Crap! Hoping my batteries aren't damaged. Decided to redo the original battery location on the tongue. Cut and rewelded the brackets to accept two batteries. Wired the charge controller to mount inside the camper close to the tongue. It's all been up and running great for about 3 or 4 weeks now. That little 54 watt panel I currently have connected keeps them charged at 14.7 volts. I'll add more panels when camping. Saturday nights my wife and I spend about 4 - 5 hours in it. During that time I turn the furnace on. I noticed when the furnace is running it uses the 12 volt power. Even though the 110 is plugged in. If I disconnect the batteries it uses the 110. Seems completely backwards. Note #1. Also seems backwards. So last weekend when I went to fire up the furnace the blower didn't come on. Realised right away that I had forgot to turn off the thermostat the prior Saturday night. Turned the propane off just not the switch. Checked the charge controller voltage. 4 volts. Crap! Disconnected the batteries and hooked up my 10 amp charger. Now being a prepper on a budget for many years I have alot of experience with both maintaining and reconditioning used lead acid batteries. Normally I can tell how good a battery is by how it accepts a charge. Good drained batteries will accept a charge starting at 10 amps and slowly drop the needle on the charger down to zero when fully charged. When the meter drops to around 2-3 amps I'll switch it to 2 amp charge for the remainder. My charger has been on since Saturday and the meter isn't dropping past 5 amps. I checked all the cells and they seem to all be bubbling at the same rate. Damaged batteries will show one or more cells bubbling at a much slower rate. So I'm not sure if I damaged them or I just haven't charged them long enough. I did hook the solar back up tonight just to see. The controller is reading 14.1 volts. So a couple of things I need some input on 1. Feedback on what to do with the batteries. Keep solar connected? Hook the charger back up or exchange them? 2. Master switch on the 12 volt main? I'm sure this isn't the only time I'll forget the thermostat switch. Plus it's hard to believe the furnace is wired that way. Seems like it should run on AC on default. I can't tell from the schematic if it supposed to do that or not. All the wiring on the camper is original with the exception of the charge controller and panel wiring. I would have assumed there would be a way to disconnect the 12 volt system or at least have a built in charger that would automatically kick in when 110 was hooked up. Well... It's best to discover these things now and figure them out before I actually use it. So that's a plus. But argh!