I have a BBSHD and have had it working flawlessly for 3 years until about 4 months ago when for some unknown reason when I power up the bike the PAS defaults to "1" instead of the normal "0". Also when it is in this or any of the other PAS levels the motor no longer stops when I stop pedaling. My go around at this point is to change to the "0" setting after powering on and leaving it there, using the throttle and riding the bike like a motorcycle. Tolerable but I miss riding in PAS mode! Has anyone heard of such an issue before and maybe a fix?
BBSHD defaults to PAS 1 when powered on
- Thread starter mowabute1
- Start date
Best guess without looking thru the many BBSHD threads for similar issues is that there is a (PAS) sensor failure inside the BBSHD casing. Could be the sensor itself, or a connection issue.
Many connection issues are either wire damage at the exit/entrance to/from a casing or a connector, or water intrusion into contacts or wiring, so those are something to check.
Another possibility is random settings corruption; unfortunately semiconductors are vulnerable to this kind of thing from various sources. You could note down all your settings, then reset to factory defaults, and see if it changes the behavior. If it works correctly (for factory settings) then begin putting your own back in and retesting at each step to see if any specific setting changes behavior to incorrect operation.
It can also be firmware that has become corrupted; I don't know that there is a way to be sure of getting the correct / same firmware for your unit to reflash, and the wrong firmware can brick the controller. Even if it's correct for your controller version, it may change it's behavior from what you're used to. There are some threads with various firmwares in them, and discussion about them.
Many connection issues are either wire damage at the exit/entrance to/from a casing or a connector, or water intrusion into contacts or wiring, so those are something to check.
Another possibility is random settings corruption; unfortunately semiconductors are vulnerable to this kind of thing from various sources. You could note down all your settings, then reset to factory defaults, and see if it changes the behavior. If it works correctly (for factory settings) then begin putting your own back in and retesting at each step to see if any specific setting changes behavior to incorrect operation.
It can also be firmware that has become corrupted; I don't know that there is a way to be sure of getting the correct / same firmware for your unit to reflash, and the wrong firmware can brick the controller. Even if it's correct for your controller version, it may change it's behavior from what you're used to. There are some threads with various firmwares in them, and discussion about them.
tomjasz
1 GW
YouTube
4:17
How to replace Bafang BBS PAS Circuit Part I
YouTube · GreenBikeKit-Bafang motors and batteries services
4 minutes, 17 seconds
Dec 5, 2021
1:08
Bafang BBS motor PAS circuit replacement part II
YouTube · GreenBikeKit-Bafang motors and batteries services
1 minute, 8 seconds
Dec 10, 2021
4:17
How to replace Bafang BBS PAS Circuit Part I
YouTube · GreenBikeKit-Bafang motors and batteries services
4 minutes, 17 seconds
Dec 5, 2021
1:08
Bafang BBS motor PAS circuit replacement part II
YouTube · GreenBikeKit-Bafang motors and batteries services
1 minute, 8 seconds
Dec 10, 2021
Thanks for those links as they will be quite helpful if needed. In the video description it says "If your Bafang BBS motor has no resistance when pedaling or the motor cannot stop when using throttle, the PAS circuit would be defective.". My motor has resistance when pedaling and the motor stops when using the throttle, so those particular symptoms do not apply to my situation. I might add that I am able to progress through the PAS settings while riding, but the motor does not stop when I stop pedaling. I have been told by one major Bafang distributor that they were unfamiliar with such a problem and suggested I try replacing the controller. I suppose that is the easiest way to go, although not cheap, to see if that would fix the problem.tomjasz said:
Another symptom of how it behaves is that when it is in "0" PAS setting and I just use my throttle, I notice when I release the throttle the chainring continues to slowly turn. I'm not sure if the video description referenced above was referring to this when it stated "the motor cannot stop when using throttle". If I just pedal, no throttle, and then stop pedaling, again the chainring slowly continues turning. It continues to turn until I am almost, but not quite, at a full stop. So it stops turning at maybe 1mph or so. If I turn off the power at the display while riding at any speed the chainring stops and only turns when I am pedaling, as it should.
tomjasz
1 GW
IME the PAS PCB can do weird things, but perhaps the weakest point in the BBSxx series has always been the controllers. Although early BBSHD had weak rotor shafts as well. IMO all BBSxx owners do themselves a favor by having a backup controller. Just pay attention to the firmware version. Later builds are better. It seems BaFang is moving towards a proprietary system making having a few consumables for your BBSHD a wise investment.
Best of luck sorting.
Best of luck sorting.
Gremlin500
1 µW
- Joined
- May 8, 2021
- Messages
- 2
Isn’t that simply the default behaviour?
I have both BBSHD2 and BBSO2 and both boot up in PAS1.
I have both BBSHD2 and BBSO2 and both boot up in PAS1.
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