well I stopped by my battery dealer and swapped out the big deep cycle for one that fits in my battery bay. the posts are backward from what I had so it was a tight fit to get the cables to fit
I also added the charger and mounted that in the car. after I see how its working I will need to add a second 120v plug on the side of the car. I am thinking of trying the starter battery as the second one, but I will wait and see how the deep cycle works fist. it has less cranking amps (640 vs 690) but a longer reserve (140 min vs 100). it is also designed to be drained more then the old starting battery.