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BBSHD cutting off 30 seconds

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    BBSHD cutting off 30 seconds

    Good day Luna fam. I have always used a BBSHD with no speed sensor and the pedal assist and throttle would function normally, even with an ERROR 21 code on the display.

    I recently replaced the old BSHD controller and bought a brand new BBSHD from Luna.

    Now I am having difficulty with both BBSHD motors staying on.

    The issue is that when the black and white display is turned ON it runs great for 20-30 seconds, but as soon as an ERROR 21 code pops up, the assist and throttle cut off. The display remains on but the bafang does not function.

    I have tried multiple luna batteries. It seems more like a controller / display issue.

    Any ideas for troubleshooting this problem?

    Disable auto-shutoff in the display. Not all displays have this but the color ones do.


      #2, Received a BBSHD on Friday, with LUNA color display. Got around to putting bike that I bought it for together enough to take for a ride, and I am experiencing EXACTLY the same issue (ERROR 21 H). About to be restarting every 30 seconds to make it home. When I get there, I'll throw on another display to troubleshoot. Any help on this would be appreciated.

      I'll look up how to disable auto shutoff; hope to improve my experience getting home!
      Last edited by Rio; 07-25-2018, 05:17 PM.


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          Error 21 - Speed sensor error
          If you install the speed sensor then the problem should go away.


            The way the supplied speed sensor is, there isn't any way to get the spacing correct on this frame. Well, if I got an extension cable, it may work on the upper bar. I'll try to rig it up somehow and see if it solves my problem. I didn't have to have the speed sensor working on the other two Bafang motors I bought from Luna. I'm thinking this is the easiest of the three to invest time in working out the issue with because it's brand new.

            I tried two different stock display units, and still needing to restart the system every 30 seconds if I'm on the throttle. This has made me pretty confident in saying that it's not the display.

            UPDATE: Thanks for your advice. The speed sensor did the trick. I could get the spacing right on the chain side, and think I have the cord pretty well protected with zip ties.

            This bike is blowing away my expectations! It really performs; WOW!
            Last edited by Rio; 07-27-2018, 07:45 AM.