that's good news. Mine just started doing the same Exact thing! I bought a new kit to install on my Kona Stinky and was just getting ready to hit the track after my last test run when this happened. I'll check my Battery connections and cable. weird electric bugs.teslanv wrote:LeGrand suggested I check the battery connection. Turns out I had a poor connection somewhere in the line. Wired up a new battery cable and the controller is working like it should. No problem with the controller after all.teslanv wrote:I think my controller just crapped out.![]()
When I turn it on it flashes momentarily and then shuts down.
I have contacted both Paul and LeGrand about getting a replacement. Hoping I can get the new 9FET controller.
Less than 1000 miles on this unit.
I love this drive when it works, but Bafang better step up their game.
Bafang BBSxx - fault finding and fixes
- Somebodystopme!! 10 W
- Posts: 72
- Joined: Dec 25 2013 12:39am
Re: Bafang BBSxx - fault finding and fixes
- Somebodystopme!! 10 W
- Posts: 72
- Joined: Dec 25 2013 12:39am
Re: Bafang BBSxx - fault finding and fixes
That fixed it, thanks Tesla!
Re: Bafang BBSxx - fault finding and fixes
I too have experienced occasional chain drop on my BBS02, particularly following a rough section or when coming off a jump. I plan to transition to a new short cage Shimano Shadow+ derailleur with the clutch that maintains constant tension on the cage. I could also stand to shorten the chain by a couple of links. I may also add a chain guide up front as well. I'll report if this all amounts to fewer chain drops.I've now changed to a new cassette and chain. It all almost work fine.
The front chain sometime fell off while riding. It happens most of the time when I change gears.
Would that be because the chain isn't properly tensioned?
Or maybe i need some front chain alignment guide?
- Somebodystopme!! 10 W
- Posts: 72
- Joined: Dec 25 2013 12:39am
Re: Bafang BBSxx - fault finding and fixes
A chain guide upfront on the sprocket will or should, end those issues for you. They did for me.joshseitz wrote:I too have experienced occasional chain drop on my BBS02, particularly following a rough section or when coming off a jump. I plan to transition to a new short cage Shimano Shadow+ derailleur with the clutch that maintains constant tension on the cage. I could also stand to shorten the chain by a couple of links. I may also add a chain guide up front as well. I'll report if this all amounts to fewer chain drops.I've now changed to a new cassette and chain. It all almost work fine.
The front chain sometime fell off while riding. It happens most of the time when I change gears.
Would that be because the chain isn't properly tensioned?
Or maybe i need some front chain alignment guide?
Re: Bafang BBSxx - fault finding and fixes
I am in the process of transferring the motor from one bike to a new one. I have installed the motor and started wiring up it but have struck a problem similar to what teslanv previously reported in this video ...
Re: Bafang BBSxx - fault finding and fixes
I'm sick of pedal assist that never do it the way I want.
Is it possible to turn off pedal assist and only have throttle?
Is it possible to turn off pedal assist and only have throttle?
Re: Bafang BBSxx - fault finding and fixes
Don't pedal. OR. Turn assist to zero and use the throttle. Mine came programmed to run on throttle.cwah wrote:I'm sick of pedal assist that never do it the way I want.
Is it possible to turn off pedal assist and only have throttle?
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.
Re: Bafang BBSxx - fault finding and fixes
When i turn pedal assist to 0 the throttle stops too. In mine throttle is proportional to the level of pedal assist.tomjasz wrote:Don't pedal. OR. Turn assist to zero and use the throttle. Mine came programmed to run on throttle.cwah wrote:I'm sick of pedal assist that never do it the way I want.
Is it possible to turn off pedal assist and only have throttle?
I have C963
Re: Bafang BBSxx - fault finding and fixes
I'd go to the programming thread and find out what you can change. Sorry, I'm all set up to program but never bothered to change anything since I'm happy with the settings as they are. Someone will give you the answer. Lectric Cycles and EM3ev both ship with full throttle in all settings.cwah wrote:When i turn pedal assist to 0 the throttle stops too. In mine throttle is proportional to the level of pedal assist.tomjasz wrote:Don't pedal. OR. Turn assist to zero and use the throttle. Mine came programmed to run on throttle.cwah wrote:I'm sick of pedal assist that never do it the way I want.
Is it possible to turn off pedal assist and only have throttle?
I have C963
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.
Re: Bafang BBSxx - fault finding and fixes
Installed 2 BSS02 750w purchased 11/11 with 48v bottle batteries.
The one on my 29in mtb works very nicely. I haven't changed the programming as I have not received the USB to Serial connector yet. SWMBO said my grin was huge when I got back from my first ride.
Of course the 2nd unit, after installation on my SWMBO's bike yesterday, did not work as expected.
After installation and making the battery connections, and lots of zip ties, I pushed the power button to get into the password protected area and the rear wheel immediately spun, very disconcerting. The display stayed blank. I then, foolishly I think now, took the bike out and rode it up and down the block. Pedal assist was evident.
I turned be battery off and on a couple of times hoping there would be something to see on the display, no joy.
Today nothing happens when I pedal.
I haven't seen the behavior described in any of the bafang threads.
The battery checked out at 54v.
I have asked the Aliexpress vendor if I can swap displays between the two; but, I'm not sure what the problem is so I want them to say 'go ahead' as I'm guessing the 2nd controller might be able to fry the good display.
When told of the problem my son said "you haven't given feedback to them, right?". I had to say I have...
Oh, and before we get into the 'full support from trusted vendor' discussion I found this site on 11/11 and hadn't read the bafang and battery threads. I have read some/many of them now; but, there are a whole lot of pages in some of them!
I'll give updates to my progress when I can...
I guess right now I should mount the bottle batteries on both sides of my rear rack so they look like power nacelles!
The one on my 29in mtb works very nicely. I haven't changed the programming as I have not received the USB to Serial connector yet. SWMBO said my grin was huge when I got back from my first ride.
Of course the 2nd unit, after installation on my SWMBO's bike yesterday, did not work as expected.
After installation and making the battery connections, and lots of zip ties, I pushed the power button to get into the password protected area and the rear wheel immediately spun, very disconcerting. The display stayed blank. I then, foolishly I think now, took the bike out and rode it up and down the block. Pedal assist was evident.
I turned be battery off and on a couple of times hoping there would be something to see on the display, no joy.
Today nothing happens when I pedal.
I haven't seen the behavior described in any of the bafang threads.
The battery checked out at 54v.
I have asked the Aliexpress vendor if I can swap displays between the two; but, I'm not sure what the problem is so I want them to say 'go ahead' as I'm guessing the 2nd controller might be able to fry the good display.
When told of the problem my son said "you haven't given feedback to them, right?". I had to say I have...

Oh, and before we get into the 'full support from trusted vendor' discussion I found this site on 11/11 and hadn't read the bafang and battery threads. I have read some/many of them now; but, there are a whole lot of pages in some of them!
I'll give updates to my progress when I can...
I guess right now I should mount the bottle batteries on both sides of my rear rack so they look like power nacelles!

Re: Bafang BBSxx - fault finding and fixes
Hi Everyone,
I have a problem with my Bafang 250w kit with the C961 display.
The power comes and goes without any error message in the display. It worked fine for a couple of weeks before suddenly the power was gone and I got an error code 07 which is said to be over voltage protection. Then the power came and went for a while until it was permanently gone. After a week it started to work again. Now it mostly works but it happens that the power is lost for a while, but there isn't any error codes in the display.
I have tried with another battery so I have ruled out the battery. Any other that have similar problems? Could it be the wiring to the battery? I haven’t connected the brakes, could that lead to this?
Thanks
I have a problem with my Bafang 250w kit with the C961 display.
The power comes and goes without any error message in the display. It worked fine for a couple of weeks before suddenly the power was gone and I got an error code 07 which is said to be over voltage protection. Then the power came and went for a while until it was permanently gone. After a week it started to work again. Now it mostly works but it happens that the power is lost for a while, but there isn't any error codes in the display.
I have tried with another battery so I have ruled out the battery. Any other that have similar problems? Could it be the wiring to the battery? I haven’t connected the brakes, could that lead to this?
Thanks
Bafang Mid Drive BBS01 36V 250w 1408067115
- KINNINVIEKID 1 kW
- Posts: 353
- Joined: Jul 14 2014 4:49pm
- Location: Teesdale,England
Re: Bafang BBSxx - fault finding and fixes
Doesn't matter about the brake wires not being used.
Sounds like a problem in your wiring.
Time to get the multimeter out...
Sounds like a problem in your wiring.
Time to get the multimeter out...
BBSHD on 2017 Marin Muirwoods
BBS02 on Cannondale Trail 6
Dillenger 1000 watt front wheel kit on Trax TFS1 MTB.
250 watt chinese scooter!
Cyclamatic Power Plus 250 watt road bike.
BBS02 on Cannondale Trail 6
Dillenger 1000 watt front wheel kit on Trax TFS1 MTB.
250 watt chinese scooter!
Cyclamatic Power Plus 250 watt road bike.
Re: Bafang BBSxx - fault finding and fixes
7 could be motor hall sensor with the C961, by my version of the manual.brakestad wrote:Hi Everyone,
I have a problem with my Bafang 250w kit with the C961 display.
The power comes and goes without any error message in the display. It worked fine for a couple of weeks before suddenly the power was gone and I got an error code 07 which is said to be over voltage protection. Then the power came and went for a while until it was permanently gone. After a week it started to work again. Now it mostly works but it happens that the power is lost for a while, but there isn't any error codes in the display.
I have tried with another battery so I have ruled out the battery. Any other that have similar problems? Could it be the wiring to the battery? I haven’t connected the brakes, could that lead to this?
Thanks
http://endless-sphere.com/forums/viewto ... de#p958989
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.
Re: Bafang BBSxx - fault finding and fixes
Thanks for the input.
In my case the throttle doesn't work either when it stops, so then I assume it can’t be the motor hall sensor. Or is that a wrong assumption?
To investigate the wiring I guess I need to wait until it doesn't work? Or can can I get some information from a working system as well.
Some additional information:
Type: BBS01 36V 250w 1408067115
When the power is gone everything looks normal on the display, battery full, no error codes etc. The throttle doesn’t work either.
In my case the throttle doesn't work either when it stops, so then I assume it can’t be the motor hall sensor. Or is that a wrong assumption?
To investigate the wiring I guess I need to wait until it doesn't work? Or can can I get some information from a working system as well.
Some additional information:
Type: BBS01 36V 250w 1408067115
When the power is gone everything looks normal on the display, battery full, no error codes etc. The throttle doesn’t work either.
Bafang Mid Drive BBS01 36V 250w 1408067115
Re: Bafang BBSxx - fault finding and fixes
Based on my own experiences and what I learnt so far, I would:Mark-az wrote:Of course the 2nd unit, after installation on my SWMBO's bike yesterday, did not work as expected.
After installation and making the battery connections, and lots of zip ties, I pushed the power button to get into the password protected area and the rear wheel immediately spun, very disconcerting. The display stayed blank. I then, foolishly I think now, took the bike out and rode it up and down the block. Pedal assist was evident.
I turned be battery off and on a couple of times hoping there would be something to see on the display, no joy.
Today nothing happens when I pedal.
(1) Check any fuses at the battery level;
(2) Check the output voltage from the battery. If okay
(3) Check each connection for correct voltage on the input side AND the output side.
I suspect you have either a blown fuse or a voltage drop at one of your connectors.
Andrew
Re: Bafang BBSxx - fault finding and fixes
I'm getting the Err 21 on my display (BBS02, 750W), which is according to the manual, is a "speed sensor abnormality". The motor still works, just doesn't show speed and can't change the PAS setting once on the move. This was becoming annoying, so I do the following to remedy:
1. Check to make sure the sensor hasn't moved, and even moved it closer to the magnet on the rim. (still get err 21)
2. Check to make sure the magnet isn't de-magnetized - unlikely, but check anyway. (still get err)
3. Get a replacement sensor, wait forever and pay arm-and-leg for shipping, install it. (still get err)
4. Unclip the sensor wire from the bike frame (was zip-tied on) to check for damage to the wires that could cause shorting. Found nothing.
However.... I did discover that the motor had worked it's way loose in the BB, and was swivelling 10-15 degrees. This was putting strain on the three wires coming out of the main motor housing (battery, control, speed sensor). So now I'm thinking the sensor wires have been pulled out of the controller. I remove the motor, unscrew the cover, and find everything is covered in grey silicone. Can't see anything without removing it, and might cause more problems in the process.
Before I start digging around in the silicone covered controller, has anyone had a similar experience? Is there another likely problem? I might try cutting the existing sensor wires at the motor and try some new ones to see if the wires are the issue.
1. Check to make sure the sensor hasn't moved, and even moved it closer to the magnet on the rim. (still get err 21)
2. Check to make sure the magnet isn't de-magnetized - unlikely, but check anyway. (still get err)
3. Get a replacement sensor, wait forever and pay arm-and-leg for shipping, install it. (still get err)
4. Unclip the sensor wire from the bike frame (was zip-tied on) to check for damage to the wires that could cause shorting. Found nothing.
However.... I did discover that the motor had worked it's way loose in the BB, and was swivelling 10-15 degrees. This was putting strain on the three wires coming out of the main motor housing (battery, control, speed sensor). So now I'm thinking the sensor wires have been pulled out of the controller. I remove the motor, unscrew the cover, and find everything is covered in grey silicone. Can't see anything without removing it, and might cause more problems in the process.
Before I start digging around in the silicone covered controller, has anyone had a similar experience? Is there another likely problem? I might try cutting the existing sensor wires at the motor and try some new ones to see if the wires are the issue.
- mushymelon 1 kW
- Posts: 300
- Joined: Mar 28 2010 3:46am
- Location: Southern Ontario, Canada
Re: Bafang BBSxx - fault finding and fixes
Use a multimeter and check continuity between the pas sensor plug inside the motor and at the wheel first.CdnE90 wrote: Before I start digging around in the silicone covered controller, has anyone had a similar experience? Is there another likely problem? I might try cutting the existing sensor wires at the motor and try some new ones to see if the wires are the issue.
Re: Bafang BBSxx - fault finding and fixes
Which is the pas sensor plug?
Re: Bafang BBSxx - fault finding and fixes
You could have a look at this thread. He tracked down an error 21 issue.
http://endless-sphere.com/forums/viewto ... 28&t=65281
http://endless-sphere.com/forums/viewto ... 28&t=65281
Ian. LabTech for Plant and Marine stuff in Perth W.A.
Bafang 500W/48v on old Apollo MTB.
Bafang 500W/48v on old Apollo MTB.
- mushymelon 1 kW
- Posts: 300
- Joined: Mar 28 2010 3:46am
- Location: Southern Ontario, Canada
Re: Bafang BBSxx - fault finding and fixes
This oneCdnE90 wrote:Which is the pas sensor plug?
Re: Bafang BBSxx - fault finding and fixes
So... update.
I checked continuity between the plug and the wheel sensor. Nothing. So, at this point, it's either the wire has a break in it, or the wire is disconnected from the controller card. I cut the wire a couple of inches from the main motor body (what do I have to lose?) and checked continuity. All good, no breaks. That means there is something broken between the PAS plug and wheel sensor wire.
I take the controller off, and the black wire within the wheel sensor wire bundle slides out freely in my hand. Well, at least I know what the problem is. I dig down through the potting to discover both the red and black are disconnected (can't guarantee that I didn't pull the red off in my digging). Anyway, now I'm stuck trying to figure out which wire goes where. I've attached a zoomed-in picture here. You can see the white wire is still attached, and I think the black wire goes to ground and the red wire goes to the (+) marked spot.

I checked continuity between the plug and the wheel sensor. Nothing. So, at this point, it's either the wire has a break in it, or the wire is disconnected from the controller card. I cut the wire a couple of inches from the main motor body (what do I have to lose?) and checked continuity. All good, no breaks. That means there is something broken between the PAS plug and wheel sensor wire.
I take the controller off, and the black wire within the wheel sensor wire bundle slides out freely in my hand. Well, at least I know what the problem is. I dig down through the potting to discover both the red and black are disconnected (can't guarantee that I didn't pull the red off in my digging). Anyway, now I'm stuck trying to figure out which wire goes where. I've attached a zoomed-in picture here. You can see the white wire is still attached, and I think the black wire goes to ground and the red wire goes to the (+) marked spot.

- mushymelon 1 kW
- Posts: 300
- Joined: Mar 28 2010 3:46am
- Location: Southern Ontario, Canada
Re: Bafang BBSxx - fault finding and fixes
I have a bare controller ill go take some pics
brb
brb
- mushymelon 1 kW
- Posts: 300
- Joined: Mar 28 2010 3:46am
- Location: Southern Ontario, Canada
Re: Bafang BBSxx - fault finding and fixes
looks like I have a diffent board 9fet 750w
wiring is probably the same.
wiring is probably the same.
Re: Bafang BBSxx - fault finding and fixes
Some pics of an unpotted controller on this thread that may be of use??
http://endless-sphere.com/forums/viewto ... =2&t=62983
http://endless-sphere.com/forums/viewto ... =2&t=62983
Ian. LabTech for Plant and Marine stuff in Perth W.A.
Bafang 500W/48v on old Apollo MTB.
Bafang 500W/48v on old Apollo MTB.
- Arvicola Terrestris 100 W
- Posts: 109
- Joined: Apr 26 2014 5:01pm
- Location: Copenhagen - Denmark
Re: Bafang BBSxx - fault finding and fixes
I have made a separate thread about the bottom bracket and crank on the BBSxx, if anybody has found a repair kit i would like to know more about it.pompeimtb wrote:hi
crankset broken in my bafang... where i can buy pars crank Right and left?
Everybody is welcome to the thread, especially if you have good knowledge about Thrust ball bearings, which we right now are trying to identify.
http://endless-sphere.com/forums/viewto ... 28&t=65711
/philip
Christiania cargo trike, Bafang bbs02 750W, 48v, 16s2p LiFePO4 30Ah, 50kg
Grace mxII Urban S, 2. gen. Bosch 350W, 36v, Bosch Powerpack 400 11Ah, 23kg
Trek T420+, BionX PL250 HT, 250W, SRAM 3 speed IGH, 36v LiMn 9,6Ah, 20kg
U.S. Costomary Unit = SI Equivalent:
Length: in. = 25.40mm - ft = 0.3048m - mi = 1.609km
Mass: oz = 28.35g - lb = 0.4536kg
Pressure: psi = 6.895kPa (MPa = N/mm^2)
Velocity: mph = 1.609km/h
Volume: gal = 3.785l
Grace mxII Urban S, 2. gen. Bosch 350W, 36v, Bosch Powerpack 400 11Ah, 23kg
Trek T420+, BionX PL250 HT, 250W, SRAM 3 speed IGH, 36v LiMn 9,6Ah, 20kg
U.S. Costomary Unit = SI Equivalent:
Length: in. = 25.40mm - ft = 0.3048m - mi = 1.609km
Mass: oz = 28.35g - lb = 0.4536kg
Pressure: psi = 6.895kPa (MPa = N/mm^2)
Velocity: mph = 1.609km/h
Volume: gal = 3.785l