Hey Near HIt, I am also running separate batteries on my 20 cc Evolution engine and have no problems with it. I am using two 2000 MAH 6V NiMh batteries similar to the single battery I am using with the 10 cc engine. Yes, I checked the condition of the batteries before I installed them. All three were in very good condition. It seems as though the ignition using the IBEC is using a great deal of juice in a short period of time. I am not sure if that is due to the IBEC or the ignition but changing to a second battery should tell the story.

Heli-NuBee (AKA Roger the radial rabbit)