I am currently installing solar panels on my SO 389. I have 3 house batteries in the aft portside storage locker; two under the floorboard and one under the tool drawers. I am not sure how to connect the output cables from the charge controller. Is it OK to connect them to the positive and negative on the battery under the drawers only or should I be connecting them to all 3 batteries, and if so how? Any advice is appreciated.