Hey Guys. I have a Tradesman shell on my truck that I'm converting to a camper. I want to put an auxiliary battery back there for a stereo and some lighting. My question is how to hook it up to the truck's charging system. My concern is that I'll drain the cranking battery. I'm not sure if I need a charge controller or an isolator or what. I'd like to charge the house battery off the alternator, then have it isolated while i'm camping, so that if I have too many beers and leave music blasting all night long, I can still get the old girl started and get on my way in the morning.

-Thanks!
Max