No assist

[Juliet C]

I purchased the Bafang front hub motor kit & mini shark 48V 12.8Ah battery. I also purchased the LCD display C961 & eBrake cut off. My local bike shop installed it, and I've taken the bike back to them, but nobody seems to be able to solve the problem. I haven't actually ridden the bike that much since the install, but it stopped working after sitting in the garage for awhile. I could switch everything on but no peddle assist either through the pedals or through the lever on the handlebars. If I unplug all the connections on the bike (from the battery, at the hub, and on the central frame bar) then it usually starts working again. The bike shop owner seems to think it might be some kind of static charge build up? I did notice that when I plugged the battery into the charger I was seeing a spark between the charger and the battery, even when the charger was not plugged into the wall.

Has anyone else had a similar problem? Any advice on how to solve the issue? I'm not riding the bike because twice now it has quit on me when I was far from home . . .

 

[tomjasz]

Is there a magnet and sensor for PAS?

 

[Juliet C]

Is that this part? I notice that the little red light here is sometimes on and sometimes off, even when the peddle assist is working. The screw here is not particularly tight so I can toggle the piece with the light back and forth.

 

[tomjasz]

Yes. the red light should flash when the magnets in the wheel pass the sensor. SOME firmware will stop the motor if the PAS sensor and magnet are not functioning. Move the sensor to a position where the led doesn't flash. Will the motor run? No error codes on the display?

 

[Juliet C]

Thank you for the tip! That seems to have solved the problem. When the sensor is moved away, the pedal assist doesn't work. When it is closer, it works. No error code either way. I'm going to let it sit for a few days and see if it still runs as it seemed to not work after sitting for some period of time. Hope it was as simple as this though.

 

[Juliet C]

I'm having the same problem with my bike as before. The pedal assist stopped working yesterday. I fiddled with the magnet sensor and unplugged all the connections mentioned above. I removed the battery and charged it, but still nothing. Any ideas?

 

[tomjasz]

I'm having the same problem with my bike as before. The pedal assist stopped working yesterday. I fiddled with the magnet sensor and unplugged all the connections mentioned above. I removed the battery and charged it, but still nothing. Any ideas?

is it the type with an LED?

 

[Juliet C]

Do you mean on the magnet sensor? If so, yes, there is a small red light.

 

[AHicks]

A proper install would have involved installing new brake handles with internal switches built into them that are designed to kill the power to the motor when the brakes are engaged. If one of these switches is defective, or installed improperly, either one of them (left or right side) could cause what you describe. Thankfully, there's an easy test. Just unplug both of them. There should be a connector 12-18" from the brake handle. Disconnect them there. If your assist works with them disconnected, you've identified the problem.

Regarding that sensor in your pics above, you need to arrange that disk and sensor so there's something like a 1/8" gap between the senor and the magnet wheel for it to work.

 

[Juliet C]

This is a Dutch bike and the brakes are engaged by pushing the pedal back. There are no brakes on the handles. In this case, is the brake kill switch somewhere else?

 

[AHicks]

I was looking at this sentence in your first note -
"I also purchased the LCD display C961 & eBrake cut off."

Not familiar with how your bike might be set up at all, but an "eBrake cut off" is what I was thinking of. No idea how, or even if, it was installed, but something like that could definitely shut the power to the motor down.

 

[jkvt]

I'm a little confused as to whether or not you have a brake cutoff, but if you do, unplug it and see if the bike works. If it does, it's the brake cutoff that has an issue.

As for the PAS disc, it looks like the shop has it aligned pretty straight but if it is not and the disc is different distances from the PAS sensor as you pedal, so some of the magnets are not being read, then that could cause issues. But.. as long as some of the disc is close enough, I'd expect the PAS to feel like it's hesitating instead of not working all together although I'm not sure if some programming may be more sensitive than others.

Those discs seem to work best with three piece cranks. I've installed one on a one piece crank before, which that looks like, and it was a huge pain getting it to stay aligned well enough to consistently work. Not saying you're going to run into the same issue, but just be careful to make sure that disc stays in alignment.