Soo.... I previously had my 30A converted to a standard plug, so that I could plug it in the side of my garage. I also had the camper set to 120V however I switched it to 12V unplugged the cord and went to see if anything would turn on and to my surprise nothing. I'm going to leave it plugged in overnight and try in the morning to see if I can get a light or fan on without it plugged in. Does the battery charge if I leave it to 12V and leave it plugged in? If yes, why is a battery minder/tender needed? Assuming my battery is shot (I'll take it to pep boys to get it checked) is there a clear favorite by a big margin in the forum that I can set my sights on to buy?