I know a lot of people use unregulated LiFe batteries but I've also read about servo issues at max charge. Then again, I think I read the same thing about servos with a fully charged 6 cell nickle battery. No problem running a regulator if that's what you choose to do. I use (two) regulated lipos because it still comes out lighter in weight and I get consistent servo speed and power from the beginning to the end of the day.