Yeah, and for a given pack size.. both being the same mah rating (not that they are, but if they were), the 6 volt (5 cell pack) would not last as long as the 4.8 volt pack. You have to make a judgement as to what you want... speed and torque... and make adjustments in the size pack. The trade off here is torque using a 6 volt pack, which will eat more wattage (meaning more current x voltage) than a 4.8 volt pack so if you do go to 6 volts, you have to increase the amp-hour rating (mil-amp rating) of your pack.

The OP said the pack size was, what.. 2650 mah? Heck, that will last for a good number of flighgts no matter if it's 4.8 or 6 volts.

CGr.