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    BBSHD Mystery

    I have two BBSHD bikes, both operational for 1-2 years, both bbshd's from Lunda. They both have Dolphin 52V packs, one from Luna and one from BafangUSA. Let's call them Bike A and Bike B. A few days ago my son had a small wipe out on Bike A, which twisted the handlebars around which pulled open some of the display and brake connectors. We plugged them back in. When I turned on the battery, there was the briefest of surges in the motor, then nothing (this was before the on button of the motor had been pressed.) But the system would not turn on. Then I tried my Bike B battery in Bike A. Same result.

    But I put both batteries on my operational bike (Bike B) and found that the Bike B battery powered the system up but Bike A battery would not.

    I then thought it might be the display and on/off button of the system, so I switched them. On Bike A I got the same tiny surge in the motor but the system would not turn on. BUT NOW I FIND THAT BOTH BATTERIES WON'T WORK IN BIKE B EITHER. BIKE BATTERY B SHOWS IT IS TAKING A CHARGE BUT WON'T DISCHARGE. BIKE BATTERY A WON'T EVEN TAKE A CHARGE. THE CHARGER DISPLAYS SO ACTIVITY.

    HELP!!!

    #2
    Did you check the fuses in the dolphins?

    Comment


      #3
      Under the flap labeled "fuse", there is no fuse. I opened up a previous Dolphin that had problems and it had no fuse either.

      Comment


      • AZguy
        AZguy commented
        Editing a comment
        Odd - I have four dolphins from four different sources and all have fuses (30A blade)

      #4
      I will check each of them. Thanks!

      Comment


        #5
        "Odd - I have four dolphins from four different sources and all have fuses (30A blade)" AZguy,

        I checked both batteries. The Dolphin from Luna has no fuse or socket under the "Fuse" flap. The one from BafangUSA does have a fuse and socket and when I replaced the 40A fuse today, it works again.
        Were any of of your Dolphins from Luna?



        Attached Files

        Comment


          #6
          Originally posted by Stu Summer View Post
          ...Were any of of your Dolphins from Luna?
          I double checked them all just to make sure I wasn't remembering wrong (my memory is a little flaky these days) and all four have fuses.

          Two were from rad power (one came with my bike from them a couple of years ago and the other from a guy who got the wrong battery for his bike from rad and sold it to me), another from an ebike part importer in the san dego area that definitely had different electronics than the rad batts. The fourth? I'm not sure where it came from - I don't remember and although I keep a list of my online purchases I didn't find it readily. I know I bought a shark from luna but not sure about that last dolphin...

          Comment


            #7
            Sounds like bike A has some serious problems! I'd be looking for stretched or torn wiring that could be shorting out. You may have to buy a new wiring harness and maybe a controller.

            Comment


              #8
              So when I connect a battery to the power lines to the bbshd and turn it on, the wires from the battery to the controller literally jump/jerk and the fuse in the dolphin pack is blown (even though there is no visible damage to the fuse. A new fuse starts the process over again.). What would cause the leads to jerk? Further mystery: the leads continuity test just fine.

              Comment


                #9
                Originally posted by Stu Summer View Post
                So when I connect a battery to the power lines to the bbshd and turn it on, the wires from the battery to the controller literally jump/jerk and the fuse in the dolphin pack is blown (even though there is no visible damage to the fuse. A new fuse starts the process over again.). What would cause the leads to jerk? Further mystery: the leads continuity test just fine.
                High rate of current rise causes a magnetic field that makes wires jump. Never saw a bike do that! Just welders.

                It sounds like you might have a low resistance, dead short, to me. I don't think inrush current for a healthy system can do that.

                See what AZ guy adds, in about 2 minutes ;)
                Last edited by JPLabs; 03-15-2018, 02:48 PM.
                Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

                Comment


                • AZguy
                  AZguy commented
                  Editing a comment
                  LOL... inrush could do that - the currents and magnetic fields are pretty much the same but the energy and duration of an inrush event will most likely be much smaller. I measure 1000µF on a BBSHD controller! That's a *lot* of capacitance to throw 50V on...

                  I agree that based on his descriptions it is much more likely he's got some bad short....

                #10
                Thanks guys! Is the best way to find the short continuity testing? I keep poking holes in the wires to find the break.

                Comment


                • AZguy
                  AZguy commented
                  Editing a comment
                  Unfortunately when using a DVM it comes down to isolating parts in order to find the short.

                • max_volt
                  max_volt commented
                  Editing a comment
                  More like a short than a break. Check from the battery cradle negative to any and all wires. Only one should be very low ohms.
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