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Help trouble shooting Bafang BBS02

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    Help trouble shooting Bafang BBS02


    (long post but please help)

    so the chain of unfortunate events went as follows:

    I tried to clean my bike with running water, after I had a fall on fine dusty road. After that the motor worked fine that day.

    The next day when I wanted to go to work, the motor did not work. I had no error msg, the display was working, the speed was showing ok, but if I pressed the - button (for waking assist) nothing happened and if I paddled the motor did not assist. I don't have shift sensor and I disconnected the brake sensor - no difference.

    So I read on the net, that some people had similar problems when they were riding in cold wet conditions and water got into the controller. So I removed the controller and there was water in there. I left it for 3 days to dry and when I tried to run it half disassembly it worked some. So I sprayed the controller with some conformal coating and closed the motor.

    Now I had different problems when I tried to ride. Sometime the motor would assist me and some time it would not. Also when I tired using walk assist it would work funny. It would a) start normally with a speed of 7-8 km/h or b) it would start at full blast and go for 30 km/h (lifted rear wheel).

    The not wanting to assist me was strange and I had the idea. On the shift sensor there are 5V, gnd and another signal. The 5V is capable in driving some current but the unknown signal (5v) was just floating. If I connected and amp meter form this floating signal to ground there was no current. I I tied the unknown signal to 5V via 800 ohm resistor.

    Now I have different behaviour. The motor helps normally. BUT the walking assist is still working funny (no change) and when I tested some more I saw that the power reading on the display is jumping up and down.

    Any ideas what to try, do, test?

    I'm thing of 2 things: opening up the motor further and looking at the PAS board and the board on the stator or replacing the controller. A local guy that installs bafangs offered to reset the motor - but I'm sceptical if it would do anything.

    Best regards,

    Edit : I have the B version of controller. 48V/750W

    If you damaged the controller from initial exposure to water, your next step should be trying to replace the controller.

    If something was damaged from water, it does not reverse that damage by spraying it with conformal coating. Not would it typically fix that damage by letting it air out either.

    However it would be a good idea to take those sorts of precautionary steps BEFORE exposing it to water.


      Originally posted by paxtana View Post

      However it would be a good idea to take those sorts of precautionary steps BEFORE exposing it to water.
      I know but I had no way of telling that the seal was superglued into place with a fold in it :(

      So this sounds like a damaged controller to you? Or could it be the hall sensors/pas sensor?