Rix said:I never liked the idea of adding external small fans , because it just adds another electrical element that can get damaged.
Can you elaborate, I am not understanding what you mean with adding "another electrical element that can get damaged". Seems to me the fins, whether they got damaged or not, wouldn't affect the functionality of the motor.
Ive seen some people mount 1 or more electrical small cooling fans to the hub motor. Id rather use cooling holes to let the trapped hot air escape or air scoops fastened to the hub that deliver the moving air right over the hub motor or of course heat sink fins.
I'm currently running a 3k nominal hub motor, but it has been treated with ferro fluid and I can run it at 5000 watts, and it gets very warm, but not hot. I cut my phase wires to be as short as possible to the controller/ motor and upgraded from 10 gauge wire to 8 gauge wire. I think if I wanted to run the motor at 6000- 7000 watts, it could take it, but I would need to add either heat sink fins to the motor, or a air scoop to force the moving air over the hub. Ive tried cooling with auto trans fluid and did not like the results. I still think air cooling holes in the side covers is the best and easiest way for cooling, but I ride on many gravel roads and it is to dusty. I don't wanna risk getting the inside of the hub motor dirty.