I almost lost an airplane running six digital servos with a lighter 1100 mah battery.

Although the battery looked good on the Voltwatch and read fine on the voltmeter the inflight load was another thing. My airplane went into lockout during some acro maneuvers, but regained signal as soon as the servo load lightened. If the voltage dips down under load to 4.7 volts it goes into lockout. I thankfully got the bird back on the ground safely.

I have since switched to a 6 volt 2500 mah battery which eliminates the problem. I now won't fly more than four digital servos on a 1100mah 4.8 volt due to the higher drain.