GC741969

When you say isolator, are you talking about a manual switch or a diode type of system so current will only flow from one battery if desired??

I cant imagine why you would need a bigger alternator to trickle charge a second battery while driving the truck, it would be no different than towing something with lots of lights and its own battery to charge. And why bother with battery isolation unless your not using the vehicle for long periods of time?? You'd want to wire it in parallel to double the current not the voltage, right? And would that extend the endurance of your trucks power systems when its not running while your parked someplace with the radio and internal lights and bed light running for long periods of time??