I am also using the 2200 mah Life, it is very lightweight and I can do 6 flights with my Passport with all digital servos. At the end of the day it will take only around 1000 milliamps of charge . There is also a smaller capacity 1100 mAh pack and it only weights 85 grams versus 143 grams of the 2100 mAh. The Lipo and voltage regulator is also a good combination but personally I think that it is one more possible point of failure (the regulator).