Anyone experienced a Bafang/Ultra mid-drive suddenly engaging FULL power regardless of PAS setting?

Tom@WashDC

Well-Known Member
Region
USA
City
Loudoun County, VA.
Last week I was riding around the lip/edge of a skate board park bowl, about 10" from the lip when suddenly my Bafang Ultra mid-drive lurched into full power driving me right over the edge head first into the concrete bowl. It happened so fast I did not hit my brakes until my front wheel was headed downwards into the bowl. I summersaulted crashing onto the floor with my bike on top of me. As my front wheel went over the edge, my last thoughts were: "Wtf?, why is this happening?, and it's got to be be at least 10-12 feet from my head onto that concrete floor, this is gonna be my worst fall ever".

Miraculously I was fine, a few scrapes on my elbows and knees, no helmet damage or scrapes. I remember rolling onto my back. I got up on my hands and knees, felt dizzy, and threw up, but I think it was just the adrenalin rush, the fear, and the disorienting flip over. I was very scared going into that fall. I don't remember much, except that I was very happy that I did not hear any bones crack.

I got back on my bike and as soon as I touched the pedal the motor engaged at Full+ power. It seemed like instantaneous power at a level I've never felt before, like it was a rocket. The torque sensor responded the same in all 5 PAS levels, instant massive power. I was able to eliminate the problem by cycling the power on and off. It has not happened since. I unplugged the throttle to isolate that variable. .

Recap: Has anyone ever experienced the Bafang mid-drive suddenly engaging at full+++ power regardless of PAS setting?

Just curious.
 
I haven’t experienced that myself, but full power regardless of the PAS setting sounds like a controller or torque sensor issue worth investigating. The fact that power cycling temporarily fixed it makes me wonder if the controller had a glitch.
 
Holly s*it! Glad you're ok!
I think you were prudent to eliminate the throttle to start. Could be that, wiring or as mentioned the controller. Don't think it would be the torque sensor as full output should still be regulated by the controller PAS setting.
I hope you have the brake cut_outs connected... not that they'll save you in every malfunction scenario but I see no downside to implementing them.
 
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