House battery boils

[Woof]

Have a 2002 Winnebago Adventurer and this last summer in Utah we had to buy a house battery (12 volt)to go with the other battery that was good. Our engine battery seems to be all right. The newer house battery is boiling, lots of smoke. I added water this morning as a couple of the cells were low. I called a local RV repair and they said the house batteries were unbalanced and the newer one was doing all the work. That was not the case after I got the new battery. The older one seems all right, full up with water. I usually have the RV plugged in so I unplugged it and the battery still boiled. QUESTION: Could there be anything else causing this problem? Right now I'm going in Tuesday to the RV shop and I'm sure they are going to put in 2 new house bateries. Thanks in advance.

[Woof]

Have a 2002 Winnebago Adventurer and this last summer in Utah we had to buy a house battery (12 volt)to go with the other battery that was good. Our engine battery seems to be all right. The newer house battery is boiling, lots of smoke. I added water this morning as a couple of the cells were low. I called a local RV repair and they said the house batteries were unbalanced and the newer one was doing all the work. That was not the case after I got the new battery. The older one seems all right, full up with water. I usually have the RV plugged in so I unplugged it and the battery still boiled. QUESTION: Could there be anything else causing this problem? Right now I'm going in Tuesday to the RV shop and I'm sure they are going to put in 2 new house bateries. Thanks in advance.

[paz]

Batteries should be the same type (AGM, wet cell, etc.), age, and condition. If one battery is older, even though it is in good condition, it will drag down the new one. IMO you should have replaced both batteries when the first one went bad.

While your motorhome is in the shop, they will probably check the output of the converter/charger to make sure it is not putting out too much voltage. If not, I would certainly ask them to do so just to be sure there is no problem there.

Below are two sites on batteries which I have found to be useful.
http://www.phrannie.org/battery.html
http://www.ccis.com/home/mnemeth/12volt/12volt.htm