Best Posts in Thread: Car service on Sunday, Dumaguete

You will always find different opinions on if the good car should be running or not.

Always check the owners manual and some manufacturers do not allow jumpstarting the vehicle at all.

I spent most of my working life running large accident repair shops that repaired mainly Toyota, Audi, VW and Mercedes. In almost all our training it was engine off.

Electronics in newer cars are very sensitive and extremely expensive to replace. Jump starting with the engine running can cause a spike in current.

We would even disconnect not just the battery but all the computer modules when doing welding.

Remember reading a trade journal of the donor cars air bag going off when jump starting. Expensive jump.

Best to use something like this.

• Built in surge protector guards sensitive vehicle electronic components from voltage spikes

https://autobarn.com.au/ab/Autobarn...12v-400amp-Spike-Guard-Jumper-Leads/p/EL31722

 

Why is that? I always saw the opposite (start working car before trying to start failing car) being suggested so far. Which makes sense to me as a running engine gives 14V, vs 12.6 or so if you just use a charged battery.

In case of using a motorcycle to donate power, I’d definitely say it should be running - the small battery alone might not be enough to turn over your car’s engine.