Ebike kit build hub motor stutters and jerks but will not work

[Jeff151ebike]

Working on a ebike kit build and have it hooked up correctly I think. It has a 500 w motor that is 36 v. The controller says 36v dc. 22ah. I was using an extra battery I had laying around that is 36 v 8 ah. It was putting out 37 v after testing with my volt meter. My dilemma is why is the hub motor wheel just stuttering and jerking as I turn the throttle. Throttle lights are coming on. Hoping to doing an easy repair so I don’t have to open the motor. Thanks very much.

 

[Chalo]

Could be a bad Hall sensor connection, or incorrect Hall/phase wire assignment. That's the most likely thing to cause "stutters and jerks". Did your motor and controller come from the same vendor as a kit?

It could be your battery pack has a low cell group in it, that trips the LVC when there's any load. (37V is quite low state of charge for a nominally 36V battery). If the pack has been sitting around for a while, there may be one cell group that has been running the BMS all this time, and has become discharged.

 

[Jeff151ebike]

I’ll check it. Yes same vendor. And you could be right on about the battery. I have it as an extra battery for another ebike I’ve got. It has never fully charged even after the charger light has turned green. Thanks very much.

 

[Jeff151ebike]

Update.
I was leaning toward the hall sensor on the problem. I checked the connection to the controller and all seemed fine but was a slightly loose yellow wire. I decided to just cut the hall sensor wires and just connect each of the colored wires instead of the white connector they were in. To my surprise the wheel and motor took right off. So must have been something in the factory or shipping that disconnected a wire or 2 within the controller hall sensor wires and the motor hall sensor motor wires. All is well and will get to continue the build. Thanks fir your help.

 

[Chalo]

Good news. :thumb: