[C320-list] Battery problem

[Mike Paris]

I use 2 Interstate flooded deep cycles and Xantrex 20a charger that are all 18 months old. The auxiliary battery went dead and when I checked it the cells were very low on water. The main is fine. After refilling, the charger has been on for 48 hours and the aux shows only 7 volts. The aux battery sounds like its cooking while the charger is on. I'm going to have it tested tomorrow to see if it's dead. The main shows 12.7 volts. These readings are from my LinkPro. I want to find out what caused this. 

With all switches on the panel off, the LinkPro shows 0 amps being used. When I turn the charger on it shows 4.8 amps being used. Is the LinkPro connected wrong? What could cause dc amps to increase w the charger on? I've checked every dc switch on the panel and they each register a change on the panel when they are turned on or off. 
What's the next step? What caused the aux. battery to fry?

Thanks,
Mike P
#734