Bafang BBSxx - fault finding and fixes

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
Ben Abraham
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Re: Bafang BBSxx - fault finding and fixes

Post by Ben Abraham » Oct 11, 2017 10:13 pm

I went ahead with the Quiksteel solution (technically it was a JBWeld steel stick). It works! At least for now... I took it out for a spin last night and rode it in to work today without problem. I hadn't realised how noisy the thing had gotten! Silent as a ninja now.

To true it, I removed the stator, applied the epoxy, set it in the bearing covered by clingwrap to prevent it from bonding to the bearing... This yielded a built-up axle with 7.8-7.9 mm diameter. I put it in the case without the stator with both rotor ends in their bearings and the case screwed shut to keep it true while the JBWeld cured. When I rebuilt motor I applied Locktite 609 to keep it in the bearing. It seems to work fine -- the only issue is that the freewheel seems a bit less free than it was... but this can't be the rotor because both the shaft and nylon gear clutch will be disengaged for this action. The bike performs better than it did when the problem was diagnosed. If a problem emerges with the bearing later on, then I'll cross that bridge then.

I'm amazed by how quiet it is now!

Thanks, everyone! :D

Ben Abraham
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Re: Bafang BBSxx - fault finding and fixes

Post by Ben Abraham » Oct 11, 2017 10:15 pm

Oh, yeah and I took the opportunity to Mobilegrease 28 the whole thing. Should I have greased the clutch? I did... is this why it's a bit more viscous-feeling?

I got the motor from Emax-Ebikes back in 2013. Definitely, absolutely, positively out of warranty.

Still no contact from GBK about spare parts and the order is still "processing". If I don't hear from them by the end of the week I'll probably go to PayPal and yank the order.

Ben Abraham
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Re: Bafang BBSxx - fault finding and fixes

Post by Ben Abraham » Oct 11, 2017 10:17 pm

Whoops! Check that... GBK did send the order and now I have a tracking #. Apologies for the mix-up; I didn't see the email at first...
Probably should have ordered a spare bearing just in case... ah well. If it gets here OK then I'll keep them in mind in the future and get it in the next round.

tomjasz
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Re: Bafang BBSxx - fault finding and fixes

Post by tomjasz » Nov 10, 2017 12:23 pm

Lurkin wrote:
I will get round to posting up the grease docs from Bafang when I get time.

Any hope for the curious?
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.

spockie
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Re: Stuck on assist 1 & display buttons unresponsive.

Post by spockie » Nov 20, 2017 10:38 am

I have a dead C961 display and cannot power up the motor. Absolutely no response from the power, + and - display buttons.

I'm able to program the motor controller using PC software and programming cable and so can confirm communication with the motor is OK. I checked the cabling for any insulation wear and went through reinserting all the plugs to make sure it made proper contact. Also checked the battery output which is around 40V. I have now disassembled the display unit and replaced a button CR2032 battery as it was slightly corroded. I used a meter to check for continuity to the buttons and plug and all tested fine.

Some background information before this happened. I previously had an intermittent fault with the C961 display where it was stuck on power level 1 which suddenly cured itself and working fine for many weeks. However lately it has been difficult to power up and took several attempt to work by disconnecting and connecting the battery. With the current fault, I noticed when switching off the battery by the switch, the switch light remains on for a few seconds before distinguishing.

Before I buy a new display unit, I wonder if anyone know what might be the cause of the fault.

Lurkin
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Re: Bafang BBSxx - fault finding and fixes

Post by Lurkin » Nov 20, 2017 3:31 pm

Water ingress is typically what kills these screens and causes intermittent faults with them.

spockie
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Re: Bafang BBSxx - fault finding and fixes

Post by spockie » Nov 20, 2017 4:32 pm

So is likely it's the display that's faulty. When I looked inside the display it seems dry and unable to find or smell any burnt component.

Lurkin
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Re: Bafang BBSxx - fault finding and fixes

Post by Lurkin » Nov 20, 2017 8:45 pm

Leave it somewhere where it would definitely dry out even if you cannot see it for 12 hours or so. Then plug it in, see how you get on. If that not it, I would be inspect the plugs and using a multimeter to ensure continuity on each part of the loom.

I never got round to trying to repair my display. Totally possible to use these units without the display and relying on the default settings of the motor controller to power/instruct the motor unit, which is what I have done since.

I started a project to investigate replacing the display unit with something more universal/ swap it out for just buttons and a more simple display but never finished it. There is a german pedelec site where they have achieved this but I never got a response out of them. They have produced a homegrown cycle analyst device to replace the display altogether.. may give one of these a go in the future. Advantage being, you can choose the display it interacts with rather than being required to use non waterproof king meter displays like this one.

spockie
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Re: Bafang BBSxx - fault finding and fixes

Post by spockie » Nov 21, 2017 6:24 pm

Lurkin - That's an interesting project you started, shame you never finished it. I was thinking maybe just the buttons and a 7 segment display to display PAS level for a minimalist look.

Back to my problem, I searched this forum for a dead display but didn't find anything conclusive. However I stumbled onto a thread about using the motor without the display and found more information at this sitehttp://www.poweredride.com/info/dump-yo ... ay-options. Basically it involves shorting the PL and P+ pins on the plug that connects to the display. Since I already have a programming cable which have this, I plugged this in and hey presto, my bike came back to life. :D

Is now obvious that my display is faulty and I'll have to order a new one. Had a brief test ride and found I don't miss the display except for changing PAS level and would be great if a solution existed for this type of setup.

spockie
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Re: Bafang BBSxx - fault finding and fixes

Post by spockie » Nov 21, 2017 7:04 pm

My prayer may have been answered. While searching for the best deal for a C961 display on Aliexpress, I come across module with buttons and leds https://www.aliexpress.com/item/Free-sh ... eLevelAB=0

It seems only 5 PAS are available, there's no manual available so short on information. Think I'll start a new thread on this for better visibility.

Lurkin
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Re: Bafang BBSxx - fault finding and fixes

Post by Lurkin » Nov 21, 2017 8:52 pm

Thats perfect and pretty much exactly what I wanted after being in an identical position to you. Interesting, pretty sure the same guys used to sell a (appearingly) knock off kingmeter screen which was cheaper than the correct replacement. Nice man, are you ordering one of these? Otherwise I may have to... 8)

spockie
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Re: Bafang BBSxx - fault finding and fixes

Post by spockie » Nov 22, 2017 6:44 pm

I'm now not too sure whether to get the new DPE-12 led display. If there is a fault condition in the motor. normal LCD display would display the appropriate error code, I can't see the DPE-12 would do this. From people's experience in fault finding, is the error code vital to this?

bretster
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Re: Bafang BBSxx - fault finding and fixes

Post by bretster » Jan 31, 2018 11:52 am

I have the dreaded growling gear noise on a 500w 36v BBS02 with about 3000km on it. I ripped it apart and all the gears are fine. It appears the motor shaft is the problem as it measured 7.9mm, but on the GEAR side, not the motor side. The motor side also feels a little loose, despite measuring 8.0mm (just using calipers...not very accurate). Has anyone had this problem on the gear side and used Loctite to fix it? I am thinking I might need to loctite both ends, which would mean possibly never being able to open it up again. Any ideas that don't involve loctite on both ends?

Thanks for any information you might provide!

Bret

heathcliff
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Re: Bafang BBSxx - fault finding and fixes

Post by heathcliff » Apr 04, 2018 4:04 pm

bretster wrote:
Jan 31, 2018 11:52 am
I have the dreaded growling gear noise on a 500w 36v BBS02 with about 3000km on it. I ripped it apart and all the gears are fine. It appears the motor shaft is the problem as it measured 7.9mm, but on the GEAR side, not the motor side. The motor side also feels a little loose, despite measuring 8.0mm (just using calipers...not very accurate). Has anyone had this problem on the gear side and used Loctite to fix it? I am thinking I might need to loctite both ends, which would mean possibly never being able to open it up again. Any ideas that don't involve loctite on both ends?

Thanks for any information you might provide!

Bret
Hi Bret,

That is precisely what happened to me after my first overhaul at 1500kms. The next year, it started to make that noise when the motor was heating up. With the motor cool, it was utterly silent. After a moderate to strong effort, the noise started again. I only made 500 kms so far that year so it wasn't normal.

Note that it's a BBS02B so it's completely different that the BBS02.

In the BBS02B, the bearing on the motor side is already loctited to the rotor at factory otherwise tolerances has changed and the fit is extremely tight. So I never tried to separate them. If it ain't broke, don't fix it. I did applied yellow loctite though between the outer side of the bearing and its casing.

See photo where the bearing is stuck to the rotor: https://www.ts-export.com/_mb/bbs02_31d ... GP0378.JPG

For a good measure, I applied yellow loctite as well on the both sides of the gear side bearing effectively locking everything into place.

I applied a small amount of loctite, so with some prying force or heat from a torch, the motor could be reopened.

It's deadly silent since and I made 2200 more kms afterwards.

Hope that helps.

Sorry for the delay in replying, I thought that thread was dead.

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