Harhumph, Wow, and I thought I was the only crazy one here running my stock CP Pro Eflite 800 mah 3 cell battery in my CX2 as an "Everyday Driver" ! It weighs in with velcro attached at 65 grams. Have you ran a 3-cell yet in the CX2? The reason why I ask is that with this battery of mine the power is so insane, I've never was able to "floor it" as I accelerate to a lift that is so intense it's hard to put into words. I couldn't imagine something bigger !? I've never had a problem running it except for once. My 4 in 1 is vented with a dremel nicely that it is just about the square frame that's left, and I cut the crap out of the plastic, trying to make it somewhat decent, all around the engines just to have a little reasurance to keep things "cool" in which they do.I can touch the actually chips in the 4 in 1 after running this 3-cell and they are barely warm. my batteries, 2 stock eflites 2 cell, 2 mega packs 2 cell 850 mah 15c, and of course the 3 cell all are just barely warm after running. Engines-just warm, not hot. When I have my 3 cell in the bird it currently weighs 260 grams. Some would say thats a lot of weight, including the little voice in my head, but if you saw how the chopper performs, you would never guess. Your gears will slowly take extra wear and you'll slowly develop "play" between the teeth of the gears and the pinions I have noticed. I shoot videos frequently, but need to figure out where I can put them and how to "display" a link on here among that, so maybe I'll try and figure it out so people can see how much upward thrusts it puts out. I have 5 L.E.D.S, and the one problem I did have once, as I stated above was when I had them "plugged in" and was firing up the 3-cell and I had some power glitches w the 4 in 1 flashing red and green really fast blinking and letting the bird drop very gradually. It made me nervous because people on this forum have fried there 4 in 1 from running that extra voltage through the 4 in 1. Luckily everything was o.k. and from then on, I never run my lights with my 3-cell and have never had a problem since. And I do run it a lot. It makes me wonder if I'am right on the border-line of what the 4 in 1 can handle. Flying in the wind is incredible, way better results than with a 2 cell, power to weight ratio is excellent in my mind and I have a lot more control when I'am outside. But then the more the heli weighs, the more it's gonna hurt when it falls. The battery you mentioned above if it did fit makes me a little nervous I think I saw that it was in excess of 1,000 Grams I hope I read that right, because that just seems like it could be overkill and the 20c along with that. This is just my own personal opinion though, I just don't want you to hurt your heli or anything. I think my stock 3 cell E-Flite puts out 10c, but it feels like it's way way more ! That extra cell is a considerable differance! Maybe to be safe if you haven't tried a 3 cell start small (3-cell) and work up at your own risk... The 3-cell I've been talking about runs usually around 37.00, but I also think E-Flite's batteries run a little to much. I feel like I'am writing a book ! lol !I just don't want a new guy slapping in a 3-cell without knowing the risks involved, but like I said I've never had a problem, and my best friend also has a CX2 and he runs his CP PRO battery in his and he's crazy he'll just shoot it about to the moon, I barely can see it in the sky it's so far up! [X(]One day that wind up there is gonna snatch that sucker and send it to the next town over I swear! Anyway, just my 2 cents! Good luck experimenting, and please keep us informed, because to me this is a "HOT" issue, because I believe these little birds can handle more than what people might think...(with the right set-up) Take care bud, --Jeff