Bafang bpm speed sensor error

[jonny]

Hi friend, my new kit have 850C display.
It show me 21h error, that mean speed sensor error.
I opened hub motor bafang bpm to see if speed sensor was broken but I not found it.
My motor have it? I seen only 3 sensor that work with 3 wire of phase motor on right side (h1 h2 h3 yellow blue green cable on right side) Each color of phase correspond at third foot of one of 3 sensor.
White wire on left side (marked as sp on main board) I think that is speed sensor, but not corresponding at any sensor. I followed track on main board under side (marked by red pen) and it arrive at point where are print s443f, but there isn't any component.
So my motor not have speed sensor?
Sorry for my bad english

 

[jonny]

Guys can help me?

 

[Rassy]

jonny, sorry I can't help you directly, but as a new kit your vendor should be able to help. Normally I would not expect the motor to be directly involved in sending a speedometer signal to the controller/display. What I would expect is for the kit to include a magnetic pick up either from one of the wheels (that's what comes with a Bafang BBS02), sort of like a regular bicycle speedometer does, or from a disk you attach to the bottom bracket. Perhaps one of these parts was missing in your kit?

Edit: That white wire on the built in controller could be for the Speedometer sense (SP) or for throttle speed (SP), I really have no idea.

 

[jonny]

Hi Rassy
Thanks for reply.
No I bought only display with controller and torque sensor.
Bafang hub motor i already has from my old kit
Vendor say me that its bafang hub motor (same model as my) have speed sensor inside.
But as also you say, white wire probably is speedometer sens, but no component on board
It impossible to talk with bafang company to ask

 

[Rassy]

I am still unable to give you any real help. When all components like that do not come as a kit (i.e. motor, controller, etc.) it can be very hard to get any support. I have tried to contact Bafang directly a couple of times in the past with no success, even the dealers seem to have trouble getting information from Bafang.

Was there a speedometer on the original bike that used that motor? You said you purchased a new controller, so are you essentially not using the internal controller, or did you purchase a new internal controller?

I had an 850c display on one of my BBS02 units once, but it is now on a friend's trike, also with a BBS02. There is an external speed sensor with a spoke magnet on the BBS02 which feeds the speed pulses to the controller and from there to the display. So I really don't know enough to figure out how your system is supposed to work. You may be able to find a good wiring diagram for your system that would help you troubleshoot the problem. Good luck, and maybe someone that is using that same system will come here and provide some good help.