fractal said:
Hi guys, I found these specs on the official Greyborg thread. It was tested on 48 volts. They were posted by Markobetti, one of the developpers of the motor. Can anyone elaborate on this data? I have very limited knowledge on data like this and would like to learn. Thanks!
I used this chart and played with the ebikecalc17 program to try and model it with a 21.5" diameter tire. I'm not sure how accurate this model is, but at the different voltage vs output my model is within 5% of the output power when modeling different loads at 47-48V based on that chart so I'm guessing it should be pretty close. I'm setting the amp rate for the controller at 200A so I can find the BEMF point.
These are loaded speeds with the aerodynamics of a mountain bike with full weight bike + rider at a total of 270lbs
21.5" diameter tire
50V I get 27mph @ 23A
75V I get 40mph @ 40A
100V I get 53mph @ 61A
125V I get 64mph @ 86A
Those numbers seem pretty reasonable to me, but I won't find out until I get it installed this week and try it myself. I was told this motor is good for 24 and 26" wheels so I'm hoping my amp number are on the high side, just not sure if most will have enough amps to get into the BEMF point.
26" tire diameter I'm getting these numbers from my sim
50V I get 31mph @ 33A
75V I get 46mph @ 58A
100V I get 60mph @ 91A
125V I get 72mph @ 128A
Motor looks like a hell of a climber too when I start adding grade up to 10%. Waste heat doesn't goes up, but not sky high.
Examples at 100V 10% grade for 21.5" tire and 26" tires
21.5" tire
0% grade = 53mph @ 61A, 703 watts waste heat
10% grade = 50mph @ 87A, 1206 watts waste heat
26" tire
0% grade = 60mph @ 91A, 1274 watts waste heat
10% grade = 56mph @ 119A, 2044 watts waste heat
Going to be interesting to see how close my model is.