I purchased all new batteries for my coach and chassis. I hooked them up and went to test the slide. The slide worked as it should but my son was standing by the battery compartment, which is still open and said the chassis battery seemed like it was boiling. It was and seemed to be getting worse by the second. I quickly unhooked the ground and it stopped. What caused this? I am 99.9 percent positive it is hooked up correctly.

were you plugged into shore power? I would verify the battery hookup. On trailers it's usually black is positive and white is negative. I'm not sure if that holds true for motorhomes. Do you have a meter that you can use to do a continuity check between the wires you were using on the negative post and a good ground point? you should have almost no resistance with that measurement. If you are reading high resistance or even OL you are checking a positive wire. make sure you are checking the wire to ground, DO NOT put either probe on a battery terminal or you'll blow a fuse or fry the meter.

Tell us what batteries you have and how they are hooked up.Sure sounds like a mis-wiring! Perhaps something like charging a 6 VDC as if it was a 12 VDC.

Did you take a picture of the cables ? Replacing batteries seems so simple but it seems like when someone doesn't take a picture and draw a diagram too they inevitably get mixed up . Before changing the cables take a picture and post it here . The folk here are so helpful and they will help you figure it out . I would not hook the batteries back up until you resolve the issue . You may have a defective charger that is charging full blast . At any rate a boiling battery is dangerous .

Unfourtnaley no I did not take a picture. I did of the two deep cycle, but not of the cranking battery. But I don't think I got it wrong. Since there were only two to one post and they are connected together and one to the other post. I'll get a picture tomorrow.

I did have the motor home hooked up to regular outlet at my home for lights in the rv. But did not have it cranked.

New Battery boiling | Good Sam Community

time2roll
Nomad
May 22, 2019
Looks good, need voltage.
MrWizard
Moderator
May 21, 2019
duplicate
MrWizard
Moderator
May 21, 2019
mxdad290 wrote:
Another shot of battery hook up...ground is unhooked.
MrWizard
Moderator
May 21, 2019
mxdad290 wrote:
mxdad290
Explorer
May 21, 2019
Another shot of battery hook up...ground is unhooked.
mxdad290
Explorer
May 21, 2019
One picture of my battery hooked up
mxdad290
Explorer
May 21, 2019
[img][/img]
Gjac
Explorer III
May 21, 2019
Double post
Gjac
Explorer III
May 21, 2019
Your profile says you have a 1999 MH, most MH's don't charge the chassis battery when plugged into shore power unless you or a PO installed a charging wires running from the house batteries to the chassis battery or a separate battery charger just for the chassis battery. Is this what you have? If that is the case the wire going from the house to the chassis battery may be reversed. All your main wiring could be hooked up correctly as you stated. Before you changed batteries did you chassis battery always charge when you plugged into shore power? Check the voltage coming out of your converter/charger what does it read?
ArchHoagland
Explorer
May 21, 2019
Do you have a voltmeter?