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alexiskai · 09-30-2021, 12:03 PM

My understanding is that there's no danger jump-starting a 6V pos-ground system with a 12V neg-ground battery so long as you only leave the 12V connected for the few seconds required to start the car. The danger to the ammeter and coil are in heat buildup, and they're just not going to accumulate enough heat to do anything in a few seconds.

09-30-2021, 12:03 PM	#2
alexiskai Senior Member Join Date: Apr 2018 Location: Mebane NC Posts: 2,360	Re: Jumping 6V with 12V battery My understanding is that there's no danger jump-starting a 6V pos-ground system with a 12V neg-ground battery so long as you only leave the 12V connected for the few seconds required to start the car. The danger to the ammeter and coil are in heat buildup, and they're just not going to accumulate enough heat to do anything in a few seconds.