Texas 3D, when Jeff Williams visited me, and we flew together, he was telling me that he was running the 720 mA NiMH batt. packs in his Fun Flys. The 720s are AAA batteries. You wouldn't believe their physical size and weight (or lack of it ). I believe that Jeff was saying that he was getting 4-5 flights on a charge. So I bought some from Radical RC. I have yet to install them, but if they perform like Jeff claims, there will be a significant savings! I am already running the 1650 mA NiMH packs in my Ecstasy, and some of my other Fun Flies. I am going to switch over to the 720s as soon as I catch up. I'm getting getting for a couple of shows right now. I tried to put a 720 pack in my PBXL last weekend, but I use the batt. to balance it. When I positioned the 720 NiMH batt. into position to balance the PBXL in the same location I had it with the 1200 mA NiCad, the 720 pack was sitting on the elevon! Needless to say, it didn't go there. I'll have to figure out something else.
Just offering some 'food for thought'.
Kevin