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Solar Panel Inverters

Learn more about what Solar Panel Inverters do

What are solar panel inverters? What are they good for?

Solar Panel inverters are used primarily to change direct current to alternating current via

an electrical switching process. You can think of inverters used with solar panels as

electronically synthesized alternators.

Types of Solar Panel Inverters

There are three types of solar panel inverters:

Stand-Alone Solar Panel Inverters Synchronous Solar Panel Inverters

Multi-function Solar Panel Inverters

Stand-Alone Solar Panel Inverters

Stand Alone solar panel inverters function to change direct current (DC) from a battery toAlternating Current (AC). Stand alone inverters, which range from around 100 watts to as

much as 8000 watts, are used to power a vast variety of personal or small business

projects. Lower watt stand-alone inverters are often used to power laptop computers,whereas high-watt stand-alone inverters could be used to help power an entire household.

In order to calculate what class of inverter you need for use with your solar panel, youwill first have to determine the maximum sum of all of the Alternating Current loads inyour project (or home).

How to calculate the wattage you need from your stand-alone solar panel inverter

AC_LoadDryer+AC_LoadLaptop+AC_LoadIron

=Total AC Load

This is the wattage you need from your stand alone solar panel inverter.

You can usually find the wattage rating on your home appliances by checking the power

cable. The sum of these wattage ratings is what you need to determine the wattage you

need from your solar panel stand-alone inverter.

Surge-Compliant Stand-Alone Inverters

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It is important to purchase a quality stand-alone inverter that has a built-in ability to surge

if you are using heavy equipment, power tools, or automatic washers, dryers, and

dishwashers. These appliances and equipment require a surge on startup, which yourstand-alone inverter must be able to supply if you are planning to use these appliances.

Synchronous Solar Panel Inverters

The term Synchronous Solar Panel Inverters arises from the synchronous dynamic that

such a system creates between the utility company and a personal solar-panel installation.

Synchronous Solar Panel Inverters allow power generated by your solar panels to bestored in battery. If there is an excess (meaning you did not use as much power as you

produced), the power is sold back to the utility company at the same rate at which you are

charged!

On the other hand, if your solar panels are unable to provide you with the power youneed, your Synchronous Solar Panel Inverter will allow the utility company to supply

power to make up the difference. The advantages of a Synchronous Solar Panel Inverterare many, as you can see. This Synchronous Solar Panel Inverter system is quite useful -your batteries will provide you with energy during the utility company's power outages,

and on bleak, rainy days, you won't have to worry about your solar panels performance,

because any power you need will be supplied by the utility company via your

Synchronous Solar Panel Inverter.

A final advantage of Synchronous Solar Panel Inverters is that you will not have to

precisely calculate your Alternating Current load in order to set up the system. It is only

necessary if you want to have complete reliance on solar panel in most scenarios, but ifyou are comfortable with buying a steady but small portion of power from the utility

company, a rough estimation of wattage from your solar panel system should suffice withthe Synchronous Inverter.

Multifunction Solar Panel Inverters

Multifunction Solar Panel Inverters combine the best of both worlds, and they are usually

the best choice for your solar panel system. While more expensive, multifunction

inverters may be your best choice. Contact your solar panel dealer for more specificinformation on Multifunction Solar Panel Inverters.

True and Modified Sine Wave Inverters

An inverter converts a direct current to an alternating current through a delicate electricalswitching process. This process makes an inverter function as a synthesized alternator,

which are typically used to produce AC current by creating a smooth alternation, similar

to a pendulum gently swinging. This alternation takes the form of a sine wave, which is

the ideal wave pattern for transmitting AC power.

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Modified Sine Wave Inverters

Modified Sine Wave inverters are better in typical solar applications when electric motors

are not involved. They are not quite as efficient as true sine wave inverters, but you'll find

that they are much more affordable. Unlike true sine wave inverters, modified sine wave

intverters produce a stepped waveform, which isn't really a sine wave at all.

Because the current is not alternating perfectly, the stepped waveform of the modified

sine wave inverter causes the inverter to generate an irritating buzz. Take this into careful

consideration when purchasing an inverter.

True Sine Wave Inverters

True sine wave inverters are very efficient and have a very accurate waveform to the true

sine wave. True sine wave inverters are a little more pricey than modified sine waveinverters because of the reduced noise and their strong compatibility with certain devices,

such as electric motors. This is the better option if you value silence, or want optimalperformance from electric motors, such as those found in an electric water pump.

Solar power and voltage inverters

One of the things I love about solar poweris not only the clean, green renewable energy

aspect and gaining independence from the grid, but also their relative simplicity in termsof the number of components needed to create electricity.

All you need is a solar panel, some wiring, asolar regulator(aka charge controller) and a

deep cycle batteryfor storage in some cases - and an inverter, which is a critical

component in turning power from the panel into juice you can use in the home.

What is an inverter?

The output from a solar panel is usually 12 or 24 volts direct current (DC). While there's

many appliances on the market that can run on 12 volts (mainly camping and off roadgadgets), the "normal" appliances in our homes need a different type of juice - 110 or 240

volt alternating current (AC) depending on the country you live in. The magic box that

can achieve this conversion is the inverter.

AC? DC? What's the difference?

My understanding is essentially it's in the movement of electrons. A flow of direct current(DC) electricity is continuous in one direction, the current in AC electricity alternates in

direction.

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Past that explanation, you'll need to consult someone more familiar with electricity than

me, but AC is used for mains supply primarily because the voltage can be transformed

and carried over a longer distance with less energy loss.

The odd thing is that many AC appliances actually run on DC. While they plug into an

AC outlet the internal circuitry converts this into DC.

I'll leave it at that before I confuse myself (and you). The bottom line is, you need an

inverter to run appliances designed to work with mains electricity :).

A note on cheap inverters

I bought a cheap inverter for my trips into the outback. It's only rated at 150 watts, but

that's enough to power a notebook and lights running off 240 volt (mains supply current

in Australia).

However, the inverter gets quite warm, even when running a 5 watt fluorescent and thatheat represents energy loss and wasted deep cycle battery draw. Plugging in my notebook

really makes it heat up and in summer it will often trip out the inverter.

I discovered that this is common when running appliances that have adaptors off cheap

inverters. Mine is ok in a pinch, but for serious off grid work such as powering a housewhere you'll be using more than a couple of hundred watts at any given time, don't skimp

on an inverter as it will cost you more in the long run; go for a true sine wave inverter.

Bear in mind too that if you're buying a full solar power system, renewable energy

rebates offered by many governments can substantially reduce the cost.

True sine wave

Sounds like surfing jargon doesn't it? A true sine wave inverter is the best choice if you'repowering sensitive electronic equipment or reliant on a steady flow of "clean" electricity.

True-sine wave inverters crank out electricity that is identical in quality (and sometimes

better) than the power you draw from a mains supply.

The other type of inverter, and it's the type I have, is a modified-sine wave. Unlike truesine wave, which appears as a smooth set of waves when viewed with an oscilloscope, a

modified sine wave appears as being choppy and squared - and that represents the qualityof the power. It's the poor cousin of true sine wave.

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Mains grid vs. SAPs inverters

When selecting a true sine wave inverter, you also need to ensure you buy the right one

and depending on the type, you may need an appropriately accredited installer to do thework.

A mains grid inverter is one where you'll not only be drawing power from the panels, but

any excess juice being produced at a particular point in time is fed back into the grid - i.e

amains grid connect solar power system. You'll definitely need a licensed installer toperform the work given the voltages involved.

A SAPS inverter is one for a Stand Alone Power System - i.e. an off grid system. These

basically just plug into yourdeep cycle batterybank, so you can install them yourself;

just take heed of the instructions to prevent any nasty, ahem, shocks.

What size inverter?

The size of the inverter you'll need depends upon your peak power loads. If you add up

the wattage of all the appliances you'd be using at the same time, that will give you an

indicator. You can also use thissolar power system builder- based on your input, it will

tell you the size inverter, panels, batteries etc. you'll require based on your needs.

Important note - electrical appliances often use far more juice when they are firing up

than in normal operation; up to 3x as much. For example, a 200 watt rated appliance

might use up to 600 watts for a few seconds when it is switched on; so you'll need toensure the inverter you buy can handle high draws briefly.

If you're buying an inverter for anything else apart from light use, it's really best to talk toan expert in renewable energy first - guessing what you'll need can wind up being very

costly exercise.

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