I have the same issue with the CastleCreations Pegasus 35P, the highest setting for voltage cutoff is 8.4v (2.7v per cell), which is too low for most of the 3 cell Lipo batteries we use, (except the $90 Nuke-proof packs). 9v is the recommend cutoff point for most of the common 3 cell Li-ion & Lipo batteries, 3v per cell. Anything lower results in swollen packs, won't charge, or dis-charges very rapidly. I just use a digital stopwatch zip-tied to my TX, when I reach 10-12 minutes, or I'm at 3/4 throttle, I stop flying.

Rick