Randy, not an EE and no expert. But in my Top Flite 60 size Mustang I had to mount one battery all the way back in the tail, behind the tail wheel (ign.) and the other just behind the wing saddle (radio). I tried to keep the wires to the ignition battery as far away from the radio as possible but in that narrow fuslage, still close. Ing. modual is up front just behind firewall. Radio is towards the rear of wing. Using Futaba 2.4. 220 flights on the plane and no problems so far.