Well, I got two Powerextra Batteries (6300mAh 14.8V 93.2Wh) and charged them up to the 16.8V, 4.2V each cell yesterday. Today, went to fly and put the new battery in and got 16.8v on the ST16, did my check list and then armed the motors and it dropped to 15.7V. I probably should have stopped there but I flew anyway. The volts kept dropping and after only 8 minutes of flight was at 14.6V. So I landed. Put a standard battery and flew my usually 18 minutes before 14.6V. Tried the second Powerextra battery with the same results. Anybody have any trouble with these batteries?