EV SafetyDavid Kerzel

Modular EV Power LLC

Pompano Beach, Florida

EV Safety

Type Mass Produced Conversions

EV Safety

Type Mass Produced Conversions

Location Home Work Public

EV Safety

Type Mass Produced Conversions

Location Home Work Public

Who Owner Public First Responders

EV Safety

Type Mass Produced Conversions

Location Home Work Public

Who Owner Public First Responders

Concern Electricity Fire Accidents Other

EV Safety

We are early adopters of this technology

We need to use the technology safely

We need to encourage others to use the technology safely

We need to understand the Risks

We need to be able to explain the facts to others

Change

Much of the worry about EV’s relates to ChangeMany people don't want any changeOthers accept it as they see the benefitsSome may have business to looseSome just enjoy being negativeSimple factual responses and answers are best.

First RespondersFirst responders worry about there safety

In ICE vehicles they cut the battery cable

In Ice vehicles there is no high voltage

In Ice vehicles it is easy to tell if the engine is on

Training and experience is what is needed.

When Air bags were first used there was unfounded concern

about them exploding in a fire.

Electricity

Electricity is dangerous and needs respect.

We have electricity in our homes and we are safe.

It is safe because:

• There are codes and guide lines for construction

• Products are tested and listed UL or ETC for safe operation

• Building inspectors verify parts are used as intended.

ElectricityThe EV stores it electricity in a battery pack.

The voltage is typically 120 volts DC to 400 Volts DC.

The battery can store 10 to 40 KW-Hours of energy.

That is a lot of energy. My home uses 5 KW-Hours of energy per day.

My home could use 38 KW-Hours of energy per hour but it does not.

One gallon of gasoline contains about 33 KW-Hours of energy.

People feel safe with gasoline because it has been around for so long.

There are gasoline car fires.

Electricity in the CarEV’s are electrically isolated form from the chassis and it is grounded

Electricity must flow through a body.The isolation prevents this.

Battery in Production EV’sMan years of engineering, testing and Design

Designed to be safe, long LifeIn a Package• Touch Safe• Containment• Crash worthy• Serviceable• Battery Management Control

Disconnecting means for service and first responders

Standardized wire colors to identify high voltage

Battery in Production EV’s

Designed to be safe, long LifeIn a Package• Touch Safe• Containment• Crash worthy• Serviceable• Battery Management Control

Batteries in ConversionsGoal is often get as many batteries in as possible

Initial goals are often to be safe and long Life

serviceable Is it really touch safe?

Will the batteries and any

fluids be contained?

Is it crash worthy?

Will it be serviceable?

Batteries in Conversions

What is crash worthy?The Converter’s Guide to the Galaxy and EV ConversionsBy Richard W. Marks, A complete book about how to plan a safe conversion www.goldcoasteaa.org Battery mounting needs to withstand forces 20 times the battery weight in the forward and side to side directions.Things will bend and plastic covers will move. Plan for shorts or damaged wiring.Batteries should never be in the cabin with the occupantsEven though they may appear low cost Lead Acid and AGM have so much mass and spill potential they should not be used today.

Batteries in Conversions

Batteries in Conversions

Fuses and circuit breakersRated at circuit voltage or moreT ratingsDisconnects, normal and EmergencyMore than one?Andersen ConnectorsOrange Wires for all high voltage

Batteries and FIRE

Any time there is lots of energy available fire is a possibility.• Wiring failures• Circuit failure• Water or fluid failures• Crash damageOne leads to another

Batteries and FIRE

The Volt Fires.Weeks after a Crash test the car burnsThe crash test caused the battery coolant to leak in the battery pack and got the electronics wet and the pack failed and burned.Coolant or liquids are not a problem with the 12V battery in present cars due to low voltage and chemistry.It is new technology and it would be great if every problem could be anticipated but it is the real world.

Batteries and FIRE

Conversion Fires.Yes, there have been many conversion firesNeal Young’s LinkVolt project car.In the movie “Revenge of the Electric Car” Gadgets fire looks to focused at the battery pack.Most seem to happen in the night with unattended charging.

Batteries and FIRE

Conversion Fires.Unattended charging and BMS often seem involved.These systems must have redundant safe guards to prevent over charging.They must take temperature into consideration and stop if a problem is detected. They must fail in the off state.My personal issue is poor quality BMS wiring. Telephone low voltage solid wire that can break or chafe leading to a serious problem with no warning. Ever notice automotive wires thick insulation?

Batteries and FIRE

Why so much on Fires.Lithium ion batteries are safe at the rated current levels and at the rated temperatures.They do have organic solvents inside that are flammable at higher temperatures.The real problem is over charging.The Li+ suddenly changes from ions to metal when over charged.The metal can short out a cell and cause a hot spot. The pressure goes up and the battery vents or bursts.One hot cell heats the next.Li metal is very active and can separate water to H² and OH, generate heat and burn.Water may not put the fire out.

Batteries and FIRE

What can we do to reduce the risk.Like production cars only use 70 or 80% of the pack capacity. This leaves a safety gap at the ends of the charge cycle. It also extends the number of cycles the batteries will provide.Recognize this as a serious problem and use the best construction and wiring around the battery pack.I would want a smoke detector in the garage even if I trusted the car!

J1772

SAE J1772:2010™ charging brings several levels of safety to charging and the electrical interface.There are extra costs with this extra safetyThere is also the advantage of a common compatible connector for most cars.

Level 1• Typically implemented as 12 Amps @ 120 VAC• 1440Watt-Hour• At 200 Watts/mile so 1 hour of charge hour gives 6

milesLevel 2• Typically implemented as 23 Amps @ 240 VAC• 5500 Watt-Hour• At 200 Watts/mile so 1hour of charge hour gives 27

miles• At 80 amps 1 hour of charge hour is 19,200 Watts

giving 96 miles

Why are EVSE so expensive

• Safety• Out in the weather• Vandals• Abuse like driven on• Liability• It’s new!

The CarCharger is in the car for level 1 and 2All electrically isolated form from the chassis and it is grounded

J1772 Vehicle Inlet

J1772 Vehicle Inlet Shrouded pin and sleeve design

SeparatedTouch safeProtected from damage

Starting to mateInterlocking protectionGround first

Fully matedFull contactLong Interlocking path

EVSEThe EVSE does not power the cable or connector

until it is latched and the car requests power

J1772 Pilot Signal

EVSE is UL listed and covered by NEC Article 625

Pilot Details• When disconnected the Pilot is +12VDC• Connecting Adds the diode and R2 which reduce the +12VDVC

to +9VDC• This starts the PWM signal, 1KHz, Positive PWM width

represents current • I = duty cycle X 0.6 6-51 Amps, then changes.• Close S2, +9/-12V changes to +6/-12 and contactor coil gets

power and car gets power.

Proximity• Tells the car it is connected.• It is OK to charge• Inhibit motion

Level 3 Fast DC

Direct connection to the batteryV2G possibilities

Level 3 Fast DC

CHAdeMo is the most established

Tokyo Electric Power Company, Nissan, Mitsubishi and Fuji Heavy Industries 500 VDC at 125 Amps

Level 3 Fast DC

• SAE J1772 Level 3

GM, Chrysler, Ford, Toyota, Honda, Nissan, and Tesla.Expected to be 600VDC at 200 Amps

Combines the J1772 Level 1 & 2 connector with the Level 3

EMI and RFI

Electric things do produce EMI and RFISome people worry about it other don’tThere are standards modern productsVehicles must comply to be safeDesigns limit the emissions no to interfere with others or radio.Shielded wiresConversions emissions are likely higher.

Mechanical Issues

• Always use the hand brake• Consider chocks• Vehicle Weight• Brakes• Weight balance• To much power

Electrical Issues

• Respect the battery pack• Disconnect the pack before work• Never work on electrical parts while

charging• Insulate tools• Long sleeves and gloves make it safer.• Never work alone

Charging Stations, EVSE

Public or business locationsLook it over for damage its outsideCheck the statusTry to advise someone if it’s downPlug inCheck that its functioningUnplug and move the car when doneWhat about that ICE car?What about unmarked 120V outlets

Charging Stations, EVSE

Place the cable to safe and obvious

Put the cable back

Concern and liability about people tripping on a cable in use or improperly stored

Charging Stations, EVSE

Use them when you can to show people they are needed.

EV SafetyDavid Kerzel

Modular EV Power LLC

http://modularevpower.com/ David@modularevpower.com

http://www.goldcoasteaa.org/