New rigger is in the works so I made a couple of new battery packs. The cells I used is the new type of "Instant" NiMH type that are charged and ready to go when delivered. The self-discharge level is very low also. The brand name is Vapex Tech and they are called "Instant" - the capacity is 850 mAh. Thats plenty of power for a 3.5 cc rigger. Do note, they dont like fast charging so much - my suggestion is to charge them with no more then 0.4A (I use a Great Planes Triton charger).