I know a voltmeter would be good but i read that the battery stays at 4.8 volts for so long. How do i get an idea of how long itll stay at 4.8 volts before the voltages crashes. the charts make it seem that itll stay at 4.8 volts or higher for 80% of the batteries charge. So if i know the mah per flight, ill have an idea of how long i have left and when the 4.8 is gonna drop rapidly.

My real question is about 33mah per flight. Is that a reasonable number?