Ok, so my daughter bought a 2006 FEMA trailer recently. I believe it's a Fleetwood Pioneer. The lights kept going dim and then the A/C would not come on. I found that the battery was out of juice, so I swapped it out with the one from my camper (we stay next to each other). A few days later, same thing happened. So I know the battery is not being charged. I checked the fuses and they are all good, so I don't know what the problem is. I also don't understand why my 12v lights still work when I unhook my battery to swap it with hers, but her lights go out with her battery unhooked. From what I have read here, it may be the converter, but I'm not sure. Is there a way to test it? Can I use solar power just on the battery to keep it charged? Thanks for any help you can provide.