Math Error/ Telemetry

[Navherc130]

I reread an article in Vol 4 of RCBoat Mag re: motor upgrade for a motley. If I use a 1900 kv (1770W) motor with 4s..I should need something to handle 120A with a 10-20% buffer? 1770/14.8 = 119.5A correct? So to get the amp usage down, going 5s sound viable? 1770W/18.5 = 96Amps. Where does prop load come in with the AQ 42/55? What type of telemetry is being used out there to record actual draw? Thanks

[siberianhusky]

Motor watts and amps mean just about nothing, it is the prop that determines the load nothing else (given that the boat is set up properly).
Changing to 5s you will have to drop own in prop size or your amp draw will go up unless you choose a lower KV motor.
The formula for watts from amps and volts only works if you are comparing apples to apples. If you were to choose a motor with a lower kv that will allow you the same rpm as the 4s setup (26000) AND use the same prop ONLY then will amp the amp draw will go down.