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BBS02 stops working intermittently after washing

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    BBS02 stops working intermittently after washing

    Well it figures something like this would happen. After over 4,000 miles of trouble-free riding, I decided to wash the bike for the first time since building it, because it was absolutely nasty around the bottom of the BBS02 motor and rear wheel. I thought I covered all the wire connections before using the garden hose and nozzle on the low pressure "shower" setting, but I guess not. Since washing the bicycle 3 days ago, I was riding with my son on his tagalong bike and the throttle and PAS suddenly just became completely unresponsive. The display was still working fine and still responding to button input, just nothing from the motor. After fiddling with wires for a minute it started working again.

    Then this morning just after I left my house to head to work, it happened again. Nothing from throttle or PAS. After jiggling and fiddling with wires it would sometimes work for a second on throttle, making the bike lurch forward, but then nothing. I had to ride the bike back home, up a hill, which was damn hard without assistance given the 70 pound loaded weight of the bike. And then just as I got back in front of my house, the dang thing starts working again!

    One odd thing that happened this morning was I shut off the switch on the battery, removed the battery from the cradle, then put it back and turned the display back on, and something weird happened that I've never seen before. The display showed 55.8 volts, but the battery fuel gauge in the upper right corner of the Luna display showed low battery level (yellow) for a second, then turned green and SLOWLY increased up to full. I've never seen that happen ever in 4,000+ miles of riding.

    So far it has worked fine when the bike has been at the house. I don't know how I will troubleshoot this thing when it seems like it works fine at home but then decides to act up out on the road.

    I purchased the kit in March 2017 with a 52V 13.5 aH bottle battery, so the motor should be the updated unit. Any suggestions would be awesome as I love the bike to death. I sure hope it's not the controller, but it seems to be working *most* of the time right now. It's just been those two instances of not working so far, with it working fine during other times.
    Last edited by PatrickGSR94; 07-03-2018, 05:15 AM.

    Something else I noticed is that I don't have the red light on the speed sensor by the rear wheel. I have no idea how long it's been this way, but I only noticed it after I washed the bike. But PAS was working after I washed the bike except for those 2 incidents. Also the speed still shows on the display like normal, so I'm not sure if the speed sensor has anything to do with this issue or not.


      So I have a theory that moisture may have found its way into one or both of the capped unused connectors on my BBS02 harness. I don't have a gear sensor so that wire sits capped off near the BB, and the right brake sensor is unused and capped, zip tied to the other wires and left brake cable in front of the handlebars. It's much more likely that moisture may have gotten into the gear sensor plug than the brake sensor, as I didn't really spray any water up around the handlebar area. So I'm guessing if there was a short inside the gear sensor plug, the controller would cut power to the motor.

      I blew some compressed air into both plugs so we'll see what happens.


        Bummer dude. Have you had any luck since then?

        I must say, you are game using a hose to clean your e-bike motor. I'm cautious to use a damp cloth/rag when I clean my unit - but most of the time, i clean it when dry. I've ridden a fair amount in the wet, but thats never direct water spray onto the motor.


          Hi I'm Dimyk fro France. Funny I have exactly the same event but after 2 000 kms only. On 7 July I met some viscous cow dung, I showered genly the motor to remove the thing and left the bike for one week. On 13th, the display seem ok but no power (0 amps at ammeter and of course no assistance) After testing, switching on off etc, I got three time the message 12H which may mean curent sensor down or overcurrent protection. Now after three days, the situation is stable. Every time I switch on (battery and display) I can modify the PAS or push the throttle, but no output (if I revolve the wheel the speed sensor works). The device is still under guarantee, I have the contact with Bafang Europ but I have the feeling that they will suggest me to purchase another controller, which I will probably do eventually, but of course I'm very curious to know how the Patrick's case will end up. Thanking you


            Hi- Brian from Cape Town . I have exactly the same problems with mine ( after riding in very heavy rain )

            Your posts were some time back so can you tell me please if you found what the fault was and if you managed to fix it ?

            thanks .


              Checking for water in brake and shift sensors is a good idea. Packing them with dielectric grease will help keep them dry.

              Be sure to have caps on them if not used!
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