Boiling battery

tdsingletree

I have two dealer-installed 12v batteries in series. While connected to shore power, one of the batteries overheated, boiling water out of the top. The other battery only got warm. Did I do something wrong or do I need to have the dealer double-check his work?

JamesDow

Two 12 volt batteries connected in series would put out 24 volts. I would think (hope) they are hooked up parallel.

tdsingletree

Maybe I've misspoken. The dealer connected two batteries together for the purpose of providing more off-grid capacity. I said "in series" because that's what I thought it was called.

JamesDow

I would advise taking back to dealer who installed (if possible).

Sounds as if you have a malfunction in your charging system which is causing too many amps being delivered to your batteries. If the dealer installed two 6 volt batteries in parallel, this could also be the problem. Boiling batteries can put out flamable gas so be aware.

Bob297

Not related….but 2 decades ago I had a truck battery boiling (overcharging) because of a bad alternator.

I agree with JamesDow, take it back to the dealer.

Michigan_Mike

Can you post up a photo of the battery wiring?

tdsingletree

ras

Two 12VDC Deep Cycle Marine batteries that appear to me to be correctly wired in parallel. Problem must be in the charging system or a bad battery (internal shorted plates?). If your dealer's close, take it to the dealer. Or take it to an Interstate Batteries dealer. They'll test the batteries for free and replace under warranty if one is bad.

tdsingletree

Update: I removed the cooked battery, leaving the other one connected. Powered everything up and there were no issues. Took battery to Interstate dealer. They're exchanging it at no cost.