Hello all. Tried to search this the best I could, but no total luck. I have an e-350 1990 ambulance I bought. It has two batteries under the hood. It runs to a master disconnect/kill underneath drivers seat. This master switch kills everything to the truck. From there I also have a switch on the ambulance siren/lights panel that is a master for the box. If I wanted to have a dedicated battery bank charged up by the alternator, and have the box run only off the new battery bank, what would be the way to do all this? Apologies if this was discuss somewhere else, but I cannot find it super clear.