I have an ELF (with a mid-drive motor that goes to a rear freewheel). The motor is a XOFO DD45 and it runs off of a Grin BaseRunner v4 L10. Though I don't think it is relevant, there is also a second motor running on a separate controller, both running off of my CycleAnalyst v3. I recently pulled the motor out and reinstalled it - almost 100% sure I didn't do anything different from how it's always been (for years). It runs great and seemingly normally ... until I stop. When stopped, if the motor turns backward the slightest amount (such as if the vehicle rocks back on a hill at a stoplight), the motor will start to very slowly rotate in reverse with no throttle input.
By "slowly", I mean something 30 RPM. And, I can reach under there and stop the motor easily with one hand. When I do, it twitches a couple of times, then stops. It will sit motionless unless I turn it again ... even just like a degree.
It doesn't feel like it is actually trying to run in reverse. It feels more like it is doing some weird e-braking/regen thing. I don't have any real evidence for that, so take it for what it's worth. I have tried tweaking the braking and regen voltages to no avail. The input min/max voltages are the same as the other motor/controller which does not exhibit this same issue.
I think the best clue, here, is that if I turn off hall sensor start and run purely sensorless, the problem goes away. I would blame a hall sensor, but I tested each individually and can also see that they are firing in a logical order: Blue/Green -> Blue -> Blue/Yellow -> Yellow -> Yellow/Green -> Green -> Blue/Green.
In practice, this isn't really causing any problems. The motor runs like a champ and when it turns slowly in reverse, it really isn't hurting anything since it is on the freewheel. But, it makes me wonder if it is not a symptom of something I do need to pay attention to.
Any thoughts?
Cheers,
-B
By "slowly", I mean something 30 RPM. And, I can reach under there and stop the motor easily with one hand. When I do, it twitches a couple of times, then stops. It will sit motionless unless I turn it again ... even just like a degree.
It doesn't feel like it is actually trying to run in reverse. It feels more like it is doing some weird e-braking/regen thing. I don't have any real evidence for that, so take it for what it's worth. I have tried tweaking the braking and regen voltages to no avail. The input min/max voltages are the same as the other motor/controller which does not exhibit this same issue.
I think the best clue, here, is that if I turn off hall sensor start and run purely sensorless, the problem goes away. I would blame a hall sensor, but I tested each individually and can also see that they are firing in a logical order: Blue/Green -> Blue -> Blue/Yellow -> Yellow -> Yellow/Green -> Green -> Blue/Green.
In practice, this isn't really causing any problems. The motor runs like a champ and when it turns slowly in reverse, it really isn't hurting anything since it is on the freewheel. But, it makes me wonder if it is not a symptom of something I do need to pay attention to.
Any thoughts?
Cheers,
-B