The battery is right under the cockpit as far back as possible it can go. Heres the thing, the battery is 4oz in weight. 3000mah Li Ion. 3" wide, 4" long and 3/8" thick. Nothing can be moved back further. i was thinking cutting the ultracote under the rudder on the bottom, inserting two weight bars on the sides with securing them using CA and kicker and re covering the small hole I had to cut. Sound ok or no? I used the Dave Brown nylon mount for a .60 engine. Weighs less.