Bafang BBSxx - fault finding and fixes

HI folks!

I am currently getting some high mechanical rattling sound from my BBS02 motor. The sound is worse during low motor load. It's a bit less during high load, but it does not sound good, and it is getting worse.

I have already opened up the motor and could not find any visible problem. I have included a video with the sound. Do you have any idea what the problem could be? I have btw already performed the loctite fix by fixing the rotor to the ball bearing with loctite. Maybe I need to change the ballbearing?

Btw, what is the best way of removing old grease from the gears?

https://photos.app.goo.gl/tACQsZnBJsbcsnL49

Thanks in advance!
 
Hello experts!

I've had BBSHD installed on Specialized Fuse 6fattie just over 2 years and it has been perfectly reliable, it hasn't failed at all even when i sometimes abuse it hardly.

It started some intermittent power cutting randomly couple weeks ago, after i washed the bike with hose (yes, stupid, i know), of course the battery was not installed.
There was a little water in power cable and after drying, worked again perfectly like 300 kilometers.
Couple days ago it started to work weirdly again.
First gearsensor started to work intermittently, i disconnected that and after couple kilometers PAS stopped working in 1 and 3, worked like step 1 when in 5. Throttle worked flawless all time.
I disconnected the battery and waited like 15mins, after that PAS worked again, until after like 10 kilometers it suddenly put 100% power with any PAS level. Again reboot, and worked rest of my ~25 kilometer trip.

After couple hours stand, bike worked again perfectly about 20km trip to my friend, we had couple hours fun evening and when i started to go home, bike worked badly like 150 meters giving intermittent power all time and died. I stopped and disconnected everything, leaving just Eggrider and throttle, motor still not running.
It started to "jerk" like 1/10 rotate of chainring every time i turned Eggrider on and no power to motor.
When i got home I tried DCP14 display and it did show Error 12H, after that whole system cuts off when i push throttle/pedal and battery shows red/green leds, it just "jerks" that small movement to chainring and dies. I can turn whole system on, but it dies instantly when pushing throttle/pedal.
Bike is also very, very jerky to push backwards, about 3-4 times harder than normally with BBSHD. Forward pedaling works normally.
That jerky resistance when pushing backwards is weird, there is no power/battery in bike so broken controller should not be involved to that.
Battery is ok, it works in my brothers BBSHD setup, but i think my motor/controller is broken..


And update:
This is going more mysterious.
I did disassemble whole system from bike to get it to table for closer inspection.
Every wire and connector seems perfect, no bents, burns, broken insulate, nothing.
I did tear down for motor and rotor, stator, every electronics, windings etc. looks like brand new, also nylon gear looks like it's not even used., no signs of water or rust anywhere.

System turns on, but still no life in motor, i tried also with brand new controller, 2 displays (eggrider v2 and DCP14), and with 2 throttles, mixing them together, still nothing.
New controller shows an error "30H No signal", old controller doesn't show any errors, both shows battery voltage right.
Now it doesn't die when throttle is pushed, it just don't do absolutely nothing, not even chainring "jerk", also no more red/green over current leds in batterypack.

I have no idea what is going on, i think i'll order new main harness, just to eliminate that fail option. If that doesn't help, i don't know what to do.
Any ideas?
 
Tofe said:
Hello experts!

I've had BBSHD installed on Specialized Fuse 6fattie just over 2 years and it has been perfectly reliable, it hasn't failed at all even when i sometimes abuse it hardly.

It started some intermittent power cutting randomly couple weeks ago, after i washed the bike with hose (yes, stupid, i know), of course the battery was not installed.
There was a little water in power cable and after drying, worked again perfectly like 300 kilometers.
Couple days ago it started to work weirdly again.
First gearsensor started to work intermittently, i disconnected that and after couple kilometers PAS stopped working in 1 and 3, worked like step 1 when in 5. Throttle worked flawless all time.
I disconnected the battery and waited like 15mins, after that PAS worked again, until after like 10 kilometers it suddenly put 100% power with any PAS level. Again reboot, and worked rest of my ~25 kilometer trip.

After couple hours stand, bike worked again perfectly about 20km trip to my friend, we had couple hours fun evening and when i started to go home, bike worked badly like 150 meters giving intermittent power all time and died. I stopped and disconnected everything, leaving just Eggrider and throttle, motor still not running.
It started to "jerk" like 1/10 rotate of chainring every time i turned Eggrider on and no power to motor.
When i got home I tried DCP14 display and it did show Error 12H, after that whole system cuts off when i push throttle/pedal and battery shows red/green leds, it just "jerks" that small movement to chainring and dies. I can turn whole system on, but it dies instantly when pushing throttle/pedal.
Bike is also very, very jerky to push backwards, about 3-4 times harder than normally with BBSHD. Forward pedaling works normally.
That jerky resistance when pushing backwards is weird, there is no power/battery in bike so broken controller should not be involved to that.
Battery is ok, it works in my brothers BBSHD setup, but i think my motor/controller is broken..


And update:
This is going more mysterious.
I did disassemble whole system from bike to get it to table for closer inspection.
Every wire and connector seems perfect, no bents, burns, broken insulate, nothing.
I did tear down for motor and rotor, stator, every electronics, windings etc. looks like brand new, also nylon gear looks like it's not even used., no signs of water or rust anywhere.

System turns on, but still no life in motor, i tried also with brand new controller, 2 displays (eggrider v2 and DCP14), and with 2 throttles, mixing them together, still nothing.
New controller shows an error "30H No signal", old controller doesn't show any errors, both shows battery voltage right.
Now it doesn't die when throttle is pushed, it just don't do absolutely nothing, not even chainring "jerk", also no more red/green over current leds in batterypack.

I have no idea what is going on, i think i'll order new main harness, just to eliminate that fail option. If that doesn't help, i don't know what to do.
Any ideas?

And update again.

I tested with brand new main harness, still nothing, just error 30H with new controller and no errors with old one, and still no life with neither.
But! I was just to start a motivation suicide with this unit, when House was completely silent, kids not yelling and wife not barking, and I pressed throttle when old controller was attached.
I heard very, very tiny "snap" or "tick" every time I pressed.
It comes from motor core, and actually I can feel it better than it sounds, when I keep motorcore in my hand. It also "snaps" when I turn display on.
So, I think motor core/stator is somehow faulty, that would explain jerkiness and overcurrent protection.
Now ill try to tear down stator from case and see how it looks like.

Maybe I'm near, I think?
 
If there was a short between windings it may be hard to find. One simple test is to just make sure there is no connection between the phase wires and the stator iron. If there is continuity, that's a bad sign. Even if there is no continuity, you could still get a short between wire turns. About the only other simple way to detect a shorted turn is to find a way to spin the motor and check for excessive resistance to turning. With everything assembled, power off, if you push the bike backward, the motor will spin. Normally there is some resistance due to the cogging but you can easily push the bike backward.
 
Update about my problem.

I took the advice of using one grease on the whole unit instead the black and white stuff, as explained by this site:
https://electricbike-blog.com/2015/12/23/mobilgrease-28-bbshdbbs02-because-a-good-mid-drive-is-better-seen-and-not-heard/

The motor sounds much better now. Tried for a little ride and it much more smooth as well. Seems to get more power also.
https://photos.app.goo.gl/kKFZ8a2ehEXW9P8f6

However, it's maybe not super smooth as it was when it was new. There were still some black spots on the nylon gear. Difficult to get it 100% clean. So it may be a bit damaged from the black grease that has leaked inside.


staldor said:
HI folks!

I am currently getting some high mechanical rattling sound from my BBS02 motor. The sound is worse during low motor load. It's a bit less during high load, but it does not sound good, and it is getting worse.

I have already opened up the motor and could not find any visible problem. I have included a video with the sound. Do you have any idea what the problem could be? I have btw already performed the loctite fix by fixing the rotor to the ball bearing with loctite. Maybe I need to change the ballbearing?

Btw, what is the best way of removing old grease from the gears?

https://photos.app.goo.gl/tACQsZnBJsbcsnL49

Thanks in advance!
 
The green Yago (might be wrong with the name) attaching my C965 display to the BBS02B harness has become intermittent.
By very hot weather, above 30C, when I turn the C965 on, the display turns on for 1 second, then turns back off. Impossible to turn it on.

Plugging and unplugging the green connector or partly inserting it seems to temporarily solve the issue.

Once at home, I cleaned the connector contacts with 90% isopropanol and inserted/removed a few times the male part into its female counterpart.

I don't think it's a permanent solution though. Future will tell. I keep a display bypass wire to connect to the motor in case of emergency: I don't like the idea to get back home on my own power. I build it from a defunct C965 which I kept the cable of and shorted 2 wires to get power to the motor. It does the job but at MAX PAS, so I use the throttle to overrule the PAS.

Maybe a 5 connector replacement fitting could do the job, or direct soldered connection between each wire, bypassing the green connector and trashing it.

Does ayone had a better idea? Or a suitable replacement connector to suggest?
 
My BBS02 (750W, 48V) stopped working.
The display is dead, the engine is not running.
No reaction to the connection of the programming cable to activate the drive with the lever, or by turning the pedals.
When I connected a second functional battery, nothing changed.

I removed the controller, measured:
- between the minus and the phases is 6.74 6.97 and 7.65 k ohms.
- between the plus and the phases there are about 290 570 and 220 kilohms.

In addition, on one of the pins in the display connector there is no full 52V battery voltage, only about 22V is there.

Please help me fix the drive.
 
Hello fellow ebikers,

I am an avid cyclist from germany and thanks to lurking on endless sphere for a long time build several bbs02 bikes too. All 3 motors are very fun, and so far reliable (around 3000kms each)

1 week ago i build a new bike, a recumbent with rohloff, today was its first launch.
After 30 Kilometers of light driving this happened- Suddenly the bike went noisy and jerky, and after short inspection, i found this misery:

The pinion gear "drilled" a hole in the housing, came out, and hit the chainring! Too bad i was in a hilly forrest 15 km from home in heavy rain. I had to knock the pinion inside again with a stone every 300 meters or so )-;

Anyone experienced similar?

Of course i didnt fiddle with the unit, its new from psw power, and ran only 30 km.

Did the forgot the Snap Ring maybe? IMG_20210816_173500.jpg
 
Wow! I’ve never seen that happen before.
It will make it easy to lube :wink:
There must be snap ring missing like you say. I’m not exactly sure what holds that part in place. It should be pretty obvious when you take it apart.
 
Looks funny, right? Either forgotten or broken snapring, because cheap material. Cant wait to open it up and see what caused it, might be interesting anyway, and nice opportunity to do the grease, but, - of course first option is to let the supplier (psw power) take care of it. Will let you know about the outcome.
 
revain said:
I removed the controller, measured:
- between the minus and the phases is 6.74 6.97 and 7.65 k ohms.
- between the plus and the phases there are about 290 570 and 220 kilohms.

In addition, on one of the pins in the display connector there is no full 52V battery voltage, only about 22V is there.

Please help me fix the drive.
The resistance measurements look normal.
The brown wire going to the display should have full pack voltage. Double check you have full pack voltage on the main battery wires. If so then you’ll have to open the controller and see where the voltage stops. I’d try re-seating the connection on the controller board that goes to the display first.
 
Chaitaichai said:
Hello fellow ebikers,

I am an avid cyclist from germany and thanks to lurking on endless sphere for a long time build several bbs02 bikes too. All 3 motors are very fun, and so far reliable (around 3000kms each)

1 week ago i build a new bike, a recumbent with rohloff, today was its first launch.
After 30 Kilometers of light driving this happened- Suddenly the bike went noisy and jerky, and after short inspection, i found this misery:

The pinion gear "drilled" a hole in the housing, came out, and hit the chainring! Too bad i was in a hilly forrest 15 km from home in heavy rain. I had to knock the pinion inside again with a stone every 300 meters or so )-;

Anyone experienced similar?

Of course i didnt fiddle with the unit, its new from psw power, and ran only 30 km.

Did the forgot the Snap Ring maybe? IMG_20210816_173500.jpg

So what caused the Problem? Loose snapring?On first sight this was exactly the case, upper snapring was loose but not broken. White Plastic gear came out without pliers. But next thing i saw was really weird, the bearing from the pinion gear ALSO came out with the pinion. This means the other snapring is tight and the pinion COULDNT have left its track and grind on the housing! Its very mysterious. Maybe the snaprings where bad quality (not enough tension?)and come on and off spontaniously?


I bought snapring pliers and new snaprings, and mounted everything together, which after some tutorials wasnt too hard, and did multiple trips successful. Also gained some knownledge for the structure of this great little engines.
I ordered mobilith shc 100, and will glue the hole in the cover afterwards, in the hopes to have it futurproof now.

So about psw power, the seller, -how did they behave?I was in contact with Alice Luo and got two options, either to do the repair myself with spareparts shipped for free. Or second option send it over to a german repairshop.
As i had the feeling the repair will be doable and faster than all the shipping stuff, i choose to do it myself and asked for a partial of 60€ refund which was agreed upon.

The communication response was rather "economic" and could be improved, but nonetheless i am satisfied with the outcome.
The reason for loose snaprings are unknown, but i guess this will not happen often, so simply bad luck.
This wasnt psw powers fault, but bafangs, so i think it was handled adequately.

I can definitely recommend psw power as a supplier for bafang motors in germany.
 

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My BBS02 36V 500W controller died :( so am trying to replace the mosfets. Whilst removing the potting material, I might have accidentally damaged an inductor. It is circled in red in the photo.
Does anyone know what value this is to replace it with?
BBS02 controller (1).jpg

Also how do you remove the mosfet heatsink screw that is behind the large capacity as there is no room for a screwdriver. I thought of trying to unsolder the capacitor but is not obvious where the legs are soldered underneath the board. See photo.capacitor solder points (1).jpg
 
I’d get a new controller. Unless it’s a pre 2016 and there are none available. Bafang is moving towards a Bosch like system and I worry the parts chain for post 2016 dries up. I don’t believe Bafang will support B versions once their complete systems become the norm. My 2014 motors have no parts available.
 
I unsoldered all the FET legs first and pulled them out with the heat spreader still attached. Unsoldering the legs is very challenging because the holes are tight.
Another approach is to cut all the legs first and remove them one at a time. It’s easy to damage the traces if you pull while heating.
And after all that, there’s a good chance one of the FET drivers is blown.

Will a bbshd controller fit in a bbs2?
An external controller is another option.
 
tomjasz said:
I’d get a new controller. Unless it’s a pre 2016 and there are none available. Bafang is moving towards a Bosch like system and I worry the parts chain for post 2016 dries up. I don’t believe Bafang will support B versions once their complete systems become the norm. My 2014 motors have no parts available.

I got mine in 2014 so is the old version controller. Is been reliable and it was my fault the motor died. I found they are still available from Aliexpress but is going to take a month to arrive, hence why I'm trying to replace the mosfets myself.
 
fechter said:
I unsoldered all the FET legs first and pulled them out with the heat spreader still attached. Unsoldering the legs is very challenging because the holes are tight.
Another approach is to cut all the legs first and remove them one at a time. It’s easy to damage the traces if you pull while heating.
And after all that, there’s a good chance one of the FET drivers is blown.

Will a bbshd controller fit in a bbs2?
An external controller is another option.

Thanks for the suggestions.

I have 9 mosfets and so expect pulling them off still attached to the heatsink is going to be hard to get off without risk of damage to pcb. Unfortunately I can't cut the legs as the body of the mosfet are flush against the pcb. Bafang sure made it difficult to repair this.

WHen you say there is a good chance the FET driver is blown, are you saying there is another component apart from the FET that could be faulty?
 
Concerning that damaged inductor from the controller in my previous post, does anyone have a circuit diagram for this? The controller is from BBS02 36V 500W made in 2014.

I have little knowledge of electronics, would it still work if I removed the inductor?
 
If a FET blows, often it shorts and takes out the driver transistors with it. Sometimes they do, sometimes they don't.

You need the inductor to work. It's part of the voltage regulator. I'm not sure those have an actual part number on them so may be guesswork to find a replacement. Someone with a dead controller might have one. I probably have a dead controller somewhere, but it might take a while before I can go look for it.

I did find a picture of one without potting. It's marked 101, which I would assume is 100uH. If you find one even close it should work.
 
spockie said:
tomjasz said:
I’d get a new controller. Unless it’s a pre 2016 and there are none available. Bafang is moving towards a Bosch like system and I worry the parts chain for post 2016 dries up. I don’t believe Bafang will support B versions once their complete systems become the norm. My 2014 motors have no parts available.

I got mine in 2014 so is the old version controller. Is been reliable and it was my fault the motor died. I found they are still available from Aliexpress but is going to take a month to arrive, hence why I'm trying to replace the mosfets myself.

Please share the Aliexpress link? I have two 2014 motors and would like to stash at least one controller. THANKS!
 
I had the problem with a shorted mosfet
(there was water in the controller… old BBS01)
I had replaced it and now it has been working for over 2 years :D
loo9.jpg
 
tomjasz said:
spockie said:
tomjasz said:
I’d get a new controller. Unless it’s a pre 2016 and there are none available. Bafang is moving towards a Bosch like system and I worry the parts chain for post 2016 dries up. I don’t believe Bafang will support B versions once their complete systems become the norm. My 2014 motors have no parts available.

I got mine in 2014 so is the old version controller. Is been reliable and it was my fault the motor died. I found they are still available from Aliexpress but is going to take a month to arrive, hence why I'm trying to replace the mosfets myself.

Please share the Aliexpress link? I have two 2014 motors and would like to stash at least one controller. THANKS!

Select controller labelled 'old'
https://www.aliexpress.com/item/1005001720678099.html?spm=a2g0o.cart.0.0.6dfb3c00SPlr1V&mp=1

https://www.ebay.co.uk/itm/373768888519?var=642810047046
 
fechter said:
If a FET blows, often it shorts and takes out the driver transistors with it. Sometimes they do, sometimes they don't.

You need the inductor to work. It's part of the voltage regulator. I'm not sure those have an actual part number on them so may be guesswork to find a replacement. Someone with a dead controller might have one. I probably have a dead controller somewhere, but it might take a while before I can go look for it.

I did find a picture of one without potting. It's marked 101, which I would assume is 100uH. If you find one even close it should work.

Thanks for the valuable information. I'm more confident now in fixing it :)
 
I've noticed another problem. :(

I've lost a component, marked as green circle in the photo, by the DC-DC buck converter ic. I assume it is a resistor but could also be a capacitor, anyone know what the value of this is?
Missing resistor (1).jpg

Good news I've found only 1 mosfet (P75NF75) is faulty, which is by the green cable. Luckily these are cheap on ebay https://www.ebay.co.uk/itm/33429740...5pzpybTa2j69aiqC|clp:2334524|tkp:BFBM5Ieco-9f
 
The board layout on yours looks significantly different than the ones I have. Is that a really old one?

BBSHD voltage regulator area.jpg

BBS02:

BBS02 voltage regulator area.jpg
 
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