house battery install, basic

If it were me I would purchase simple battery isolator solenoid as outlined in enblethen first post. Suggest you run a 16 gauge wire from the accesory post through your fire wall connecting to your radio fuse (via piggy back fuse available at any parts store) - this will energize the solenoid anytime you turn the ignition on - once energized the solenoid will connect house/chassis batteries. When the ignition is off the solenoid will keep the batteries separated.

I would also purchase an inexpensive Trik L Charge - simple device which will allow charging of both house/chassis batteries when your plugged into shore power - Easy Google.