Ebike Won't Stop

jfny1978

Active Member
Region
USA
I helped a friend convert a cruiser bike to an ebike with a Bafang Mid Drive kit. Occasionally his bike goes rogue and the motor won't stop moving the bike even when he stops peddling. I don't think the throttle is even installed. His brake sensors are not installed either.

Has anyone heard of this happening? Any ideas of what the cause could be?

Thanks!
 
I helped a friend convert a cruiser bike to an ebike with a Bafang Mid Drive kit. Occasionally his bike goes rogue and the motor won't stop moving the bike even when he stops peddling. I don't think the throttle is even installed. His brake sensors are not installed either.

Has anyone heard of this happening? Any ideas of what the cause could be?

Thanks!
Perhaps a short in the throttle cable/connection
If not used how was it terminated? Is it damaged or gotten wet?
I'd install the brake cut outs asap as there is no draw backs to doing so and as you can see... a bit dangerous not.
 
There's probably a lag in the Bafang motor that keeps it running a few seconds after the pedal assist senses lack of pedal motion. It can't cut off too quick or you get surging, right?

Most of us don't know much about it because we installed the brake cutoffs.
 
There's probably a lag in the Bafang motor that keeps it running a few seconds after the pedal assist senses lack of pedal motion. It can't cut off too quick or you get surging, right?

Most of us don't know much about it because we installed the brake cutoffs.
I'll find out, thanks.
 
I have Bafang ultra.
It is called motor overrun.
It is something a new ebike rider needs to know before getting on a Bafang powered ebike.
Thank you. I have never heard of that and have had no problems on my bike which has a Bafang mid-drive kit too. (Again, this post is about my friend's bike that I want to help fix for him)

What do you do when the overrun happens? Just wait for it to stop? Does using brakes with sensors stop the bike at that point?

Thanks!
 
Thank you. I have never heard of that and have had no problems on my bike which has a Bafang mid-drive kit too. (Again, this post is about my friend's bike that I want to help fix for him)

What do you do when the overrun happens? Just wait for it to stop? Does using brakes with sensors stop the bike at that point?

Thanks!
Yes, the properly installed brake sensors will cut the motor instantly.
 
Yes, the properly installed brake sensors will cut the motor instantly.
Great, I will help him get those working again. I think the problem was just that the sensors and/or magnet weren't sticking to the brake levers correctly. I guess super glue might be in order. :)
 
I’m hoping im not repeating a link here. I don’t read a couple of posters.

Much of this link was done by Sebz when i worked with him. Its far more methodical than many BBSxx suggestions by those with limited experience. Follow it and you’ll likely be golden. I still refer back to it from time to time.


not sure why Che finds it funny, I guess it’s just a teenage poke.
 
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I’m hoping im not repeating a link here. I don’t read a couple of posters.

Much of this link was done by Sebz when i worked with him. Its far more methodical than many BBSxx suggestions by those with limited experience. Follow it and you’ll likely be golden. I still refer back to it from time to time.

Thank you! Much appreciated.
 
Thank you. I have never heard of that and have had no problems on my bike which has a Bafang mid-drive kit too. (Again, this post is about my friend's bike that I want to help fix for him)

What do you do when the overrun happens? Just wait for it to stop? Does using brakes with sensors stop the bike at that point?

Thanks!
Brake sensors are easy to test. Their pretty straightforward. The pins are rather small but here’s a case again where a multimeter is critical. Cutouts are really rudimentary switches. Use your continuity setting and activate the lever with your probes on the pins. The wiring schematic should be in the link i shared.

Some versions of BBSxx firmware can be whacky when the cutouts aren’t installed. I saw multiple firmware versions over the 7 years. I have 3 different versions in my 4 personal BBSxx motors. I’m for setting up the entire system as designed first. That’s very important.

Google this phrase. Lots of decent video how toos.
test bafang brake cut out

 
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Brake sensor are easy to trst. Their pretty straightforward. The pin are rather small but here’s a case again where a multimeter is critical. Cutouts are really rudimentary switches. Use your continuity setting and activte the lever with your probes on the pins. The wiring schematic should be in the link i shared.

Some versions of BBSxx firmware can be whacky when the cutouts aren’t installed. I saw multiple firmware versions over the 7 years. I have 3 different versions in my 4 personal BBSxx motors. I’m for setting up the entire system as designed first. That’s very important.
You rock. Thanks Tom.
 
There's probably a lag in the Bafang motor that keeps it running a few seconds after the pedal assist senses lack of pedal motion. It can't cut off too quick or you get surging, right?

Most of us don't know much about it because we installed the brake cutoffs.
Harry makes a good point that didn't occur to me as I got the impression that going rogue meant it was running longer than a second or so. From what I understand the newer Bafangs can have this set a bit higher than in the past. Which particular mid drive are you talking about?
I have an older BBSO2B which has a known phenomenon that if the Pedal Assist / Stop Delay (aka motor run on) is set below 200ms the PAS works really wonky. Now 200 milliseconds isn't very long but if unexpected it can feel a bit unnatural. Honestly the only time I ever notice it is when I stop pedaling under high demand like climbing a hill. Brake cutoffs stop the motor instantly under all circumstances so it's really not an issue.
So I guess the question now is how long is it running after he stops pedaling.
 
Brake sensors are easy to test. Their pretty straightforward. The pins are rather small but here’s a case again where a multimeter is critical. Cutouts are really rudimentary switches. Use your continuity setting and activate the lever with your probes on the pins. The wiring schematic should be in the link i shared.

Some versions of BBSxx firmware can be whacky when the cutouts aren’t installed. I saw multiple firmware versions over the 7 years. I have 3 different versions in my 4 personal BBSxx motors. I’m for setting up the entire system as designed first. That’s very important.

Google this phrase. Lots of decent video how toos.
test bafang brake cut out

Santo Bafango in the House!!!
 
Harry makes a good point that didn't occur to me as I got the impression that going rogue meant it was running longer than a second or so. From what I understand the newer Bafangs can have this set a bit higher than in the past. Which particular mid drive are you talking about?
I have an older BBSO2B which has a known phenomenon that if the Pedal Assist / Stop Delay (aka motor run on) is set below 200ms the PAS works really wonky. Now 200 milliseconds isn't very long but if unexpected it can feel a bit unnatural. Honestly the only time I ever notice it is when I stop pedaling under high demand like climbing a hill. Brake cutoffs stop the motor instantly under all circumstances so it's really not an issue.
So I guess the question now is how long is it running after he stops pedaling.
I believe Harry has a motor from my days at Luna(tic).
 
sensors and/or magnet weren't sticking to the brake levers correctly. I guess super glue might be in order.
Oops missed this. I get the placement right with bits of double sided tape first. In many case high quality double sided tape can be pretty permanent.

permanent!
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I believe Harry has a motor from my days at Luna(tic).
I believe almost all of the BBSO2 suffer from the Stop Delay anomaly...
But from what I'm reading on here lately it seems all of the newer Bafangs have this set for a longer period then in the past... and perhaps longer than necessary.
I do believe that the BBSHD can have a Stop Delay of 0
Oops missed this. I get the placement right with bits of double sided tape first. In many case high quality double sided tape can be pretty permanent.

permanent!
From Amazon, $8.99$8.99 ($0.58$0.58 / Foot) One-Day &

Double Sided Tape, 3M Heavy Duty Mounting Tape, Waterproof VHB Foam Tape, for Indoor Outdoor Car LED Strip Lights, and Home Office Decor (Black,1/2 in x 15.6ft)​












From Amazon
The ultimate in double sided tape is 3M VHB
This is what auto manufacturers use to mount body side molding and shower door installers use to mount plate glass before silicone_ing in place.

 
I am taking a belated stab in the dark here. The guy ran the display wire between the motor and the BB shell and up the underside of the down tube. That is my prediction. The motor mount is shifting ever so slightly under load, pinching the throttle wires. Remember in sex education class when the guy asks a question about his 'friend's' problem?
 
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