I have been working on EV stuff for about 20 years now. For anyone interested here are my thoughts on safety related things:
1) Biggest worry is mechanical injury. As a design engineer for the drive system I work together with people assembling, testing, and maintaining the prototypes -- people such as mechanics who are used to combustion machines. One of the projects I worked on is a tunnel rescue vehicle in Croatia:
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While I was working on it there was a guy underneath it close to the drive shaft. I said "I'm gonna power up the system now, don't be underneath the vehicle anymore." He said "Why? Is it gonna shock me." I said "No, it won't shock you, but if I made a software error it might wrap you around the drive shaft." Remember Brian's videos where the cooling fan was running "for no reason?" Well, now you know the reason; everybody involved still has all their fingers. The bike "dropping out of gear" when not moving is the reason why the fan no longer constantly runs. Anyone notice that those two changes came in the same software update?
2) Second biggest is fire. I don't have access to statistics but I think a large percentage of e-bike fires are caused by a run away charger. However, fires can happen even when not charging. Once the fire starts the battery will become a chemical oxygen generator and there is little that can be done to put it out. The tunnel rescue vehicle above uses LiFePO4 cells for that reason; they start releasing oxygen at a much higher temperature than more energy dense chemistries. However, I am less concerned about fire on a bike (you just get off) than a car. People have been burned alive in car fires because they could not get out, even in gasoline powered cars --
Woman Killed After Car Locks Her Inside and Catches Fire | Entrepreneur
3) Electrocution is a distant third. Fear of this comes mainly from people not understanding the flow of electricity. Let me explain:
For you to get electrocuted you need to be part of the circuit. Electricity must flow _through_ you. Now with grid power the system is earthed/grounded. This means that you only have to touch a conductor at _one_ point for you to get electrocuted as the electricity with flow from the point where you touched the conductor, through your body, out your feet and into the earth. The _earth_ completes the circuit. For EVs with high voltage the main battery is not connected with the chassis. This isolation is an integral part of the safety of such systems and it is monitored. If you are doing your own system you can buy a board such as this:
The ISOMETER® iso-F1 IR155-3203/-3204 monitors the insulation resistance between the insulated and active HV-conductors of an electrical drive system (
Un = DC 0 V…1000 V) and the reference earth (chassis ground > Kl.31).
ISOMETER® IR155-3203/IR155-3204
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I've done my fair share of work on live 300V+ systems for close to 20 years. I'm still alive for a reason.
Just about everyone understands being burned or having your fingers go between a chain and sprocket, but most people don't understand the flow of electricity so that brings both unfounded fear and unfortunately sometimes mistakes.
Anyways, those are my two cents.