I installed an isolator on the truck and ran size large battery cables to connect the deep cycle camper batteries with a rated quick plug. I disconnect the “12v +” little wire in the camper plug. Automotive alternators taper the charge as battery resistance increases as they charge. I would make sure to connect the converter charger to 110 ac once in a while so the batteries recurved a full charge.
I expect there are fancier isolator/chargers available nowadays that will alternator charge deep cycle batteries properly
