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    DAPU hub motor don´t turn

    Hi,

    I am new in this forum, but it really seem to be a great place to find information!

    I´ve bought a used box-bike from a Swedish Company called Cargobike. I seller told me the battery was broken but otherwise everything should work.
    I bought a new battery to the bike, but unfortunately the motor does not run. :-(

    It has a DAPU controller, Display and DAPU rear hub motor (M123 RS) together with a PAS-sensor.

    The display is working correctly, but is constantly showing 0,0 km/h independent of my speed.

    I checked the PAS sensor because the magnet disc was a bit loose, but it seems to work OK. (+5V, GND supplied from Controller and signal from PAS is pulsing when pedaling , measured with volt-meter)
    I checked the motor windings, which also seems to be OK, see below.

    I disconnected the three feed cables from controller to the Hub motor.
    - Turning wheel backward- Easy
    Connected two of the motor-cables together
    - Turning wheel backward - More Hard
    Connected all three motor cables together
    - Turning wheel backward - Harder

    The motor is sensor less, means it has no Hall-sensors. It only have 3 feed lines + additional 3 small cables to the motor.
    The additional 3 small cables to the motor seems to be +5V, GND and signal which I believe is a speed signal.
    Measuring this speed signal (with volt meter), I could not see that it was toggeling. (constant 5V between GND to Speed signal)

    I therefore believe that the problem is with the speed sensor inside the Hub Motor.
    If the speed sensor does not provide any value, maybe the controller will not fire up the MOSFET¨s to the motor?

    I now wonder how i could resolve this issue.
    To disassemble the Hub motor seems difficult....

    My current idea is to install a throttle to the controller. (It seems to have an option to do this)
    Maybe with the throttle attached, the controller will not care about if there is any speed signal from the Hub motor and will fire anyway.
    What do you think?

    Regards
    Rikard



    #2
    Update:

    I temporarily bridged the speed sensor input (originally coming from Hub motor) with the PAS output and yes, now the speedo shows speed. :)
    Unfortunatly the motor does still not turn. :-(

    I got speed. :)

    Click image for larger version

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    Bridge:

    Click image for larger version

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    Comment


      #3
      Update:

      I know it´s not correct but I supplied directly voltage from an external voltage supply to the three power cables going to the windings on the motor.
      The motor is rotating as it should, so I think the motor-windings are OK....to bad that the controller is not outputting any power. :-(

      I think maybe next step would be to buy a new Controller to see if there is any difference.
      Otherwise I might buy a complete new E-bike kit and install. :-(

      Comment


        #4
        Hi RikardLandi,
        And welcome to the forum! :-)

        Originally posted by RikardLandi View Post
        Update:
        I temporarily bridged the speed sensor input (originally coming from Hub motor) with the PAS output and yes, now the speedo shows speed. :)
        Really quite clever! I commend you on your logic and troubleshooting awareness.


        Just a few thoughts...

        Did you replace the battery with the same voltage as the original? If not, change the settings in the display?
        Did you remove the brake cutouts from the system to eliminate them as a possible problem during testing?
        Did you try different PAS levels on the display when testing? Do you have a display manual?
        Did you get the PAS magnetic disc back in the same location, side toward sensor, and direction as originally mounted? Or try starting motor, pedaling in reverse?

        An external speed sensor may work, if the display allows for configuration... (IE: pulses per revolution and wheel size)

        https://lunacycle.com/parts/bafang-p...speedo-magnet/

        https://lunacycle.com/bafang-24-speedo-extension-cable/

        Other wise a motor hall sensor replacement sounds like fun! ;-)


        I have a bit of experience with throttle control if needed... Let me know if it's something you'd like to tackle. Have the controller wiring diagram?




        Regards,
        T.C.





        See my completed Magic Pie V5 rear hub motor E-Bike build HERE.

        Comment


          #5
          Hi Tommycat,

          Thanks!

          Yes, I replaced the battery with same voltage (36V) as original.
          Yes, brake cutouts are removed.
          Unfortunatly, I do not have the display manual but there seems not to be any PAS level settings....there are only settings for wheel size inside the menu. (I tried different wheel sizes in the menu)
          Yes, PAS magnetic disc is now replaced in the same location as before with the same direction as originally mounted. Did not try pedaling in Reverse, I will give it a try.

          Thanks for the links, I will try to add a throttle to this bike and also try to install an external speed sensor.

          I attach some pictures of the LCD I am having (it is the one in the middle in the picture) and the wiring diagram.

          Click image for larger version

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          Click image for larger version

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          Comment


            #6
            For information, I also made some more measurements between Controller Ground (V-) , Controller Battery (V+) and the three phase lines from the controller.
            I got there some suspect values, so I believe maybe some MOSFET in the controller is damaged....so will try to get another controller to test with.

            So seems to be (at least) two or three problems with my bike:
            - PAS disc loose (fixed)
            - Hall sensor (speed sensor) in wheel not giving any signal. (temporarly fixed)
            - MOSFET in controller most likely broken (not fixed)

            Regards
            Rikard

            Comment


              #7
              I just wanted to give a feedback, that my new controller (ordered from China) together with a new Display was received and installed. The motor is now running smoothly both with GAS (Throttle) and PAS (Pedal Assist) :-)

              I think even the performance is now better than before because I can now also disable the speed limit, I can make the motor go reverse and some other nice features.

              My next project will be to install some nice headlights / rearligths and horn on the bike which you can switch on and off from the handlebar.

              Thanks for the help on this issue.

              Regards
              Rikard

              Comment


              • Tommycat
                Tommycat commented
                Editing a comment
                Well done Rikard! Always a nice way to start the day seeing a success story. Thank you for the update. Looking forward to your upgrades

                Cheers,
                T.C.

              #8
              Hi Rikard
              I am from Sweden too (Stockholm) and have basically the same issue you have.. I have a BH Bike with a DAPU motor a working 48v battery (measured it) but I can in no way get it to run!
              The ugly part is that the display is from BH Bikes too and I am afraid that i need to buy a controller too.. can you please send a picture of the Motor hub you have (i have a rear hub motor of 500W) as well as the controller you bought please?
              I need to see what kind of connectors i should search for..
              Thank you in advance buddy!

              Comment


                #9
                Hi can anyone tell me wear I can get Dapu l c d display manuals

                Comment

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