Motor velocity constant calculation in hubmotors


Looking at this spreadsheet document for motors, I was wondering how the kv was calculated for the hoverboard Hub-motor. This webpage explains different methods but in most of the methods, except one, involves the use of an electric drill. I believe the use of an electric drill in a hub-motor is not possible. Then, which method should I use? the KV / RPM meter?


You could probably estimate it quite easily using the ODrive in CTRL_MODE_VOLTAGE_CONTROL if you have an RPM meter…?

But beware that any method which drives the motor electrically (rather than mechanically, e.g. with an external motor such as an electric drill), will be driving at least some parasitic load from the motor’s iron core losses and bearing friction, in addition to the back-EMF for that particular speed (which is the thing you are trying to measure). So it will overestimate the kV slightly.