Today it was sunny and about 20 deg.C / 68 deg.F ā perfect weather for motor-temperature testing!
To get the motor stressed I did run on grass, each time for 5 minutes with mostly full throttle ...
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... the only downside of this was that my 5400mAh packs did only last for 10 min. each!
However, here are the motor temperatures (measured with a thermocouple, so should be quite accurate):
Run #1/ No cooling (stock): 65 deg.C / 149 deg.F
Run #2/ Heatsink on motor with fan switched off: 57 deg.C / 134 deg.F
Run #3/ Heatsink on motor with fan switched on: 45 deg.C / 113 deg.F
Overall, I am satisfied ā the result from run #3 shows that the motor gets cooled down significantly and there should be also enough margin left for hot summer days as well.
With outside temperatures up to what it was today, I will probably only use the passive cooling by the added heatsink (by the way, this is comparable what I measured with the 30mm fan placed behind the motor) ⦠and when it gets warmer, the fan will be switched on.