The Flightpower Evo25 V-Power 2170 mAh 3S 11.1v werks awesome in mine. 25C cont., 35C climbouts, 50C max burst. With my solder job and EC3 connector, pack comes in at 174g. I've also got an Absolute Power Xtreme Lite 2500mAh at 18C and 45C burst, not exactly the same but it hasn't skipped a beat either. Its 176g.