ORIGINAL: Andrew McGregor
I think you just didn't have a big enough battery capacity and browned it out.
You are confusing capacity with the ability to deliver voltage under load. Capacity has nothing to do with that. For instance I have some 1400 NiMH packs that have a very low internal impedance. Under a 1 amp load they will drop about .2 volts. I also have some 2700 NiMH packs that will drop nearly a full volt under the same 1 amp load. Twice the capacity, and nearly 5 times the voltage drop. It ALL has to do with the internal impedance of the cells in the pack. Bigger capacity does NOT always mean better performance.