E-bike build Overvolting dd hub motor

[j bjork]

To clarify, my results are based on how long I could ride before the windings got over 130 degrees C.
That is where I set my power rollback, and completely cut at 150 degrees C. So a ride often ended with a winding temp about 140 degrees.
With statoraid it was probably double the runtime or something, with just a little higher outside temp on the rotor.
I added hubsinks anyway, but the difference wasnt very noticeable in runtime from what I remember.
I suppose it probably made a difference in outside temp on the rotor, but I dont really remember how much.

 

[Pilip]

Certainly not. 80*C is not demagnetizing the hub.

I run well over 200* C peaks, and I certainly reach a stabilized temperature of 150*C +... on the winding sensor. No detriment to the magnetic flux from the motor.

In fact, here is the QS published magnet grade chart.. and they DO NOT lose magnetisim at 80*C as you quote...... they withsand double that, ( 160*C!) even at a 100% or greater duty cycle.

QS magnets are listed as SH35. I do not think I have seen anything near this high on the hubs I have tested.. on the magnet ring... yes I agree here. ....the magnet ring is very well cooled... but there is measurable heat transfer.

The higher the heat of a thermal transfer, the greater the efficincy. Wellknown factor of heat engine design. Also applies to elecrical motors.

Cool, I didn't know about that.

 

[E-HP]

Similar to batteries, use the general guidance and actual experiences to determine what you're comfortable with for your setup. I feel my 90C rollback and 120C cutoff is conservative, others may not, but the values shouldn't leave me stranded somewhere with a burnt motor (I hope). I've never hit cutoff, with maybe 110C max, but have experience rollback several times, which gives me time to find a good place to stop. When I open the motor to reapply Statorade, I'll have the opportunity to reassess when inspecting the windings. I'm hoping they look like shiny copper, like before the motor ever ran, and not smelly dark coffee looking from burnt enamel. Depending on what I find, I can adjust.