The snow is melting and I'm beginning to formulate plans for getting our cargo van converted for our 2 week trek to Maine in October. I'm installing a 110 ah 12v battery as the auxiliary battery under the van and later on I may hook up another in parallel if I need the additional reserves. Just plan on running some led lights and a 50 quart ARB fridge. I'll be hooking it up to shorepower as well as letting the alternator charge them when the vehicle is running. I understand I need an isolater switch between auxiliary batteries and the cranking battery . When charging auxiliary batteries with shorepower would I isolate the cranking battery? Would I somehow damage it if I did not? I plan to run the shorepower wiring through the rear bumper. I know some people on the forum have done this so any link appreciated. Lastly, any recommendations for AC/DC transfer switches appreciated.