Bafang BBSHD motor cuts off

[Donnie]

My Bafang BBSHD motor cuts off every couple blocks. Sometime when accelerating, sometime when coasting.
It can happen under any condition.
I have to turn display off then on for it to come back on.
I have tried unplugging brake and speed sensors.
Please help figure out what the problem is.
Thank you

 

[BiggKidd]

Go through the whole wiring system and check / double check all the connectors and connections. It may well be an internal problem but best to make sure it's not external first. Always start with the simple stuff first. While you're checking the connections and connectors keep your eyes open for anything that looks like it may have gotten hot at any point. Loose wires / connections often leave tell tale signs.
Good Luck!

 

[m@Robertson]

Unplugging the speed sensor is a way to induce a problem, not solve it (its not a permanent problem just an error code, that on some displays you can shut off via the settings). So after you are done with checking that bit, plug that sucker back in again.

I'll echo the advice from @BiggKidd . Usually when doing diagnosis on one of these mystery problems, after you have figured out that there is no visually obvious flaw in the wiring, you start replacing stuff. Cheapest stuff first and hope at some point the problem goes away. I would start with the wiring harness. Even though it may look like its fine, a wire could be compromised within otherwise intact-looking insulation. The wiring harness controls several different things so its a good thing to start with. The last item on the list would be the motor controller which is the opposite of cheap and easy to swap out.

If your motor is cutting out but the display is uninterrupted, then that should count out the battery as the problem, but I would still check the wiring from motor to power source to try and ensure its all in one piece.

A cheap display to put on to ensure the problem is not your existing display would be the DZ40. You can get them for as little as $25 on Amazon, Ebay or AliExpress. They're my personal favorite as a minimalist display. The cheap cost is a bonus but not the reason I use them.

 

[Byrd]

My 36 Volt A2B cuts off intermittently. I can push power off, then back on, and it works for a while, then cuts off again. Tightened the one connection I could find, and it worked for a while, but now back to the trouble. If battery is going bad, can I replace cells? Which cells to shop for? I don't find any replacement batteries for sale. (Mine is a twist throttle unrelated to the 7-speed transmission; I like using them independently or in conjunction.)

 

[Annieolnie]

Which A2B is it and how old is it? If you ignore the throttle and just use pedal assist does it still cut out? Does your twist throttle have hall sensors? You can also check the battery voltage when it is fully charged to see what voltage the cells are holding.

 

[Byrd]

I think it's 2012. There is no pedal assist. Don't know what hall sensors are. I'll try to check the voltage, I suppose by probing two of the three holes where the charger plugs in. I have felt a slight wavering of the power before it cuts off. So far, it always restarts after pushing the on/off switch, but then might not go far before cutting off again.

I'm also in the midst of trying to revive my 2012 Mitsubishi MiEV. Replacing one cell that was low voltage. Hoping that fixes it. Have to raise it back up and connect all wires before finding out if it will take a charge again. Wondering if a similar process can be done on my bike battery.

 

[Annieolnie]

13 yrs of service from an ebike battery is far more then I would ever expect. You can have it rebuilt. A lot of people on this forum use Northeast Battery Systems in Conn. You can check their website and give Kevin a call to find out your options.

 

[HumanPerson]

13 yrs of service from an ebike battery is far more then I would ever expect. You can have it rebuilt. A lot of people on this forum use Northeast Battery Systems in Conn. You can check their website and give Kevin a call to find out your options.

https://www.northeastbatterysystems.com/

Kevin
(860) 951-1468
nebattsys@gmail.com