Hi all, last year my camper started having power surges with the lights and fans, the lights would get dim then a couple minutes later back to bright continuously. We just camped this weekend for the first time this year and it continued doing it but this morning the ac or furnace won?t try to come on, the lights hardly light up and all and the one vent fan won?t work at all the one does slightly. I also noticed it drained my battery down to 1 bar, why would it drain the battery when it?s plugged in to a 30amp service? My battery is 4 years old and was corroded so I brought it home to clean up and charge, the refridgerator and outlets still work fine as well as the microwave so what could be causing this to only certain things?