take care.PeterPeterOctober 14, 2012 a 3:22 pmReplyIf the battery is warm, it‘s because there is more resistance in the battery internally than normal. There is probably a goodamount of sulfate crystals on the plates in the cells, which would cause the charger to work harder to maintain the float mode.Sulfation robs the battery of power, but can be reserved with de-sulfation units and chargers.Gassing should not be an issue if the battery is healthy. Only significant over-charging should cause an AGM to ventexcessively.TechOctober 15, 2012 a 1:14 pmReplyI have a Toyota Coaster bus which is fitted out as a motor-home. The vehicle was manufactured with a 24 volt electricalsystem, which uses two batteries in series, of 12 volts each. I have outlined a description of the auxiliary electrical systembelow, but my basic question is, how can I know how depleted my auxiliary batteries are at the end of a day in which therefrigerator has been working for a long time?I think the basic rule is that the batteries should not be discharged below 50% of their capacity, but what reliable method can Iuse to determine when they have reached this point? There are two auxiliary 12 volt batteries in series, each 120 amp-hour, toprovide power for the “house system” – namely refrigerator, lights, water-pump, and various 12 volt power outlets. Therefrigerator is the major user of battery power, because it is a compressor fridge which uses the equivalent of 12 volts 8amps(i.e.96 watts) while it is running, and it runs for approximately 8 to 12 hours in each 24 hour period depending on how hot theweather is. The auxiliary batteries are charged by two solar panels of 80 watts each, and receive additional charging from thevehicle alternator when the engine is running. There is a battery isolator which automatically disconnects the auxiliary batteriesfrom the vehicle electrical system when the engine is not running. The voltage regulator for the solar panel charging systemprovides a constant display for the auxiliary system, including the auxiliary battery voltage. I have been in the habit of checkingthe voltage last thing at night, and first thing in the morning, to find how much power the fridge has taken from the batteries. Ifthe night time voltage is below 24.8volts, then the morning reading is below 24.0 volts. The problem is that if we have not donemuch driving on a particular day, and the solar panels have not done much charging because of cloudy weather, the night-timevoltage may only be 24.2 volts, and the morning voltage not much above 23 volts. If the battery is at 24.2 volts when the fridgeis not running, then when the fridge starts running the voltage reading drops down to about 23.5 volts. And so my questionremains, what is the lowest acceptable voltage for my auxiliary battery system, so that the batteries are not damaged by beingdischarged too much. Thank you for reading through a long and detailed letter, but I wanted to provide sufficient backgroundinformation.Wilfred KubeOctober 22, 2012 a 4:35 pmReplyResting voltage of 24.4 volts is 50%. When you reach this point, stop using the batteries until you can recharge them again.TechOctober 23, 2012 a 10:50 amReplyThank you very much for your helpful site,and for your prompt reply to my query.Wilfred KubeOctober 24, 2012 a 2:13 pmReplyI do have the same system as Wilfred, although I use a Tripp Lite to invert current from 12V to 110V (2,400 Watts)I have always used 3 cheap regular truck size batteries, charged by the alternator and, with the almost every WE driving, hadno problem running everything for 3 years without having to charge the batteries with an external chargerRecently, to lower the weight, I bought 2 trojan deep cycle batteries 225 that almost totalled the same Amp as the 3 previous

onesTo my surprise, these batteries have gone dead last week after 6 months of use, although well maintained as far as water andregular charging through the alternatorThe Tripp Lite works fine and we always avoid to use the battery lower than the yellow and red lights which indicate a batteryload of 50 %We did have a 2 minutes run on red light 2 weeks ago (as much as 80% discharge) and to prevent any further problem Irecharged the batteries with an external charger together for 20 hours (for the first time in the last 10 years); the chargerindicated 14V at the end of the charging process.Unfortunately, on a trip last week I lost power faster then ever and ended up having to only use the refrigerator while driving,forgetting about the water pump or the coffee maker; I tried to recharge the batteries since then but the charger wont go over 10volts and goes down to 8 and 7 after 10 hoursMy question: since these trojan batteries are very expensive where I live (Peru) should I invest in a charger, what kind, andshould I charge the batteries everyday from my house? The car is in the street and I cant go check every 2 hours what thevoltage is, so is there a charging process that is safe, guaranteed on the long term for these batteries?Once again this is the full description of my configuration:bus sprinter with alternator of 100 Ampstarter battery of 120 Amp2 trojan deep cycle 225 130 amp each output 12Vone tripp lite inverter 12-120V 2,400 WattsThank you so much for your answer which should interest many people like me who just want to understand how to run asimple 3 or 4 devices in their camperYves Van DammeFebruary 9, 2013 a 1:22 pmReplyIt sounds to me like your current charger is probably fine but the batteries may be defective or had their life significantlyreduced when they were overly discharged those 2 weeks ago.TechFebruary 11, 2013 a 11:13 amReplyThank you for your article, I have a question. I bought a 2 month old (STICKER ON IT) battery from junkyard, outside cell waspunctured in a crash, looked inside all electrolyte was gone from the one cell. I repaired the plastic casing,it could now holdliquid safely. Could i add electrolite from an old battery or would that have too many sulfites , it would be better to get amotorcycles worth at autozone? I am going to turn in my old battery anyway as it is a core charge… What do you think?David CuneoOctober 26, 2012 a 12:36 amReplyThe moment oxygen hits activated plates in a cell, sulfation will form rapidly. My opinion is that it's not worth the effort or therisk. I recommend buying a new battery. Even if you were able to restore this one a bit, I doubt it will last very long and itwould not be safe as the internal resistance when charging will be greater than a healthy battery, which you will risk the batteryoverheating as a result.TechOctober 26, 2012 a 8:33 amReply”… An amp hour (AH) is a rating usually found on deep cycle batteries. The standard rating is an Amp rating taken for 20Hours. What this means, say for a 100 AH rated battery is this: Draw from the battery for 20 hours and it will provide a total of100 amps …”Should say …”… and it will provide a total of 100 amp-hours …”GregOctober 28, 2012 a 6:22 pmReplyThank you for the suggestion. We will make the change.TechOctober 29, 2012 a 9:21 amReplyMy AGM 100amps battery for UPS is acting strange it gains full charge with 30-50 mins while it also discharges with 30-40mins, my UPS is charging the battery on 10-12 amps. Any HelpFawadNovember 19, 2012 a 12:09 amReplyWhat is the amount of draw (load) on the battery when its in use?TechNovember 19, 2012 a 2:42 pm

ReplyI don know exactly but its has a Samsung 42” Plasma Tv and and small Satellite receiver, that‘s all. And with the same load itgave me a Backup time of almost 2 to three hours.FawadNovember 20, 2012 a 3:25 amReplyIf I understand you correctly, your battery isn‘t lasting as long as it used to, and it charges quickly, too? Short charge/dischargeperiods? Sounds like the battery has sulfate crystal buildup on the plates. Sulfation causes batteries to age quickly. Refer to ourother technical articles about how to remove sulfation.TechNovember 20, 2012 a 4:29 pmReplyi bought a 12Volt battery 22months back with inverter for my desktop computer only. It reads GT-2100 C20 210AH. It‘s a leadacid battery. The dealer told me that i can use it for 10 and half hours for to power my computer only. from internet i came toknow that one should not fully discharge a battery. i till date only once i used it up to 9 1/2 hours. never seen ‘battery low’blinking any time till date. I always carefully kept the water level full by regularly checking the level indicators. On an average iuse the battery up to 7 to 9 hrs these days because of big power cuts here and see it charged fully immediately when powercomes. One problem is that if i use the battery for 9 hours then there has to be continuous power supply for at least up to 8hours(+minutes) to get fully recharged. but here they are supplying power only on alternate hours. i.e, one hour power supply –one hour power cut – one hour power supply. and that too during the night only. during day time only for four hours power ingiven- morning 8to10 and evening 4to6. rest all day power cut. only in the past 3 months power supply became like this. i havebeen forced to use my battery very carefully and judiciously. My questions is will it affect my battery life by leaving it to becharged in alternate hours?.(i don‘t use it during night while being charged). i am really worried. we have abundant sunshinehere. so i am willing to explore the possibilities to charge it using a solar panel. i want to know the maximum wattage or voltageshould i supply to charge it in the minimum amount of time possible. tell me this much wattage up to this much hour. here wehave 10~ hours of bright sunshine. please help.MuruganNovember 19, 2012 a 11:09 pmReplyIt‘s okay if the battery is receiving charge during irregular intervals. It‘s not the best situation, but it‘s not going to destroy thebattery immediately. The truth is, the battery is going to build sulfation when its in a discharged state. Re-charging it will reversethis. That‘s good practice, but I understand if your situation prevents you from doing that in the best way possible.If you‘re looking for solar charging, the largest panel I recommend you can use to safely recharge the battery in the quickesttime is a 900 Watt solar panel. This will charge at a rate of 73 amps per hour (35% of battery capacity). Less is fine, but nomore for safe re-charging.TechNovember 20, 2012 a 11:58 amReplythank you very much indeed. Have a nice day back there.MuruganNovember 20, 2012 a 9:02 pmReply(continued…)I am using a 17 inch CRT monitor which consumes 80W power. Here in India we use 220V Ac for our appliances.MuruganNovember 20, 2012 a 1:51 amReplyIs it possible a Low maintanance Lead Acid can charge and discharge Simultanously ?NandDecember 4, 2012 a 1:36 amReplyNo. If you are charging a battery and then you use it at the same time, the charger will attempt to supply the load. Dependingwhat the load amount is, and if the charger can supply it, the battery may be charged at a lower rate or not at all and startdischarging instead.TechDecember 4, 2012 a 8:08 amReplyI purchased a used boat in 2009, it has 2 identical West Marine starter batteries 650 CCA with a Perko 3 way switch, 1, 2 bothor off). I‘ve never charged these batteries other than while running my boat, which is probably less than 50 hours per year. Theengine is a 175HP Suzuki, with a 44 amp alternator. I feel like I‘m running on borrowed time and want to replace these batterieswith AGMs. Should I go with 2 starter type batteries or 1 starter and 1 house? While boat is running is the alt charging bothbattery at the same time or does it follow the path of the Perko switch? Thanks, great site.Andy

December 16, 2012 a 2:09 pmReplySince the batteries will be connected together via switch, I recommend using two of the same battery types and sizes.Therefore, if the batteries are used to start the engine I recommend two starting batteries. I recommend a deep cycle battery ifyou need 12v power while the engine is off.TechDecember 17, 2012 a 10:19 amReplyI use 4 – 12 volt dcm0035 interstate batteries hooked up to 48 volt configuration to power my pedicab. I have 2 sets-8 batteriestotal. They have had 11 months of being drained to approx 12 volts on the meter 3+ times a week. I use 2 noco gen 4 chargers.Mostly in the 10 amp mode….but sometimes doubled up on one battery set. Weather conditions from 35 – 110 F. How can Idetermine how much life is left? Besides the obvious based on how long they run before being drained. It seems they are atabout 50% of new. Also…does my charger do a real 100% chargeMikeDecember 17, 2012 a 7:34 pmReplyThere is no magical formula to predict the length of life remaining in a battery. Yes, the Gen 4 charger should bring the batteriesto full charge before entering the gentle float mode on/off cycle. 12.0v on the meter is more than 50% discharge, which is morethan we recommend for optimal performance.TechDecember 18, 2012 a 9:02 amReplyi have 4 batteries ps 1272 fs 12 volt 7.2 amp batteries were stolen how can i wire theser my bike?EdDecember 26, 2012 a 2:22 pmReplyIs your bike a 12v, 24v, or 48v electric motor?TechDecember 28, 2012 a 8:32 amReplyi have 3 sb 12100-s 12 volt 10 amp batteries for my bike which were stolen how do i wire the new ones?EdDecember 26, 2012 a 2:29 pmReplyIs your bike have a 12v or 36v electric motor?TechDecember 28, 2012 a 8:36 amReplyHi,Very informative article, thank you. I have a problem with my camper van, 24 volt system for the truck, 25 amp alternator,fridge in the house on the truck that draws current from the 2 × 12 volt in series truck batteries. When ignition is off, the fridgestop drawing current. However, the truck batteries constantly run flat during driving, all well while I drive (diesel truck), butnext morning the truck batteries are almost flat. The camper van house has it‘s own 12 volt battery, charged from solar, itperforms OK. Currently the 12 volt fridge element draws amps from the second 12 volt truck battery, this implies that the fridgeuses the power from the battery, not directly from the alternator. Is it possible that the power outflow from the battery is morethan the charge inflow into the battery?. How many Amps can a battery continuously take while charging?. I now think I musttap the 24 volt directly from the alternator, then put it through a rectifier to get 12 volt, and then onwards to the fridge. This willleave the truck batteries free to charge at will without being drained by the fridge. If the truck batteries can only charge at say 6amps, while the fridge draws 10 amps, the current set up will always discharge and leave me with flat batteries. Am I correct inmy reasoning?. Please advise asap, Many thanks, LouwLouw Penni NgJanuary 5, 2013 a 1:18 pmReplyThere is no limit to what a battery can or cannot accept. A battery cannot say ‘no’ to charge. However, there is a safe range, upto 25% of the battery capacity, should be the max amperage charge rate. For a 50 AH battery, that would be a max of 12.5amps per hour. Alternators usually don‘t have problems with overcharging, because of the electronic control unit.It sounds to me like you have a 24 volt battery system, but a 12 volt alternator. It seems like the fridge only takes 12 volts torun. What part of your system actually draws from 24 volts?TechJanuary 7, 2013 a 9:02 amReplyRE; Can anyone please help? Scooter battery problem, will not take a charge.It appears that there may not be anything wrong with my batteries. I was told that the batteries must be charged every month or

two or sulfation would set in. But the batteries not excepting a charge after 4 months was concerning. With no answers Idecided to drain the batteries of two scooters by running the motors with the throttle on full and turning the lights on. Howeverafter 5 hours of constant running the scooters meters were still showing full and the volts where at 48.7 and my volt meter wasshowing 48.6 volts. After 5 hour only dropped 2 volts while protection shutoff is 42 volt. The next day I charged the batteriesand yes they took a good charge, 7 hours and still taking a charge when I left for the day (I have them on a 12 hour timer).These Chaowei deep cycle gel batteries must be very good with little self discharge to not except a charge for 4 months.Garry McdonaldJanuary 6, 2013 a 2:43 pmReplyI‘m glad your batteries are fine now. But for the future, it‘s not necessary to discharge these batteries down. They are not likeNiCD batteries, there is no ‘memory effect’ or need to cycle charges. Batteries that are fully charged for a 48v system shouldgive you 51.2 volts or more.TechJanuary 7, 2013 a 9:08 amReplyVery Informative! (I assume 1 to be the highest rating). I have an ‘85 Ford class C motorhome with 2-12v batteries. Not sure ifthey‘re connected in series or parallel. It has a single alternator and a separate voltage regulator. With the engine running, onebattery reads 12.4v, the other reads 16v. I assume this means the alternator is trying to charge this battery more? I first thoughtthe regulator was bad & replaced it. At that time, one battery was reading 16.4v & the other 16.2. I discovered I had bought thewrong regulator, so I bought a second one. It read 16v and 17v. I put the original regulator back in, leading to my assumptionthat one battery won‘t hold a charge and the alternator/regulator is trying “harder” to charge it. The batteries were in it when Ibought it, but they‘re different brands & I have no way of telling when either was purchased. Would my assumption be correct,and should I replace the battery with the higher voltage reading (or both)? What started this was when I bought the rv, beforedriving home I turned on the headlights and one went out immediately. I turned them off & the seller turned them back on &the second headlight went out. I left it for him to fix. He replaced both headlights. The first time I used them the new ones wentout together. I switched to high beam & after about 10 seconds they both went out. I knew something was wrong & suspectedthe regulator first.Mike SmithJanuary 12, 2013 a 4:48 pmReplyThey do make 16 volt batteries and alternators. They are commonly found in race cars. 16 volts is too high for a 12 volt system.You could be overcharging your batteries.TechJanuary 14, 2013 a 10:36 amReplyI found the article SUPER helpful, because the guys at the auto parts store we talked with did a few confusing things. One guycalled a battery looking like a 6-pack of soda cans a gel battery, where as the guy he called in for more info called it AGM,which it probably actually is. However, the guy who actually did know it was an AGM battery told us specifically that itwouldn‘t have any problems if it was completely discharged…which sounded quite attractive. We‘re still planning onpurchasing the AGM batteries, but if I hadn‘t found the web page and wised up on the great info and tips you folks provided,we might have blithely followed his information and totally killed our battery (sucksville!). Thanks for a great website!!!!!!!!Adda LamonJanuary 16, 2013 a 8:41 amReplySir I will be very thankful if you guide me to build a charger of a 4 volt Li ion battery(which I have dismantled from my oldlaptop battery)……Thank You.SilasJanuary 17, 2013 a 8:42 amReplyWe are unable to provide you the information you need. We are a reseller. We do not build or manufacture any chargers.TechJanuary 17, 2013 a 9:14 amReplyTHANK YOU!!!! The information on this page was GREAT!!! It is now my “Go-To” reference for batteries!!!!Ms. SafetyJanuary 18, 2013 a 12:05 pmReplyThanks for the compliment! :)TechJanuary 18, 2013 a 12:06 pmReplySir, I want to know a matter. When a 12V, 7.2AH rating battery is fully charged, is there any current flow to the battery wherethe charger is still plug in? and what is the actual voltage when the battery is fully charged? Please ans. to me.

Thanks in advance.Mizanur RahamanJanuary 25, 2013 a 11:17 amReplyWhether or not current is going into the battery after being fully charges is entirely dependant on the model charger you use andtherefore I cannot answer your question. Micro processor controlled chargers will ‘float’ a battery after full charge. This isusually ~13.4 volts with little to no current. However, if you want to know what resting voltage (off charger) on the batteryitself is considered full charge, please refer to this article for the answer.TechJanuary 25, 2013 a 1:06 pmReplyHi,my husbands 650cc motorcycle wasn‘t turning over so we figured it was the 12v battery. In order the check that it wasn‘tanything else we hooked up my new smaller scooter 12v battery to his bike and got it running. Now the scooter battery won‘teven turn the lights on the scooter even though the voltage meter says its fully charged. Could we have damaged the battery byusing it in a different machine? The bikes take different size batteries with different amps but both 12 volts.thanks.NickiFebruary 2, 2013 a 7:17 pmReplyThere should be no issue using a smaller 12 volt starting battery for the motorcycle. I‘m surprised if the bike was able to startwith a smaller battery. If the battery is truly fully charged, can you provide a resting voltage reading (bike off)?TechFebruary 4, 2013 a 1:18 pmReplySir, Thanks for the article. I Have a yacht with 4 Trojan T105‘s(6v – 2 in series- paralleled X 2) as one bank and a truck andtractor battery as the other bank. These are constantly charged by both solar panel and wind generator ( through a regulator)and also charged when the motor is running by alternator.My question;- Can I replace these wet cells with AGM batteries without changing any charging facilities? and if this is OK, do Ireplace them all with dual purpose AGM‘s or do I have 2 different banks, 1 starting , 1 deep cycle. I have a manual(idiot)switch, for selecting each battery bank or both. My motor is a Ford Lees 85 HP deisel. Thanks in advance.Reg RaynerFebruary 12, 2013 a 8:59 pmReplyMost AGM batteries require no special charging accommodations. I recommend using deep cycle and starting batteries for theirrespective purpose. That way, you‘re getting the best performance based on the demand.TechFebruary 13, 2013 a 8:49 amReplyI have a Yamaha golf cart I purchased 4 yrs ago. Last winter I parked the cart in my heated garage and did not recharge thebatteries during the 3 1/2 month period. By spring the batteries were so discharged thatmy cart charger would not work. I used acar battery charger to charge the 4 12V batteries separately. I limped through last summer having to charge to cart every 18holes. I haave recently read about de sulfating the batteris. I was thinking about trying this before I spring for new batteries.Can you recommend a product to do this and if I can use the cart charger when doing this or would I have to charge thebatteries individually. Thanks for the great article.Jerry AndersonFebruary 17, 2013 a 9:50 amReplyI recommend using the liquid additive called BATTERY EQUALIZER and also the PP48L ON-BOARD DESULFATOR byPulse Tech.TechFebruary 18, 2013 a 8:58 amReplyDo you recommend a 2 battery solution for a boat? 1 for starting and 1 for deep cycle? Or would a dual purpose battery besufficient? The engine is a 90 hp outboard.DonnyMarch 4, 2013 a 1:44 pmReplyWe recommend using a dual battery setup versus the dual purpose batteries. You get better performance for your needs thisway (starting the engine and running your electrical system).TechMarch 5, 2013 a 9:14 amReply

Great Article. If I have a 80 Amp Hour battery and use a winch that is drawing 435 Amps under load with a 90 Amp alternatoron the vehicle, how many minutes can I winch before I fully drain the battery or cause the vehicle to turn off? What formulaare you using?TimMarch 16, 2013 a 6:54 amReplyQuestion, i have access to some lead acid batteries with much more life left in them…..more than i need at any one time. I wantto put some in extremely long storage (5to10) yrs) Can i remove the electrolyte, flush then store? I read somewhere after flushto refill with ph neutral water and storing worked well. Another that after flushing used inert gas argon and sealed battery vents.Not concerned with losing a little capacity as these are very robust batterys. what would you recommend. I would charge thesefully then remove electrlolyte and store it properly until redeployment.SeanMarch 17, 2013 a 12:16 amReplyI have a 12v 100 amp hour wet cell battery at work. It was taken out in the fall and put on a smart charger. Now I was going toreinstall it back into our equipment. I noticed that the end with the negative post is swollen. With a load test it passes at 9.5v‘s.no other physical damage is found on the case. Could the one cell have pressured up and not vented?JohnMarch 19, 2013 a 9:50 amReplyIt could have had some gassing at some point without actually damaging the cell, as may be indicated by the continuedperformance.Jeremy FearMarch 19, 2013 a 3:45 pmReplyIs it possible for a AGM battery to test 100% on a load test and still be bad? My battery shows 12.8v unconnected. In themotorcycle it shows 12.6v and with the key on it drops to 12.1 and won‘t start the bike.DavidApril 12, 2013 a 4:36 pmReplyYes, it i s possible for it to have an internal ‘open’ in the cell. This happens when a weld point begins to come loose in thebattery and it is unable to pass any significant current along the now thin connecting point.Jeremy FearApril 15, 2013 a 8:01 amReplyI need a battery for a lighting setup for artfair booth (outdoors).I want to use 6 LED lights (14-watt Par30 bulb 3500K).also use of a fan for cooling the booth.which type of battery do you recommend.DonnaApril 30, 2013 a 5:55 amReplyI would recommend an AGM battery for this type of useage.Jeremy FearMay 6, 2013 a 7:48 amReplyI am battery deficient. I am charging a battery on trickle charge, I know that much, but how do I know what the red and blackbits on the charger mean? And how long til it charges? My hubby used to do all this but alas he is no longer here.Thanks for inputSandieMay 9, 2013 a 4:35 pmReplyI appologize, but I‘m not quite sure what you are reffering to by the ‘red and black bits’. If you want to send me a photographof the charger in question, my email is tech@batterystuff.com, then I will be more than happy to assist you from there.Jeremy FearMay 20, 2013 a 8:01 amReplyHi.I have 2 12 Volt batteries and want to use them both/ But i still want to use them for 12 volts. I just want extra backup.Please reply me anyone ASAP.PulkitJune 25, 2013 a 10:39 pmReply

Here is an article that explains the answer to your question. Should you have any further questions please feel free to email ourtech guys at tech@batterystuff.com.www.batterystuff.com/kb/aricles/battery-articles/battery-bank-tutorial.htmlRobin BrokawJune 26, 2013 a 9:04 amReplyBrilliant article. Has really explained the internal working of various makes of batteries, better than anything I have comeacross here in the U.K.JohnSeptember 1, 2013 a 3:04 pmReplyWhat a well written article. Thank you!My interest in the topic comes from wanting to maintain our trailer’s 12v AGM battery over the winter. We brought it home andput it in the basement workshop, but I discovered tonight that it was down to 10 volts.I’d like to put it in the cold room where there’s an unused plug but was worried about the “well ventilated area” instructions.The article says AGM batteries are the safest type, so would it be safe to charge it in the cold room? (10 × 4 × 7 feet, with topand bottom 4” pipe vents)LarryDecember 2, 2013 a 5:31 pmReplyThanks for a very informative article. I own an older Honda Goldwing with lots of electrical gizmos. I have replaced the batterytwice in last year. My dealer replaced the last under warranty about three months ago. The new battery worked fine when I wasdriving the bike frequently. But after letting the bike set for about two weeks I now have another dead battery. I hooked up mytrickle charger, it only has a light that tells me it is charging, I left in on for about a week it did not recharge. I then hooked upmy battery charger, it tells me it the battery is fully charged at 6 volts. Does this mean I have three bad cells? This is the secondtime this has happened, the first new battery lasted about six months this one about three. Do you think I got bad batteries. OneI think maybe, but two in a row.HaroldJanuary 19, 2014 a 6:03 amReplyWhat are the electrodes and the electrolyte of an AGM battery????Feterom AdolfoMarch 10, 2014 a 3:19 amReplyDuring periodic check when I observe that water level is low, I add distilled water to cells of lead acid battery. After a shorttime the fluid starts oozing out from the caps. It continues for about 12 -15 hours. What is the cause of this problem and how itcan be rectified?AtharMarch 17, 2014 a 5:15 amReplyBest written, most through article I have read regarding batteries, thank you!I have a BMW with AGM battery that was just replaced. I purchased a CTEK multi us 4.3 smart charger to lengthen the life ofthis new battery. I attempted to charge 3 days after installation, but became concerned as the charger was hot to the touch after2 hours and still in the bulk charging state. Should I be concerned by the heat? There was no indication of anything awry otherthan the charger itself being hot.Interestingly, the old battery never remained in the bulk charging state this long and I never experienced the charger ever beingwarm.Anders DMarch 18, 2014 a 9:02 amReplyI would not be concerned if it is hot after 2 hours, but if it has not entered into maintenance mode after 12 hours, I would checkthe battery to ensure it is good.JeremyMay 12, 2014 a 11:56 amReplyCan you use a AGM battery by laying it on it’s side or must it be in the upright position? If so, does it make any difference whatside it lies on (battery posts toward the top vs toward the bottom)Dave MApril 5, 2014 a 7:34 pmReplyDave, you can use an AGM in any position, except directly upside down.JeremyMay 12, 2014 a 12:21 pm

ReplySir Good day! i need with my newly bought gel battery, i dont know if i have to add sulfuric acid… i used it with my u.p.s. andit cant five any power to my computer when i unplug the power cable of the u.p.s.when i read the power rating 12.5V i dontknow the ampere since i dont have amp meter. but in the battery it says 7Ah/10H. i thought it is better than my old VRLA with12V 4.5Ah ratingMarieApril 5, 2014 a 8:50 pmReplySounds like you should talk to the manufacturer. If its gell, then you wouldn’t add any acid, and most cases if its AGM it wouldcome prefilled. The 7AH will last longer than the older 4.5AH one.JeremyMay 12, 2014 a 12:22 pmReplyWith a BS in Chemical Technology and eperience with batteries, I congratulate you for this article where expertise and generalpublic understanding are mixed in a state of the art level. Talking for shalow cycle batteries where Ah has no sense becauseCCA matters people has to be aware that this battery has to be fully charged, and if discharges only 20% i.e below 12.6 Vaffects the life of the car battery. The status of battery has to be checked every weak, while you check the cold inflationpressure of the tire. To have a optimal inflated tire, means an optimal tire foot print i.e an optimal tire grip. So at this time checkthe battery voltage in your car parked overnight, start engine check again and you’l get 13.5 to 14.5 i.e. this is the status ofalternator and voltage regulator in your car. If not using a vehicle use a battery tender that start charging at 12.6 V and stops at14.2 – 14.5 V. Not hapy with comercial battery tenders, I made my own using a NE555 timer as precission comparator an morecomponent. I can adjust ON at 12.6 – 12.7V and of at 14.2 to 14.5 volts according to the status (age ) of the battery. Increasingthe battery voltage above 13.2 V, starts equilizing process. The weak cealls continue to charge and the strong start boiling. I dothis proces at 250mA untill battery saturated, and after turns OFf to let battery to relax. I never buy a maintenance free battery,because I must check the electrolyte, level, top with H2O, and if necessary check the density.SamApril 29, 2014 a 5:58 amReplyI have n ABM 12volts, 120AH battery and a Wet Cell 12volts ,120AH battery can I connect both of them to my solar system inparallelFrank TuckerMay 2, 2014 a 11:36 pmReplyWe only recommend connecting batteries of same type, size, and age together in a system.JeremyMay 12, 2014 a 11:58 amReplyBut why are there no tech replies in 2014?Jim BiggerMay 12, 2014 a 2:49 amReplyJim,Technical questions can be submitted using the “contact us” tab at the top of the website. The comments for articles are notalways reviewed by Techs, so the best way to get an expedient answer to a question, is to contact the correct departmentdirectly. ThanksJeremyMay 12, 2014 a 12:00 pmReplyWe have a few 10 tonne dump trailers that are towed behind a few chev 2500 3/4 ton trucks (1 alternator)1 battery. Also towedby 2 ford 1 tons which have dual batteries in them.We are using deep cell wet batteries 175AH (D27’s) one battery in each trailer. The batteries in the trailers only get a 1/2-1 hourcharge from the 7 way trailer plug when they are ran to site and dumped. I don’t have the amp draw of the “Dyna-Pack)electric/hydraulic motor/pump unit yet. It takes 15-30 seconds to fully dump the trailer. The batteries don'tseem to last too long to these guys. The charge from the tow vehicle may be to low as the voltage dropin the 12 or 14 ga. wire used in the typical trailer tow package. I was thinking about wiring in #4ga. from the font to the rear trailer with a battery isolator so the trailer battery could receive abetter charge rate., specially if being dumped every hour or two and only getting 1/2 or little morecharge in between. Is it worth it $150 + isolator. I can install and get reasonable pricing on wire & terminals etc. Alsowhat is the best battery to use as the trucks have different batteries in each of them?? Good site for info I must add.RandyMay 21, 2014 a 9:58 amReplyRandy, using an isolator will get better results. Thanks

TechMay 21, 2014 a 12:37 pmReplyI had solar system, Know I want to add new set of batteries with old one for charging purpose, both pared as 24V sets. 24V oldset and 24v new set. is this work or any problem, i will face during charging for solar panels.or should i charge separtly and use dual purpose. Once charge new and than Old.In house for electric city,Should i combine both sets, or I use old to discharge than switch to new for use.ZareefJune 14, 2014 a 11:37 amReplyI would recommend charging separately. Mixing old and new batteries is asking for trouble.TechJune 16, 2014 a 11:04 amReplyI have installed a few advanced GPS devices on a fleet of vehicles. The manufactures paperwork says they should be wired intoan output capable of at least 13 volts. I have not had any problems with the devices on vehicles with a normal 12 volt carbattery and wonder if there would be any possible problems if I wanted to install them on a recreational vehicle like a PolarisATV/Quad or a Side X Side with a 12 volt battery?TracyJune 26, 2014 a 12:50 pmReplyIt should work fine, but always check with the manufacturer for a hard answer.TechJune 27, 2014 a 8:48 amReplyI have a few questions on battery reconditioning, based on reading of various How To and DIY sites, and hope that you are ableto help: 1 – The powder that everyone seems to suggest is Epsom salts, is that correct? 2 – Is there a specific type of theseEpsom salts that is appropriate? 3- What are the mixing specs for the solution? Thanks a lot! We would require more information about your situation. Please contact one of our techs at tech@batterystuff.com.ArieSJuly 8, 2014 a 2:50 pmReplyI have a boat with a normal marine 12v lead acid battery I would also like to add a second battery to provide for lets say a 12vaccess port for accessories. Unfortunately I have limited space for a second full sized battery. Could I use a smaller lets sayATV type twelve volt battery connected through a dual battery charger relay isolator so that both would charge when the motoris running but both would not drain when the motor is not running.We would require more information about your situation. Please contact one of our techs at tech@batterystuff.com.GarthJJuly 15, 2014 a 9:58 amReplyI have two 12v 100AH battery it is connected with IPS recently I see the battery is very HOT & IPS Full Charge indicator notshowing full charge. I check Battery Water Level ok. Then I disconnect all battery from IPS 2 days take time to cool the battery& after battery fully cold I connect it to IPS but again the battery is very HOT. What is just happening Can you tell me please.My battery Name Lucas AP 100 12V 100AH 21 Plate made by Rahimafrooz Bangladesh. Please give me the repply. ThanksSaiful Haque KhanBangladeshsaiful6848@gmail.com+8801716579824We would require more information about your situation. Please contact one of our techs at tech@batterystuff.comMd. Saiful Haque KhanJuly 18, 2014 a 1:06 pmReplyWe have a John Deer Gator (riding toy)for our Granddaughter. The connection for the battery has corroded down inside. Isthere a safe way to clean it out? It is a very tight area.Laura HargisJuly 23, 2014 a 12:35 pmReplyBaking soda and water, but not in the battery!, just for the terminals and connections.AdminAugust 15, 2014 a 2:14 pmReplyThank you for some great info. We have a travel trailer that we have parked at a camp area on the back the farm. It hasn’t

moved since we bought it 5 years ago. We charge the battery with a Honda 3000 generator. After many years of frustrationusing a flood cell deep cycle battery we just installed a AGM battery. (I believe we brought the charge down on the batteriestoo far, too often). Anyway we just bought the AGM battery because we understand it will charge much quicker than a floodcell. My question is using this type generator on a trailer, will that work for a AGM or should we do anything different forcharging?Thanks again.T-ManAugust 16, 2014 a 11:39 amReplyIf AGM batteries aren’t damaged by a car’s alternator charger why do they need a special charger?MauriceAugust 23, 2014 a 6:45 pmReplyThey really only need a specific charger if they are being maintained long term with a constant charger. The exception isspecialty AGMs such as Odyssey batteries or aircraft batteries.TechAugust 25, 2014 a 2:36 pmReplyHi, I bought a sailboat with 2 batteries and a selector which reads off/1/both/2My question is about what you say about batteries being the same size, rating and type. Of the 2 that came with the boat, #1 is areg. acid starting battery and #2 is a deep cycle used as a house battery. Is that bad? should I avoid the “both” position of theselector?JoelSeptember 4, 2014 a 10:31 amReplyGood Question! The selector switch is designed to get the boat out of a bad situation, say for instance you were unable to startthe boat. This enables you to bank the other battery together in such situation to get the boat going again. You do want to avoidtying them toghether unless your are in a problematic situation.TechSeptember 12, 2014 a 12:37 pmReplyGreat article, easy to understand and informative. I have a few questions about my RV battery cables. I was about to replacethe 2 12v marine batteries on my RV with 2 6v deep cycles, when I realized the cable situation seems strange and possiblyscary.- The ends of the cables, for about a foot before the terminal connectors, are all taped up and homemade. Should I beconcerned about that? – How do I know if they’re an appropriate size for the battery size? – There is a thin black ground wirecoming from the taped up part of the + cable, which is bolted to the trailer frame. Why would the + cable be grounded? Isn’tthat what the – cable is for?!The 2 cables that were used to connect the 12v batteries in parallel are also of this taped-up homemade variety. I was going touse one of them to connect the 6v in series, but now am unsure whether I should use ANY of these cables at all. Wiring in newcables seems really daunting because I can’t see an obvious way to access where they run up into the bottom of the trailer. ButI don’t want to be unsafe, so…Thanks in advance :)KylaSeptember 5, 2014 a 3:17 pmReplyI would talk to your local RV Service Center if you feel the homemade cables are questionable. If you plan on rewiring the theconnections to replace the existing cables we recommend staying with the same gauge wire that originally came with your RV.Obviously the last foot or so you said is homemade, so you would want to look further up to see what size the original cable is.If your changing charger, converter, or inverter (or an all in one) then we recommend you look to that manufacturer forrecommendation.TECHSeptember 25, 2014 a 9:48 amReplyA BMW 128i w/AGM BATTERY—-CAN IT BE REPLACED W A QUALITY WET CELL BATTERY?THANKS—WILLIESeptember 16, 2014 a 2:22 pmReplyIf your existing battery is a WET cell then you can use an AGM. However if your original battery was a GEL then you wouldhave to contact BMW to verify that your charging system will charge and AGM as they charge at a higher rate.TECHSeptember 25, 2014 a 11:11 am

ReplyWow…thankyou for existing. We are beginning to get a solar set up organised for free camping and I have a plethora ofquestions that hopefully you can answer for me. We intend to run a 12v52 litre fridge and strips of led lights. What do I need toknow about these applicances when planning the battery set up. We are looking at a 12v 260 AH AGM battery using a 140Wsolar panel to charge. Would one battery be enough or should we look at two – the fridge needs to run most of the time but theled lights would be just at night. If we did get two what is the difference between wiring in series and in parallel ….is one waybetter than the other?? And I need reminding … In paralel is it positive to posiive and neg to neg.. Thank you so much for yourtime and expertise……cheers Suz from OzSuzSeptember 20, 2014 a 4:12 amReplySuz I would suggest reading our article: Solar Systems the Right Way. This will help you gather the proper information todetermine if your panel and battery setup would be sufficient. As far a series vs parallel I suggest looking at our article: BatteryBank Tutorial – Series and Parallel. This article will show you possibilities of creating different type of battery banks, andmaybe the possibility of going to two 6 volts batteries for less than two 12 volts batteries would be for the same Amp/Hrcapacity.TECHSeptember 26, 2014 a 12:44 pmReplyFantastic article though I admit even the laymans terms seems to go over my head. I live in the UK and have a QUICKIE JiveMidwheel drive wheelchair made by Sunrise Medical which uses 2 × 12volt 70 amp sonneschein GEL Batteries I Have a 8ampGel battery charger but in the 27 months I have owned the chair I’ve had to have 4 sets of replacement batteries as they failafter 6 months apparently ( according to the manufacturer) because of a faulty Cell. I have followed the manufacturersguidelines with charging the battery, which states as soon as you’ve finished using the chair put it on charge. . Though I oftenwait about 5 hours to put the chair on charge. I do this and then leave it. So the chair gets between 13 & 18 hours charge even ifI have done only 5 miles, which is my about my average daily use. Should I put the chair on charge straight away the leave italone even If I need it? I have my manual wheelchair to get about in inside my house. Any help to prolong the battery life isgreatly appreciated. I have repeatedly asked both Sunrise medical & sonneschein for help over the past 2 years with n how toalleviate this problem but have had no reply.Mike CoshanNovember 19, 2014 a 2:16 amReplyI would definitely not leave the batteries sitting in a discharged state, plus it is never recommended to discharge a battery morethan 50% so if your 5 mile run does this then that could be affecting the batteries life. If you are not running them below 50%then I would look to the charger, and be sure it is at least a 3 stage charger, anything less is not recommended for those sizebatteries. Feel free to contact our Tech Department for assistance.TechNovember 19, 2014 a 2:56 pmReplyHi, I have been getting a headache with all the conflicting advice on my current and planned dual battery setup. I have a 105Landcruiser with 4.2 diesel and standard 110 amp alternator. I have a dual battery system with a Delkor 27HR-70 Calcium anda brand new Optima Blue Top D27M AGM (replaced the other Delkor which died) as the secondary battery for running utilities(fridge etc). They are parallel connected through a RedArc 100 amp isolator. I also have a RedArc 120W portable solar setup toassist with powering for extended camping etc.Firstly, is this current setup likely to damage Optima through lack of charging output. And if so would an in car BC/DC chargerresolve the issue.Secondly, as I am not sure of the age / condition of the Delkor I am thinking of replacing it with a new Optima Yellow TopD27F. Would this make my current setup sufficient? Or is the standard 110 amp alternator still not up to fully charging theAGM’s?Would really appreciate some feedback and guidanceCheers We would require more information about your situation. Please contact one of our techs at tech@batterystuff.com.DarrenOctober 3, 2014 a 7:56 pmReplyThank you so much for writing this. I am certainly going to give to my husband to read and for reference. I just purchased ayamaha 36v golf cart that needs new batteries. There are 6 each, 6 volts batteries, which would you suggest?thank you !StellaOctober 14, 2014 a 8:09 amReplyWe carry some of the best Golf Cart batteries available. Any of the batteries listed in our Golf Cart Section would be

recommended.TechNovember 18, 2014 a 10:39 amReplyThe rating reflects how many amps you can pull from that battery over a specific period of time. In general the ratings goesdown the quicker you pull a load out of a battery, so a 200AH 10 Hr rated battery will have a higher capacity than a 200AH 20Hr rated battery.TechNovember 18, 2014 a 11:30 amReplyplease, am a little confused. whats the difference between a 200ah 20hr rated battery and a 200ah 10hr rated battery. am tryingto buy a deep cycle battery and i see 10hr on one and 20hr on the other. which one is better?EarthrealmOctober 16, 2014 a 2:46 amReplyGreat article. However, it seems that no matter how many articles I read on batteries, I can’t seem to grasp a full understandingof how it all works. And I say that because 6 years ago I purchased a highly modified EZ-GO golf cart that I use to get aroundthe woods of southwestern Pa. year round. Our temps run in the high 80’s in the summer to the mid teens in the winter, and attimes lower. I have a 48-volt system using 8 six volt T-105’s and a smart charger for the cart, and for my headlights and winch aseparate vehicle 12-volt battery. Now, I’ve read that I should not discharge my flooded T-105’s below 50%, but in all honesty,that is at times impossible to do. The woods are not that short in places, and at times…well mud is mud and you can’t predict it.However, I always check my water levels…they seem to remain a constant…and I always clean my terminals monthly, even ifthey don’t seem to need it. Your suggestions of using grease is great and I will do that on my next cleaning session. Now, I haveinstalled a new Warn winch and I winch my cart on and off my truck. I currently have one 12-V auto battery in the cart, but Iam concerned that I may be “out there” and the 12-V simply run out of charge. So, what I have been thinking of is replacing theone 12-V with two 12-volts and wiring them to still have a 12-volt output, but have a longer output “time” if you understandwhat I’m saying. I have enough room under the cart seat for the average width of a car battery, and about 24” in length. Whattype of batteries would you suggest would work the best in my situation?DaveTOctober 18, 2014 a 10:18 amReplyDave I would recommend our Calculator | Sizing a 12 Volt Battery to a Load to really determine your need. If you have furtherquestions I would suggest contacting our Tech Department.TechNovember 18, 2014 a 11:53 amReplyIm a designer/installer and have read literally hundreds of guides and tutorials over the years and none are a patch on this – hatsoff, you’re brilliant – and crazy helpful to have provided answers to every question posted here individually, for free, despiteyou having already answered 99% of them in your other excellent articles!People, don’t be lazy, sure this guy has a life so read ALL the FREE guides provided for you here before asking. Big respectsDeanNovember 20, 2014 a 11:09 amReplyI am in the process of upgrading my solar electricity in my house and need information regarding what electrical appliances 8AGM batteries will be able to power. I already have a solar panel array in place that is powering a solar water pump veryeffectively. I suppose I need to tell you the amount of watts the panel produces but do not have that info. at this time. Is it likelythat I can replace my propane frig. with an electric refrigerator, run power tools without the generator on, etc.?Thank you!SandraKanziNovember 8, 2014 a 9:00 amReplyAs solar is basically a math problem I would suggest reading our article Solar Systems The Right Way as a start, or Contact OurTECH Department for further assistance. Please be aware that we are not home solar experts, and it might be best to contact alocal home solar expert.TechNovember 19, 2014 a 11:58 amReplyLeave a CommentName Email (will not be published)Article Rating 1 2 3 4 5

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