Batteries: a 12 volt jumping a 6 volt

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jaybee47
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Batteries: a 12 volt jumping a 6 volt

Post by jaybee47 » Sun Jun 04, 2023 9:43 am

I witnessed a man jump start his 6 volt battery with a 12 volt battery for his T at a car show. He said his 6 volt battery was dead and his arthritis was hurting so he couldn't arm crank. He connected the 12 volt battery via jumpers. The T started immediately then he disconnected the back up 12 volt battery right away. QUESTION: what harm was done to the T's electrical system, if any?

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DanTreace
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Re: Batteries: a 12 volt jumping a 6 volt

Post by DanTreace » Sun Jun 04, 2023 9:56 am

Probably none, if stock T system. If a distributor then that single 6v coil might have fried! Or if the lights were on, the lamps would blow!

Safer way, to protect the 6v storage battery is to hook 12v battery positive jumper to the 6v positive on battery, then the 12v battery negative jumper to another ground on the chassis, away from the 6v battery to prevent/risk any destruction of the 6v battery. Best done by 2, one connects the negative as the other hits the starter button, and when started, the one disconnects the negative jumper immediately.
The best way is always the simplest. The attics of the world are cluttered up with complicated failures. Henry Ford
Don’t find fault, find a remedy; anybody can complain. Henry Ford


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Re: Batteries: a 12 volt jumping a 6 volt

Post by Been Here Before » Sun Jun 04, 2023 10:01 am

Jumping a 6 volt system with a 12 volt battery can be done. But there are dangers.

The one that is always there, is one or both of the batteries exploding from a spark and the batteries gassing.

https://www.latimes.com/archives/la-xpm ... story.html


Kerry
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Re: Batteries: a 12 volt jumping a 6 volt

Post by Kerry » Sun Jun 04, 2023 5:15 pm

If the 6v was dead flat, the safest was and easiest without dicking around under the floor boards, is switch to magneto and just jump the starter motor.

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