[Richard]

Steve,

Here are some things to think about. First, if the battery has a CCA number on it, that is a cranking battery. And although it will work just fine in the house battery bank, they are not designed for deep discharge. They will work just fine for running the fridge off the inverter, but not very good for boondocking. I may have misinterpreted your nomenclature when I read "coach" batteries. I am assuming you meant the house batteries, and not the cranking batteries.

In my experience, batteries boiling usually is associated with one bad cell in one of the batteries. The charger is supposed to taper the charge based on voltage. One bad cell will drag the voltage down enough so that the charger thinks the batteries are not charged. Of course, stopping the charge cycle, letting the batteries sit for a couple of hours, and measuring the battery voltage will tell you a lot. So, would hydrometer readings on all the cells.

I would also check the Xantrex settings to make sure that the charger is not in the Equalize mode.

And I may be dead wrong, but I don't think the amp hour setting in the charger has much to do with how much amperage the charger puts out. This is easy enough to check, look at the charger amperage output, then change the amp hour setting and see if the amperage output changes.

If the batteries are cooking in the float mode, I really think something else is going on.