[MENTION=101314]sr3tlaw[/MENTION] [MENTION=67786]4RunAmok[/MENTION] B smart, I have ran down a dual battery system with NO isolator and killed it, no start; and it (the 4runner) charged everything fine. Yes, it will MAX higher (i believe double, 160amp), but I don't think any of us need any more amp than the stock alternator puts out. I only ran 6gauge from battery to battery. Is there a place I need to run bigger gauge wire than what comes stock on my truck?