Reply To: EV hints and tips

#309375
MFillingham
Participant

    I recorded that, thinking I’d see what a few EV groups made of it and whether it lived up to my rather bleak expectations.  Due to popular opinion being it was a waste of airtime if truth was anywhere in your remit, I deleted it without watching.

    There are issues, which you can easily make a mountain out of at will. For example, the fire thing.  I’m sure @kezo will happily correct me but it’s really quite difficult to set a car battery on fire, mostly because it’s in a rather strongly built aliminium box with steel bits for extra strength, meaning it’s not going to simply snap and combust in a collision.  However, once you get it burning the chemistry is such that it’s an absolute ballache to stop burning again.  It’s both hotter and better fed, meaning it’s not just going to burn off however much liquid fuel is around until the fire brigade cut off it’s oxygen supply.  Car batteries will, simply put, maintain their extreme heat for hours and hours after the oxygen has been cut off and will easily combust again if oxygen becomes available.  You can smother it, like then do petrol with foam, the problem is that foam doesn’t last particularly long, so when the foam breaks down, the heat is still there for more fire.  Putting a large fire blanket will work, it’ll cut off the oxygen for as long as you can keep the edges sealed but that isn’t as easy as it sounds and you’d have to leave the car there for many hours before you can lift he blanket.  Huge water baths have been used, again the water both cuts off the oxygen and provides limited cooling.  Insert burning car into bath, leave for a day or two and all is good.  Not the most practical roadside solution.

     

    What isn’t clear is just how much of a problem is this in real life?  There’s insufficient data, due to insufficient cars having accidents resulting in battery fires, to say just how much of a problem this really will be.  What is known is that, should the unlikely happen, the result is a real problem and has no simple solution.

     

    We know a lot about safety concerns of ICE vehicles, we can easily transfer a lot of that to EVs as they’re pretty much identical on the outside, so pedestrian safety, collision systems, crumple zones and all the other things they’ve done are transferable, it’s the electricity and battery specific dangers that are a problem.  Does any EV driver know where the cut off switch is for the HV circuit?  I know for sure I’ve no idea but if an accident happens and the big cables are exposed, it’ll be bloody essential to cut power to those cables as 400V and a lot of amps will do a lot of damage to anyone who comes into contact with those cables or anything in contact with them.

    I'm Autistic, if I say something you find offensive, please let me know, I can guarantee it was unintentional.
    I'll try to give my honest opinion but am always open to learning.

    Mark