Titanium Fatbike - Bafang Ultra and Phaserunner


1 µW
Apr 14, 2021
Wow. Clean.... I'm impressed you got the phaserunner to fit in the motor case, but, are you not concerned with it potentially overheating in there ? I was considering attempting the same on a future build, but the phaserunners performance is seriously restricted when it can't be cooled...?


1 kW
Dec 6, 2019
Nice build!

You should try out the electronic freewheel feature in the paserunner suite. It keeps the motor engaged all the time and the responce and smoothness is awesome. Its sort of what you did with the throttle, but it is not active when the motor is stalled. Also much more adjustable (you should aim for having the motor spinning at the same speed as your driveline while coasting. Makes the responce from PAS really great). It burns a little watts, but it is what I love most about the controller, really! Mid drive systems gets so smooth with this engaged.

I dont have the same motor as you, but I did experience the same juddering on take-off and gear change. I had to lower the current regulator bandwidth agaist some of the advices I have seen, and then raise the PLL bandwidth to keep the over-current problems away. I ended up wit setting current bandwith to 0 and setting kp and ki manually in the end. Think it was kp=0.5 and ki=70. You have a different motor, so probably wont work with same numbers, but that was the way I made it at last. Lots of trying and failing on the way :p Just hang your rear wheel in the air and simulate with throttle and brake with the computer connected so it is fast and easy to test.