VESC - meaning and relation of displayed Current, Voltage, Power?

[braunschweiger]

I am not asking to explain the canonical W=V*A.
When running my VESC in current control at certain setting then the VESC phone app shows Current=7A and battery Voltage=40V. Now I would expect the Power at 7A * 40V =280W. Albeit I see the displayed Power to vary around 150-200Watts. The exact value or range of values is hard to tell while riding but definitely below the 280W.

So I am asking, what is the meaning of the displayed Voltage, Current and Power?

• Voltage would be battery voltage?
• Current to be the current through a motor phase whilst in duty portion of a cycle?
• Power to be Voltage * (duty[ in %] * Current) going into the motor or being drawn on the battery side?

 

[mxlemming]

I am not asking to explain the canonical W=V*A.
When running my VESC in current control at certain setting then the VESC phone app shows Current=7A and battery Voltage=40V. Now I would expect the Power at 7A * 40V =280W. Albeit I see the displayed Power to vary around 150-200Watts. The exact value or range of values is hard to tell while riding but definitely below the 280W.

So I am asking, what is the meaning of the displayed Voltage, Current and Power?

• Voltage would be battery voltage?
• Current to be the current through a motor phase whilst in duty portion of a cycle?
• Power to be Voltage * (duty[ in %] * Current) going into the motor or being drawn on the battery side?

Motor current is constant. It's not "in duty portion".
VESC reports motor, or phase current.
Voltage yes it's battery voltage.
It can also report battery current.
There's no easy link between battery and phase current. It approximately scales with duty but that's not totally correct so don't expect the math to work out exactly.

 

[braunschweiger]

ok, got it.
And what would be the meaning of 'Power' in this context on the display?

 

[mxlemming]

ok, got it.
And what would be the meaning of 'Power' in this context on the display?

Power is conserved. It reports battery power, doesn't account for dead time loses, resistance losses, magnetic losses... So the shaft power will be lower.