Please Help. My BBs02 750w c965a motor won't react


New Member
I got my kit last week. I bought the Bafang 48v 750w bbs02 motor with c965a display and 48V 10.4ah bottle holder mount lithium Li-ion electric bike battery with samsung cells. I put it together and went for first ride today. It was awesome. I did 9 km with both throttle and power assist 1-3 settings. I then decided to see how fast i can get it up to and went for top speed. Right as I got to 45 km, i let off the throttle, and motor would not respond after that. I do have power still since the display has power. i thought it might be the throttle, but even when pedaling in power asssist, all 3 modes, there is nothing from the motor.

Is there a fail safe mode or something or did my motor burn out. I was so excited to finally get it. Spent 3 days building it and enjoyed 9 km. What a bummer.
Is there an error code shown on the display?

Do you have the brake cut offs fitted, the generic hydraulic switch and magnet type specifically? If the magnet gets too far from the sensor the motor won't start and no errors will be reported because the controller will think you are braking.
I do have power still since the display has power

Step 1

Disconnect both brake electric connectors
Disconnect throttle electric connector
make sure the main connection between the C965 and motor/controller is fully engaged.
Ride the bike with PAS level zero. If you are registering speed the speed sensor is working.
Increase PAS to level 1. If you have motor power now your problem is either the throttle or one of the brakes (electric switch). If you don't have power, you may have a failed controller.

If you do have power after doing the above, plug in the throttle. If the throttle works, plug in one of the brake electrical connection, does the throttle still work? Plug in the other and repeat. If at any time one of the components you plug in prevents the motor from functioning there's your problem.

Hopefully it isn't a failed controller....

Court J.
As CourtJ says those are the things to start with..

Was this run on the flat or an incline?

Is the motor the latest model, you`ll see the date of manufacture right underneath.

You didn`t check the motor to see if it felt hot?

Hopefully not a fried controller,

Court, good tips. AFAIK, if it's a failed controller there is almost always a 2 digit error code displayed - had oneself once - and the same goes for malfunctioning speed sensor, etc. So, if there's no code, it's most probably a brake cutoff thing going on.
This was on a flat part of the road. I do not have any faults on the display.

I will try the above suggestions to diagnose the throttle and/or brakes. It's supposed to be the latest 2015 model. I will check motor when I get home for date.

I did check temp on motor. It was a little later and not right away. I rode the bike for about 5 blocks because I didn't know what it was. It was warm, but not very hot by then.

I did check the disconnects on both sides. I thought maybe one of them got stuck, but they seemed ok.
I did have a chance to check it today. I charged the battery overnight. I unplugged the shifters and throttle and left display connected. I left it in P0 and went around the block. The speedometer did work. I then put it in P1 and nothing. Same thing in P2 and P3. It looks like it the controller. Hopefully, the seller will come through with a new one.