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Speed sensor not working?

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    Speed sensor not working?

    I have a new install of a BBSHD kit with speed and brake sensors on a recumbent tricycle (Steintrikes Wild One). It does not seem relevant in this case, but I am also using an Eggrider instead of Bafang display.

    A. Everything about motor drive works okay, except the speed sensor.

    Because speed sensor is not working, I will start off running okay (pedals or throttle, brake sensors work, too), but then after a minute I get an E21 error code, and power to the motor is shut off (display still on and looking normal otherwise, but E21 showing). If power the display computer off / on, I can run again until E21 occurs again.

    Speed sensor is very well installed. Magnet and sensor are exactly opposite and parallel, and actually only 1 mm apart (I have actually made them brush but still did not register.)

    Sensor is simply unable to "read" the passage of the magnet, no matter how close it is. Its red light comes on with power, and simply remains on continuously. No blinking.

    Even when I manually play with bringing the magnet and sensor together, I have only twice been able to get the light to go out and come back on. Strangely enough, this happened when I purposely mis-oriented the two at an angle to one another and touch.

    When exactly facing and parallel as recommended, there has never been any response to magnet whatsoever. Solid red light.

    Think I need a new speed sensor?

    one fact I forgot that is also probably not pertinent - the wheel it is on is 24", so there is no wheel size selected in software 9(there is no option for 24) - jut the circumference is entered.

    Has anyone found or tried a stronger magnet, different sensor?
    (Luna does not have the replacement sensor in stock. )

    Have you tried using the other side of the magnet? See also...
    See my completed Magic Pie V5 rear hub motor E-Bike build HERE.


    • Muggsy
      Muggsy commented
      Editing a comment
      hi tommycat
      Not sure why backwards would be better, but no, that did not work either. i have seen that article and it provides no help. have spent much time fooling with exact location and orientation.

    • Tommycat
      Tommycat commented
      Editing a comment
      One time I saw where an owner changed the magnet around and it worked... using the opposite polarity. (coincidence?) I scrapped out an old computer hard drive and found their magnets to be quite impressive! The sensor is loading in my cart ready for check-out, perhaps they are back in stock?
      Last edited by Tommycat; 05-16-2019, 05:31 AM.

    also check the magnet orientation it should have a straight angle to the wheel


      Is the magnet between the lines on the sensor? Not at the end, middle?
      Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.


        They apparently are back in stock - thanks. Luna support is not getting back in any hurry so I just ordered a replacement. s/b here in a couple of days.


          Received new sensor and replaced. Still pretty pick about alignment, but it now works (and I am now working my next problem. #;>)
          So, I guess it is possible to have a marginal/bad speed sensor, tho apparently it does not happen often.