I have a 35 foot Super C. Two coach batteries. As of this week, I will have destroyed two sets of batteries. When I am plugged, the Xantrex monitor reads 13.1. When driving, it reads 13.6. The generator usually reads 13.3. I check the water at the beginning of an 1300 mile trip to Florida from NY. I plug in and checked the water for the trip home. One battery was very dry and the other just a little low. Batteries now can't keep up with electric refrigerator for more than an hour. Could batteries be overcharging? Should I be adding distilled water more regularly? Is the electric refrigerator a power hog? Are there other kinds of batteries that work better. This is a 2015 and I will be going on a third set of batteries. Not happy.