I'm imagining that once you have battery management systems, motor controllers and flight control systems then maintenance will become more like a continuous condition monitoring process by electronic means along with almost all preflight tasks. At least some of the high end UAVs are doing this at least partially and most of the big jet turbines are likewise under continuous surveillance.
Battery capacity will be determined every discharge-charge cycle.
Last edited by Andy_RR; 9th Jan 2019 at 11:34.