I connected it to my test circuit, which consists of an Arduino controlled buck converter driving two LEDs in series at 100% duty cycle. The series forward voltage of the two LEDs is about 5V so you can infer power from the current but I didn't actually measure Vf, which goes up modestly as current rises. The data was acquired on my motorized testing jig. I'm using the Arduino to log the current at different speeds. Speed is calculated using zero-cross detection to measure the frequency of the pulses coming from the hub. My jig has crappy speed control so all I can do is ramp it up and slow it down and catch the current at each speed. At each speed I collect the average current of two complete wheel rotations (again, as measured using hub pulse frequency) four times and plot the average of that. Error bars are standard deviation of the mean.
The hub seems to saturate around 750 mA, although my multimeter is reading 900
Decreasing the gap between the magnets and the claw poles of the armature might also help make the hub more efficient. At the moment they are about 0.050-0.060", whereas the original magnet is probably closer to 0.010-0.020".
Will post photos of the upgrade as soon as I have them!
Update: I found a photo of the adapter sticking to my fridge.
GH6 magnet adapter upgrade with Neodymium magnets in place |
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