|Geoff, you might want to check out the 18500 size Li-ion battery (3.7V, 2,000mAh). Two of these might fit, one mounted on the chassis cross-member that rests on the rear truck and the other near the middle of the chassis behind a motor that drives the front truck. I believe there are 18350's available, but don't know the battery capacity.
There should be enough space above the motor and/or forward battery to mount a Rx/ESC, maybe also room to step-up the voltage. With Hobbytown's drive arrangement, I have this type of room, but with Athearn, and especially Atlas, there may be no room at all. Might be worth a try, but suggest you lay it out on paper first.
Last edited on Thu Nov 2nd, 2017 07:30 am by dan3192