this post was submitted on 06 Dec 2023
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I thought that the media was a little over the top with reporting every electric car fire.

Little did I realise just how blown out of proportion it was:

"...electric vehicle battery fires are rare. Indeed, the available data indicate the fire risk is between 20 and 80 times greater for petrol and diesel vehicles. "

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[–] [email protected] 11 points 11 months ago* (last edited 11 months ago) (1 children)

But what is true is that electric vehicle fires are much worse to put out.

I love electric vehicles and miss mine (not lost to a fire, thankfully), but just want to put that out there.

This reminds me of the hover board fires. The fires were due to cheaply made batteries and the solution was to buy ones with batteries made by a reputable manufacturer like Samsung that didn’t typically cheap on its process like the knock offs did.

[–] [email protected] 6 points 11 months ago (1 children)

Worse?

Lithium just sits there and burns.
It gets hot.
It's hard to put out.
It re-ignites.

Unlike petrol, it doesn't explode under certain conditions.
Unlike petrol, it doesn't run off down the street and set other things on fire!

[–] [email protected] 5 points 11 months ago

Agreed, and most Car-b-ques are total, by the time the Fire Department gets there it's burned down to the frame.

[–] [email protected] 4 points 11 months ago (1 children)

The only thing to consider is that EVs have the possibility to catch fire when they are "passively" sitting unattended in your garage under charge, whereas liquid fuelled vehicles are more likely to catch fire in active use when everything is hot and things are being pumped around and someone is at the controls that can notice what's going on and take immediate action.

So a petrol car can sit in the garage with the ignition off and very little is happening electrically (or chemically).

An electric car will be sitting in someone's garage getting 5+ kW pumped into it for 3 to 10 hours overnight, every night. That's a lot of energy getting manipulated via charging circuits and going into a large box of reactive chemistry in the car.

Now all that needs to happen is that quality components are used and electrical standards are followed and some practical things like interconnected smoke alarms are used. In Australia that's mostly par for the course so it's not a huge concern.

But the risk of a house fire in the wee small hours is definitely increased. Doing a quick thought experiment, you can pull a tiny chance out of thin air, like "an EV (or it's charging system in the home) will catch fire while charging overnight once every hundred million times" and say, "imagine if there are a million electric cars in Australia", and the net result is someone's house burning down every three months. The media will be all over that shit if that happens, so car manufacturers and standards bodies have to really work at making that risk almost unimaginably tiny.

[–] [email protected] 5 points 11 months ago* (last edited 11 months ago) (1 children)

You know that petrol cars have electrical systems and batteries too, right?

Electrical issues are one of the bigger causes of petrol vehicle fires, and they don't need the engine to be running. Those vehicles also have a large amount of dangerous chemistry inside them, but that's somehow not a problem.

[–] [email protected] 5 points 11 months ago (2 children)

I'm an auto electrician by trade and I have been for 30 years. I do happen to know quite a bit about wiring on motor vehicles.

The difference I was highlighting is that a petrol/diesel vehicle parked with the ignition off is basically passive. It's very rare for a switched off fossil fuelled car to catch fire by itself after a few minutes have passed since you've turned it off. Fuel is shut off, nearly all circuits are off, anything still actively powered at that point draws milliamps and will be protected by fusing in the 5-10 amp range , and any spontaneous electrical faults (from eg rats gnawing wiring) will be contained as a result. Critical high current wiring for your starter is routed away from points where it can short out if disturbed by said rats, your alternator wiring is protected by fusible links, and finally, your 12 volt battery has a quite limited capacity (in the 0.5-1kWhr range, if we want to compare it to an EV).

And then you have an electric vehicle which when "off" in your garage will have at least several kilowatts of power flowing through it from a high capacity mains circuit and a wall charger full of electronics. This goes on for many hours to charge a 50 to 80 kWh battery in your car while it is completely unattended and you're asleep. A battery that is designed to put out a hundred-plus kilowatts when you stomp on the go pedal , and so is fused appropriately for that kind of current.

Of course it will also have protections, but the fact of the matter is that it's a fundamental change in the operation of your vehicle. Now instead of being "turned off" overnight, a lot of high power things are occurring. The risk of a failure is higher simply because things are actively happening. Your car is active while you're driving it just like a petrol car is, but now it's also very active while it's parked overnight.

[–] [email protected] 1 points 11 months ago

Think of all the times in your last 30 years that you have seen an amateur Auto Elec (either a qualified mechanic, panelbeater or backyarder) that has royally screwed the electrical system.

Now think about all the times you have had a Car or Caravan that was worked on by one of your competitors.

There has to be public awareness that only EV-qualified auto electricians should be even thinking about touching an EV, especially after what happened at Thrifty Car Rental at Sydney Airport.

[–] [email protected] 0 points 11 months ago (1 children)

The 12V battery has a low capacity, but it has a very high power output - it has to, to be able to turn an engine over. It's also quite close to a lot of flammable fluids.

You're putting 5kW into an EV, but that's a system designed for 150+kW of power. They don't even get warm.

[–] [email protected] 5 points 11 months ago (1 children)

Tell me something I don't know. How about you have a good look at my post again, read the very first line, and then rebut some of my actual points.

Simply put:

There are more points of failure and associated risks in an active high power charging circuit in an unattended EV parked overnight versus a fossil fuelled car in the same situation. Those failures are managed by good engineering and QA during assembly and install. Do we have good engineering and QA right now in our nascent EV market in Australia? We should but we won't really know until the size of the EV fleet in Aus gets large enough to bring any issues to light.

The risks are miniscule, but to claim that an EV on charge presents less risk than a similar fossil fuelled vehicle parked overnight is laughable.

[–] [email protected] 2 points 11 months ago* (last edited 11 months ago) (1 children)

Bring on solid state batteries!

"Solid-state batteries address the safety concerns of traditional lithium-ion batteries by replacing the flammable liquid electrolyte with a solid counterpart, virtually eliminating the risk of fires and explosions.

Solid-state batteries have superior characteristics compared to lithium-ion batteries, such as higher energy density, longer lifespan, and faster charging. They also do not require additional safety features, making them lighter and more efficient for electric vehicles."

I wish there were more coming next year instead of 2028. 2028 is currently the forever "5 years away from production" in research lol

[–] [email protected] 1 points 11 months ago

Maybe, but there's still a lot of energy in them and if things go wrong that energy can be released. They're probably an improvement but good standards of manufacturing etc. Are still important

[–] [email protected] -1 points 11 months ago

Lots of people think they are home mechanics and like to maintain their own vehicles. Lots of business that are Mechanical workshops are either unqualified or should not be qualified.

This is not too big of a problem when all you have is 12V power, some diesel or some petrol. You may get a light electrical shock, some chemical burns if you have sensitive skin if you don’t know what you are doing. The most dangerous damage they will do to your car is suspension or brake failure while driving, or an underbonnet fuel/electrcial fire or an in-cab electrical fire. These fires can be put out with powdered fire extinguishers. If a Pb-Acid battery ruptures, you may get some nasty acid burns.

When someone who doesn’t know what they are doing, fools around with an EV, Hybrid or newer ICE car with a 48V electrical system, they can do much more damage. Damaging one of those orange cables can instantly get the coroner involved. When a cell gets ruptured in certain lithium chemistry batteries, the location of the fire will be inaccessible for days or weeks because we have no fire suppression technology that can put that bugger out.

We need to halt (or at least cut down) burning hydrocarbons for fuel, but everyone swapping their oversized ICE Sedan or SUV for an oversized EV Sedan or SUV is not the solution.