i highly reccomend going with 5 cell packs(6v) I wont fly with a 4.8 pack anymore. Goodluck though ...... I use this pack in all my 40-120 size birds http://www3.towerhobbies.com/cgi-bin...&I=LXNHS4&P=ML

Not too long ago during a preflight check my 5cell pack read 6.7 or so volts , then after the flight it read about 5.6 (cant remember exactly) ....turns out i lost a cell, i didnt bother to examine each cell to verify, but everyone at the field agreed and said i was fortunate i use 6 volt packs