You could check if the servo is moving the valve max in both directions. Or there can be internal leakage in cylinder, or valve, so it don't get enough pressure?
Thanks for the info on batteries, Cooper. Seeing all your batteries , I am certainly glad I just got 4 Lipo's and 2 models, and 1 for the transmitter to keep track of at once
About the 'common sence battery balancer'..doesn't most/all newer LiPo chargers have this function of balancing, built in?