Originally Posted by mlmarch
85 345. first inline house battery(of two) gets hot(second battery does not) when unit plugged into land power. batteries are wired positive to positive etc. what is the cause-do i need to turn the switch off in the battery compartment each time i plug in? i read the thread on boiling batteries in 2004 but no info contained on this issue.
Hmm. Try disconnecting both batteries from each other, and from the charge lead. Check the voltage. If they are both at least 12.65 volts, they are fully charged. But my guess is you will find the battery that is getting hot will be seriously under voltage. This can be from a number of things, but the two most common are: The battery has a bad cell, and either the cell is draining the battery while unplugged, or it is shorted internally, causing a lot of heat.
The other possible cause is the battery that is not getting hot has a bad connection, either externally (cable end) or internally (open in a cell). It is just sitting there, allowing the other battery to power everything in the coach, and, of course, bear the brunt of all the charger's recharging efforts.