Originally Posted by Plantoflap
The rpm is not needed to find the efficiency, nor is the true kv because you know the Io amp draw and Rint.
E = Efficiency = Po/Pin Io=no load amps Rint= internal resistance, should include esc fet resistance since they are in series with the motor leads.
Pin=Vin* Ain Po=( Vin-(Ain*Rint)) * (Ain-Io)
E = ( ( 1- (sq root of (Io * Rint / Vin )) )^2
Amps at max power = ( Vin + (Rint*Io)) / (2*Rint)
Io increases with rpm, its a curve. when you get your new meter graph kv and Io at various rpm. Graph the calculated amps, power and efficiency too.
Thanks, but what I really need to know is how to get in real life the thrust predicted by the calculators.
Or, failing that, some ideas on where the difference comes from.