Bafang Ultra Controller Swap

[greeno]

Hey gents I just swapped out a controller for a buddy last week and ran into an issue maybe everyone isn’t aware of.
His motor was a UART version and when I installed the new controller it wouldn’t operate correctly.
Then I remembered I had previously purchased a couple of years ago a Bafang C961 Display to calibrate controller swaps.
So I plugged in the display, turned it on, put the power level ant least to1 as 0 won’t work, and then hold down the power/minus buttons at the same time to get it to the calibration mode.
The display should read “0” and an error code of 40 should be present.
After a few seconds the motor should start rotating for a few seconds and when calibrated correctly the final error code should show 44. Which means your good to go.

So I thought I was set only to find the motor would only operate up to about 16mph.

So…..

He was running the Bafang 750c display so I opened up the settings window and checked the wheel size and that was correct.
So then I went into the advanced settings and checked the speed limet and it was set to 25kph so I raised that up to 99kph and all was good.

One last note.
When adjusting the controllers “Throttle” settings for the “Speed Limet” I ended up setting that value to “ By Display Command” which was set so high he would never be able to achieve it if he tried but if he ever swapped out that display for another one and didn’t reset the default setting of 25kph he would have the restriction again when riding.

Just a little info for anyone if they need it.

 

[Gionnirocket]

...and for those of us who need pictures with our instructions

 

[smorgasbord]

It's also important to note that both the display and the Bafang controller have their own independent settings for wheel diameter/circumference and speed limits.

For Bafang (in the Basic tab), the Wheel Diameter works with the number of magnets you have (set via Speed Meter Signal setting) to know the bike's speed, which determines which Torque Tab's SPDxx column is being used. And there's also the Bafang Basic Tab's "Limited Speed(%)" settings, which I haven't used much so don't know how they work.

For the Display, the wheel size/diameter/circumference varies with the display manufacturer/model and mostly affects what you see on the display, but as you found out, the Max Speed (some have road/offroad or sport/eco) apparently can also have the display tell the controller to stop applying power. I believe (but have not confirmed) that this calculation is done in the display itself.