I have a '99 pt185. I have room for three batteries on the port side of my fuel tank. I'm not sure what group they are, but I can tell you they are the largest deep cycles in the walmart brand. Also, the TM mounts on the boat should be plug and play with minnkota and motorguide. This summer I put a minnkota edge 45 on and it fit with no mods. I have since gone to a used 56 lb 12/24 volt motorguide, but will be selling both to pick up a 24 volt 70 lb. Motorguide. In a stiff wind the TM is on 4 just to stay stationary, 5 to move at a snail's pace. Bass trackers and wind don't get along good.