I'm using a pr od NeuEnergy 5000 2S lipos to run both my Emaxx and FLM converted Emaxx. The Emaxx is still running stock Titans and the FLM Emaxx uses a Feigao 8XL. I get 12-15min or hard running with a few high speed passes. I still have 4000 and 4400 7cell NiMH pacs for the Emaxx but they hardly get used anymore, the feel and balance of the Emaxx is better with the lighter weight using lipo. I've converted to lipo for my tx also, lighter and lasts longer than either alkalines or rechargeable AAs.