Battery box 29

With some modifications you can fit 3 group 31 batteries in the box. You load them from the center and push to outside. With a US battery group 31 rated at 130 amp hours. This will give your house bank 390 amp hours. Then I put a group 24 in a battery box secured with a quality strap behind the cushion just above the house bank. This serves as the auxiliary which is seldom used.