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Charging a car battery question.

by perplexabot
Tags: battery, charging
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perplexabot
#1
Feb10-13, 02:46 PM
P: 248
Hey. Was jump starting and charging a car battery a couple of days ago for the first time. I connected the positive of the bad battery to the positive of the good battery, then connected the negative of the good battery to a solid metallic, non-painted part of the engine on the bad car, or the body frame.

My question is: How is this a closed circuit? Is the negative terminal of the bad car's battery connected to its "solid metallic parts/body frame?"
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marcusl
#2
Feb10-13, 02:48 PM
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Yes, the negative is grounded just as you said.
perplexabot
#3
Feb10-13, 02:57 PM
P: 248
Quote Quote by marcusl View Post
Yes, the negative is grounded just as you said.
Thank you for the quick reply. My mind is now at ease.

perplexabot
#4
Feb10-13, 03:01 PM
P: 248
Charging a car battery question.

Ok now a follow up question if you don't mind. Why then not connect the good battery's negative directly to the bad battery's negative?
marcusl
#5
Feb10-13, 03:30 PM
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Batteries produce hydrogen gas bubbles as they charge, and this can be vigorous for a fully discharged battery. Connecting to chassis ground keeps any sparks away from the battery and flammable gas.
perplexabot
#6
Feb10-13, 04:00 PM
P: 248
Thank you.
jim hardy
#7
Feb10-13, 04:35 PM
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Follow your battery wires.
Most GM cars have a positive post near the battery for jump-starting. It'll be underneath a red plastic pop-up cover.
Sure easier than trying to grab that battery side-post terminal, and safer too as marcusi pointed out.

I like to connect negative to a substabntial piece of metal on the engine. I figure starter is bolted to engine block, so starter's heavy current doesn't have to flow through a potentially weak frame wire on its way back to my jumping battery's negative..


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