Bafang Speed Sensor Issue

[Cpop]

Hello from LA! Fairly amateur eBike guy here, looking for some help.

I just replaced my old Bafang with a new one (M625). The old one I had bought used; there was no speed sensor but it ran anyway.

The new M625 has an issue with the speed sensor. When I start riding, it works for a few seconds, and then spikes to 99.9 km/h and shuts the motor down. I have to stop and wait for the speed to reset to 0.0, then when I start again the same thing happens.

The seller is sending me a new speed sensor, but it takes time. In the meantime: is this something anyone else has encountered? Any thoughts on what the issue might be?

I've experimented with different distances between the sensor and the spokes, but it doesn't fix the issue.

Thanks, all!

 

[Cpop]

Update for future reference: the new speed sensor has the same issue; I believe it's a problem with the computer.

 

[tomjasz]

Does the led flag when the magnet passes? Any error codes?

 

[FR75018]

Hi from France.
I had a similar issue with the speed sensor on a new m625 (ordered last summer) . The meter went directly to 50kmh on the first kick of pedal... The chinese seller sent me another one in september 2021(I had to wait almost two months, and I became very worried about this seller and new motor model). Since then the new sensor is working properly, and I drove almost 4200km with my self made ebike....

 

[tomjasz]

I ALWAYS have a spare sensor. One failed this week. Fixed in minutes.

 

[FR75018]

yes good idea, Im going to get one

 

[tomjasz]

yes good idea, Im going to get one

Magnet too!