After 18 months of solid and trouble-free operation my BBS02 stopped working yesterday. Nothing happens when I try to switch it on, nothing is visible on the screen, and there is no sound from the motor.

I have two batteries, and the problem occurs with both of them on full charge, so I am thinking it isn't the battery.

I will try to test that the battery/cradle assembly provides power using a multimeter on the cable that links it to the motor, but I don't have enough knowledge of electrical engineering to know whether failing that test could simply be a symptom of the original problem.

I will also disconnect and clean all connectors.

I have done some internet research and noted the suggestion to troubleshoot by swapping out components. At this point I can't do that because I don't have any spares, but I have for some time been thinking about getting a BBS1000, which would give me a switch/screen assembly that I could swap out. However, I am not quite ready for the BBS1000 so would rather get my current setup working again before I go there.

I am thinking that I could simply order another switch/screen assembly at a less than prohibitive cost, which would at least allow me to identify or eliminate that as the cause. But I would prefer to have more confidence that the problem is there rather than in the controller within the motor, which seems to be the other possibility.

I am a modestly competent amateur bike mechanic but no kind of electrical engineer. Can anyone suggest any tests that I could perform to narrow down the problem, or point out any faults in my thinking about it as outlined above?

Thanks in advance

Ken

The first thing I would do is the obvious stuff like pull connecters apart and put them back together. Then - as you mentioned - put a new display in. The fact that it just stopped turning on at all makes me think the culprit is somewhere in the on/off-button area.

A lot of the new motor controllers have a over voltage sensor built in. If you over charge the batteries the system maybe be seeing a over voltage error and shutting down to protect itself. Just a thought. I would drain the battery a little just to see if that's the problem.

My system will cut off at 56v. A full charge is 54.2v on 4 sla batteries. That is avg voltage for a 48v system. and shuts down the system at 36.6 volts for the low voltage cut off. hope this helps

Thanks for these comments - most helpful. I will work through the various suggestions I have received and report back.

The 2015-2016 Bafang displays have been reported to be very crappy and glitch prone. Try replacing the display first, or even upgrade to a Luna color display. I went through 2 Bafang displays not powering up before going Luna and haven't had an issue since, at least not display related.

Also, Luna has a forum where there will be individuals with more BBS experience than here. My BBS02 has been recalcitrant a couple of times, but AFAICT it was a connection issue since when I squeezed them together the problem subsided.

Is this a BBS02 or BBSHD? I seem to remember this same thread on another e-bike forum... I hear of many BBSHD issues, but few BBS02 with "all stock programming and voltage." Most issues that I have personally heard of are on BBS## motors that have been over-volted and/or have programming changes made by their owners.

Regardless, the recommendations for resolution will likely be the same...

It is a BBS02. The display/switch is ok - works fine on another bafang installation - and the controller on the one which doesn't work appears to be dead when I try to plug in Dillenger's "switcheroonie" reprogramming device, which has previously worked well. So I have ordered another controller.