I am looking at adding a second deep cycle trolling battery so I can run 12V in parallel (I think thats the right term). The boat is a 2008 Triton TS18. There is not enough room to fit two large deep cycles in the rear hatch because the on-board charger is where the third battery would be mounted. No other suitable place to mount the on board charger. There isn't enough room next to the other deep cycle to fit two side by side. The trolling motor is a 12V M/K PwrDrv 55lbs 48" US2/AP.

Question 1: Are there any draw backs or don't do's to installing the 2nd deep cycle up front in a rod locker that I don't use for anything else. I could run wires from it back to the other deep cycle to get the parallel connection. The distance from one to the other would be +/- 7 feet. The back battery already has the connections w/fuses that go back up front to the trolling motor. It is all in the factory harness that I would rather not try to untangle.

Question 2: 6 or 8 gauge wire for the parallel connection?

Question 3: Will the on-board 2 bank charger that is already connected to the back deep cycle be ok for charging both deep cycles while in parallel? I think it is a 5 amp two bank.

Any other tips, ideas, or warnings I may need to know?