spiked said:
Is this high temperature something we need to worry about?
Sure it is!! I hope you did read the wiki link I post that says:
The Curie temperature of high-grade Neodymium (with added terbium and dysprosium) is 320C / 600F. However, common neo magnets are made from the cheapest grade, and can start to lose some of their magnetism at around 80C (170F).
E-bike motor magnets are a grade that is slightly higher than the cheapest variety, because they are often subjected to higher temps than they should be by unsuspecting customers. Years of posted experiments by real E-bikers on endless-sphere have produced a commonly held rule-of-thumb to avoid heating your E-bike motor to above 95C (200F).
In: https://www.electricbike.com/motor-tech-learn-the-terms-part-1
spiked said:
Did you drive the motor really hard to get it this hot, or was this just a routine ride? What battery was used?
I did not ride hard and was a routine ride, I was at max of 500W (about 10 amps) at some peaks. As you can see on LCD, I used 61 Watts/hour is 15 minutes so at power average of 61 *4 = 244 watts (half of that max of 50W).
At 85 degrees of the motor, outside I could touch with my hand and see it was very hot but clearly I already did touch my motor from the outside more hot than that. It is easy, the same ride I did of 15 minutes, I usually do the same type of ride but for about 60 minutes - 4 times more!!
But I hope other users can replicate my experience and so we can get more data and validate all this.