Bafang throttle not cutting off

Hi,

I recently bought the 52v 1000w bafang motor.

I had it briefly installed and running fine but now the throttle stays on and won't cut out when released. There is no throttle control, once it's on it stays on full. Same with pedal assist ..it will keep going until the ebrake sensor is activated.

I've tested it with another new display (750c), another cable and 2 different throttles, all known to be working .

Can anyone tell me if this points to a problem with the controller please or maybe suggest another fix?

Thanks for any advice

Mark

Most controllers have a stuck throttle safety algorithm built in. They won't allow any power until they see a zero throttle signal. That means that if you switched on with a short on the throttle wire or with a broken or stuck throttle, the bike won't ride off on its own. The only way anyting can happen after that is if you disconnected and reconnected the throttle while the controller remained switched on.

 

With this in mind, can you describe again the circumstances that make your motor go by itself? What makes it start?

Just to add to vfr400's post. Does the pedal assist problem still occur with the throttle disconnected?

Motor starts as normal with throttle or by pedalling but goes straight to full power and won't stop until brake sensor activated or power disconnected. Acts more like a switch with no off.

Yes problem persists with throttle cable disconnected. Was working fine in previous bike but problem doesn't seem related to the changeover as I've tested it with previous setup and no change. No errors showing..

What caused it to start doing that? Did you go over a big bump, drop the bike, load it into your car, fiddle with the settings, or did a ghost creep into your garage at night and cast a spell on it?

Have you got a programmimg cable to see if anything is amiss in the user adjustable settings?

 

You can also use the cable to reload the firmware into the controller. A bit more complex, but something to think about as a last resort.

What caused it to start doing that? Did you go over a big bump, drop the bike, load it into your car, fiddle with the settings, or did a ghost creep into your garage at night and cast a spell on it?

I guess if I knew the cause I wouldn't be here asking but i think the spell seems the most likely. No bumps or drops, simply a changeover to another frame.

I guess if I knew the cause I wouldn't be here asking but i think the spell seems the most likely. No bumps or drops, simply a changeover to another frame.

Hang on, it was working OK in the old frame, and one morning when you went to use it, you found it in a new frame and it didn't work anymore, but nothing could have happened to it? Are you sure about that? Do you have a brother, housemate or similar?

Have you got a programmimg cable to see if anything is amiss in the user adjustable settings?

 

You can also use the cable to reload the firmware into the controller. A bit more complex, but something to think about as a last resort

Hang on, it was working OK in the old frame, and one morning when you went to use it, you found it in a new frame and it didn't work anymore, but nothing could have happened to it? Are you sure about that? Do you have a brother, housemate or similar?

no I put it in the new frame. It wasn't dropped or anything like that but i agree it does seem like a bit of a coincidence

Any error codes showing ? at power up is the motor running flat out or creeping before you touch the pedals or throttle does the display show speed sounds like controller fault / corrupt program settings

How tight did you pull the cable-ties on the main cable up to the LCD?

N

Any error codes showing ? at power up is the motor running flat out or creeping before you touch the pedals or throttle does the display show speed sounds like controller fault / corrupt program settings

No errors codes. Motor is normal (off)at power up, once throttle or pedals are activated it is on flat out.

How tight did you pull the cable-ties on the main cable up to the LCD?

Not tight at all. Cables are dangling until I fix the problem.

Ok thanks guys for the help, especially vfr400 for pointing out that i must have changed something. I have found the problem even though it doesn't make sense to me. I adapted the original aluminum front cog to sit over the bafang cog to keep it looking original, it is just a facia with no other purpose. Somehow this is interfering with the throttle!

Hang on, it was working OK in the old frame, and one morning when you went to use it, you found it in a new frame and it didn't work anymore, but nothing could have happened to it? Are you sure about that? Do you have a brother, housemate or similar?

Thanks dude, you're right that I did change something but ruled it out completely coz it doesn't really make sense, but it did make me go back step by step and seems ok now. Not understand it doesn't feel like a proper fix but all seems good now..I tried explaining it below..

Ok thanks guys for the help, especially vfr400 for pointing out that i must have changed something. I have found the problem even though it doesn't make sense to me. I adapted the original aluminum front cog to sit over the bafang cog to keep it looking original, it is just a facia with no other purpose. Somehow this is interfering with the throttle!

So how does another chainring cause the throttle to stick..............?

Something you are not telling us here!

The original chainring and pedal is one piece where the bafang requires the chainring and crank to he separate. I attached the original to the bafang chainring turning it into one piece again.

It was purely a cosmetic mod to retain the 70s look of the bike but I can go without. Or I might modify the original even more to make them 2 pieces.

Anyway just back from very 1st test ride and it's all working very nicely. Thanks!

TBH from the original post didnt even realise it was a tandam?????

Yeah i didn't wanna confuse things more than I already had I thought the rear crank was interfering with it somehow at first but turned out to be irrelevant

TBH from the original post didnt even realise it was a tandam?????

And somewhat ironically the throttle itself IS actually now sticking haha. Got a twist replacement here to try out so all good!

If any of the drivetrain is causing the Bafang chainring to continue turning, even when the throttle is off, or pedals aren't turning, then the controller will be activated.

 

Try taking the chain off the Bafang chainring and see if the issue is solved.

Edited November 15, 20205 yr by Fordulike

If any of the drivetrain is causing the Bafang chainring to continue turning, even when the throttle is off, or pedals aren't turning, then the controller will be activated.

 

Try taking the chain off the Bafang chainring and see if the issue is solved.

Exactly what happened, I had basically joined the two together, thanks

Exactly what happened, I had basically joined the two together, thanks

Sweet, glad you got it sorted. The thing with the Bafang motor, is that the PAS sensor is part of the final drive cog, not part of the pedal axle. If any overrun causes the chainring to keep rotating, then the motor keeps going.

 

Must have been annoyingly confusing for you, when the main pedals were stationary, but the motor was still active

Sweet, glad you got it sorted. The thing with the Bafang motor, is that the PAS sensor is part of the final drive cog, not part of the pedal axle. If any overrun causes the chainring to keep rotating, then the motor keeps going.

 

Must have been annoyingly confusing for you, when the main pedals were stationary, but the motor was still active

Not only very confusing but when I tested it for the very first time it grabbed me by the arm and threw me on the ground! and I was so pleased with my mod too! Another lesson learned