||The E-flite Power Meter is an economical and convenient measuring device that can be used in the field or in the workshop. It comes without connectors so that you can add your own of the type you use in your aircraft. It plugs in between the battery pack and speed controller. When you run your motor it displays Amps, and you can press the red Mode button to toggle through Volts and Watts (it calculates the Watts by multiplying the amps and volts that it is reading). Plug the meter in line with your charger and battery pack and the meter will display capacity while either charging or discharging.
Two things to remember - first, it is invasive (plugs in the line) so it must affect the reading somewhat (must have some internal resistance). Secondly, it is reading power in to the motor - power out is subject to the efficiency of the motor - if you are taking in 340W, and the motor is operating at 80% efficiency, the power out will be 272W. Having said that - this meter is a very economical and convenient indication which will allow you to make comparisons and inform your decisions.
Displays current up to 120A
Displays voltage up to 50V
Displays power up to 6000W
Displays battery capacity up to 9.99 Ah
Consumes 0.1A of current while operating
Low Price: $89