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  • Rix Ryds
    replied
    Not easily. If you remove the two small screws and gently pry upward around the edges the circuit board can be freed from the housing. You would then need to remove the grey potting material very carefully to expose all of the board components. At that point you could replace your FETs, IF that's the problem. If not your kind of stuck unless you want to reverse engineer the whole thing, as Bafang keeps the circuit schematic quite secret. Even if you had a schematic diagram of the circuit, you have to be top notch at soldering as most of the circuit uses micro components that are easily damaged by hand soldering. My suggestion is to go ahead and buy another controller. I keep one as a spare, along with a display, throttle and main cable, and it has been a valuable tool in diagnosing problems. I did think of a couple of things:
    Do you use a gear sensor? If so unplug it. With the controller hooked up to the motor and a display, throttle and battery hooked up (doesn't need to be on bike), when you hit the throttle do you get a power indication on the display? If you do the FETs are OK, and you may have bad phase hall sensors. Had this happen on a Cyclone 3k that suffered from 'heat soak'.

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  • Rider
    replied
    The China seller insists I ship the bad one to them for "repair." I've never heard of anyone repairing a BBS## controller, they simply replace them.

    I mat hit Luna up on my next drive through LA to confirm this one is bad before sending it off.

    Q: CAN BBS## CONTROLLERS BE DISASSEMBLED AND REPAIRED?

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  • Rix Ryds
    replied
    Look in the builder for hire section. Several in your area. Luna would also check it for you and sell you a new one as well.

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  • Rider
    replied
    Removed the controller using the Luna sticky thread video. All the connections stayed in tact and were connected properly to begin with. Anyone know of a ebike shop in Orange County, CA that might have a good loose controller that I can connect to verify this one is bad?

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  • Rider
    replied
    BTW, I was at the Harley Davidson dealer recently to pick up a relative dropping off his bike and noted their excellent accessary displays. They have all their seat offered covered with leather that has "DEMO" stamped all over it, as well as, wind screens and pipes, also stamped all over with the word "DEMO" in bright orange. How cool is that?

    You can try any of their accessories out in "DEMO" form before purchase. That way you know if you like it before ordering in the color you want.

    This is just what we DIY Bafang BBS## users need at a co-op facility to diagnose problems, so you order the correct broke part. We can always dream about things that make life easier. ;-)

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  • Rider
    replied
    Okay the seller wants me to send the controller to China (at my cost), they will "repair" it and send it back for $25 return shipping...

    First off, can these even be opened up and repaired? The attached picture looks like it is pretty much a solid state construction within all that grey stuff. If I remove those two screws can I see inside to make a repair?

    All this controller "repair" nonsense seems like a waste of time. I offered the seller $50 (my cost to ship it each way) and asked them to simply send out a new controller under warranty. That way they will be $25 ahead (assuming $25 is their really return shipping cost) and not have to mess with repairing anything. That is much more efficient for both of us. Waiting for an answer now...

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  • Rix Ryds
    replied
    Honestly Rider, no. I think you may be in uncharted territory, at least for me! Good luck though, and keep us posted, I am very interested in your findings!

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  • Rider
    replied
    Originally posted by max_volt View Post
    per the blog: Some users report a very faint click when they hit the throttle which is the power cut out as the battery shorts to ground from the blown mosfets. The only solution to this problem is replacing the controller
    Thank you MV. It really sounds like the controller went out (mosfets). Is there any way to tell by looking at it (serial numbers?) if my controller is the newer 3077 with 9 mosfets like the seller claimed when purchased?

    Because it went out without any abuse, I'm wondering if I got what I paid for...

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  • max_volt
    replied
    per the blog: Some users report a very faint click when they hit the throttle which is the power cut out as the battery shorts to ground from the blown mosfets. The only solution to this problem is replacing the controller
    In so many ways Bafang's BBS02 750W drive unit is a dream come true. Almost anyone with very little technical know how can order a drive kit and 48v-52v battery pack and have it installed and running on almost any bike with 2-3 hours of work. Any other mid-drive ebike kit is going to take a…

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  • Rider
    replied
    I buttoned it back up and removed the motor from the bike. I decided not to mess with it until I hear from retailer regarding the 1 year warranty,

    With that said, I did connect the battery once the unit was off and on the workbench. I went into the advanced settings and Error Codes, but there are no error codes listed ( the retailer asked me to do that first). When I hit the throttle I can hear a very slight "click" from inside the motor and the display only reads "26W" no matter what 1-9 level it is set to.

    Does that bring any new light to identifying the problem? Thx.

    Leave a comment:


  • Rix Ryds
    replied
    You're well on your way to having it repaired! Good luck!

    Leave a comment:


  • Rider
    replied
    Originally posted by Rix Ryds View Post
    OK, the fact that the throttle quit as well rules out the PAS hall sensors. However, there are three more hall sensors that are used for the three phases. These connect to the controller through a white plug that you can see if you remove the controller. This white plug is one of two problematic areas in the BBSxx series motors. I just helped a forum member "Gabriel' with his problem and it turned out to be the white plug. The first time I disassembled a BBSHD I carefully cut around the plug to free it from the silicon sealant, depressed the locking tab and gently pulled the plug loose. I was quite surprised to find that it had pulled one of the pins right off the board from below! When I went to repair it ALL of the pins on the board had 'cold' solder joints and pulled loose with ease. I'd be willing to bet good money you will find a problem with this white plug or the white socket it plugs into! Especially given that both PAS and throttle failed, the display comes on as expected, and you were riding within reasonable limits. Check it out carefully, I believe your problem is there! Good luck!
    Thank you RR! I am going to pull the controller off today, so the white plug will be getting disconnected. I did watch the video in a sticky thread on this forum for trouble shooting the BBS## motors. That was VERY helpful to see how it's done.

    I think I will pull the entire motor and put in on the bench for easy disassemble...

    Anyone interested in a converted to 29+ or 29 or 27.5+ or 27.5 or 26+ or 26 (your choice) "BBS02 READY" Electra Lux Aluminum 3-Speed cruiser with chain guard mounts? Original tires are like new and it takes 120mm or 135mm disc brake rear wheels! PM me if interested. I see a Soma Juice or Surly ECR coming my way if I have to take this one apart. ;-)
    Last edited by Rider; 11-25-2017, 10:30 AM.

    Leave a comment:


  • JPLabs
    commented on 's reply
    I've notice my drag seemingly zero sometimes, and high other times. Figured out pretty quickly that what gear the bike is in makes a huge difference in the drag severity. So, again, probably nothing to worry you, there. If the motor was melted inside, plastic gear or worse, you would be able to tell, I think. It would be 'chunky' or get stuck some places, not just 'smoothly lumpy'. Like good turkey gravy.

  • Rix Ryds
    replied

    OK, the fact that the throttle quit as well rules out the PAS hall sensors. However, there are three more hall sensors that are used for the three phases. These connect to the controller through a white plug that you can see if you remove the controller. This white plug is one of two problematic areas in the BBSxx series motors. I just helped a forum member "Gabriel' with his problem and it turned out to be the white plug. The first time I disassembled a BBSHD I carefully cut around the plug to free it from the silicon sealant, depressed the locking tab and gently pulled the plug loose. I was quite surprised to find that it had pulled one of the pins right off the board from below! When I went to repair it ALL of the pins on the board had 'cold' solder joints and pulled loose with ease. I'd be willing to bet good money you will find a problem with this white plug or the white socket it plugs into! Especially given that both PAS and throttle failed, the display comes on as expected, and you were riding within reasonable limits. Check it out carefully, I believe your problem is there! Good luck!

    Leave a comment:


  • Rider
    replied
    Originally posted by JPLabs View Post
    Motor drag when moving the rear wheel backwards is normal. The freewheel on the crank will spin the motor in reverse, so you feel the cogging from the magnets, only when the chain is turning the kit backwards.
    So, that part is nothing to worry about, unless it is particularly hard to spin. Should still move pretty easily, but you definitely will feel some 'lumpy' drag.

    FYI.
    It has obvious "lumpy drag." That is a perfect description of what it does, but it seems like it wasn't that strong before or I would have noticed it. I don't remember it on my other BBS02B ride either.

    Wish I had a handy independent controller to slap in to eliminate that first. Isn't there a way to apply a power source to a standalone controller to test it?

    Leave a comment:

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