Thumb throttle won't stop when released

Reflector

10 W
Joined
Jun 7, 2014
Messages
80
Location
Land of The Great Grey Grasshopper
My thumb throttle (with a slight movement) will start the BBS02, but at approximately half of the lever's range of movement the motor takes over with a mind of its' own. It is as if the motor has a slight hesitation before deciding to 'go for broke'. The thumb lever moves freely but doesn't turn off the throttle when it returns to its' home position.
Luckily, my Wuxing electric clutch / kill switch does the job to stop the motor.
The electrics have never been wet and this problem appeared suddenly.
Any ideas anyone?
 

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Most likely either the sensor itself, or a magnet, has come loose inside the throttle.

Sometimes you can repair them, usually they just disintegrate further when you open them up. :(

FWIW, a broken ground wire will cause many controllers to see a throttle output voltage when none was intended, but this doesn't normally require any throttle movement first.
 
First, trace the throttle ground wire back from the connector on the controller, all the way to the throttle to make sure the cable/wire isn't damaged. Then read Tommycat's thread, or at least pay attention to the pictures to get an idea about what you'll be doing when opening it up. Try not to break off the plastic tabs. Once it's open, you can check for whatever has worked loose.

https://electricbike.com/forum/forum/kits/golden-motor-magic-pie/70584-guide-to-hall-sensor-throttle-operation-testing-and-modification
 
Thanks guys for your input; I found the original (unused) Bafang thumb throttle and tried that with the same result.
I've had a look at Tommy Cat's throttle guide and see that it is very in depth indeed and I'll dig deeper.
 
Reflector said:
I found the original (unused) Bafang thumb throttle and tried that with the same result.
Then it's unlikely to be a mechanical issue with the throttle, and more likley to be electrical.

But it could also be somethign corrupt in the settings that is causing some kind of cruise control to activate.
 
That's pretty bizarre. Never heard of that symptom before with a BBS02.
When you stop it with the brake lever switch, does it start going again when you release the brake?
 
fechter said:
That's pretty bizarre. Never heard of that symptom before with a BBS02.
When you stop it with the brake lever switch, does it start going again when you release the brake?

No, when the brake lever switch is activated the motor stops. However when the 'Big Green Button' is pressed and released, the motor hesitates and sometimes keeps on going.
 
I'd be inclined to try re-flashing the software if you can figure out what the right version is. Possibly something in the file got corrupted. I've never seen a cruise control feature on the BBSxx.
 
Not the sort of unexpected 'cruise control' I care for :shock: I had already flashed the software.
Afterthought; The BBS02 installed in my velomobile has the speedo sensor mounted at one of the front wheels. While testing throttle operation with the rear wheel on a roller (bricks as chocks in front of both front wheels) I managed to get an occasional '0x21' error and then I thought :idea: Maybe the controller is expecting speedo feedback before it can adjust the throttle limit.
Does anyone know if there is a maximum length of cable before speedo sensor data is no longer accepted by the controller?
If necessary, what I could do is cut the cable and extend it so that the pickup can be mounted on the rear wheel.
 
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