Wattage whats it all about?

[Brannenthompson1]

I have had a 36v 500w hub motor for a couple of months and love it and have now added a watt meter, The watt meter shows 750w max, 22amps x 36v so is this right as it seems quite fast I've seen 26mph on the flat no problem, So is there a problem and am I damaging anything?

 

[anotherkiwi]

On my calculator hot off the charger @ 42 V you should be seeing 924 W so something must be wrong!

With a motor like that the only thing you are going to damage is "serious" cyclists morale when you zip past them.

 

[Benjahmin]

The stated wattage of the motor is merely its continuous rating. That is the power it can take for one hour without overheating. The power it actually takes is determined by what the controller is putting out. So AK is right, 924w max hot of the charger. It's unlikely that you'll use this for very long 'cos if you do your battery ain't gonna take you very far. So motor will not be damaged. Ride it like you nicked it

 

[Deleted member 4366]

You're measuring the power from the battery, not the motor's output power, which will be much less.

The power from the battery is regulated tom 22 amps by the controller up to something like 50% of maximum speed, then the power is cut down by the back emf from the motor, so the wattmeter will show the power decreasing as you speed up past that point, until it reaches zero at the motor's maximum rpm. That's why there's a speed beyond which the motor won't go.

You'll see that you can only draw maximum power when accelerating from a start and grinding your way up hills. If you have a KT controller, you'll also see that there's a different current limit with each of the five PAS levels, which don't affect the throttle control.

 

[Brannenthompson1]

That's exactly what I noticed 22.5 amps and as speed increases, it drops off.
Thanks everyone