Heard this noise before?

[Audisport09]

https://www.youtube.com/watch?v=TQ9BlSu_9VM

Hello, some help with my ebike would be much appreciated. I’ve got an intermittent t problem where after less than a mile of easy/hard riding the controller stops the throttle from working and starts make a clicking/ tapping noise instead. The regen, continues to work, no fault codes. I’m using QS205 and BAC8000. I’ve tested the motor phase wires and no shorts to motor axle. I’ve also tested the controller phases to positive and negative no shorts founds. Checked the throttle and it working fine. It can take anywhere from a few minutes to hours before it starts running normally again. I cannot replicate the problem from no load operation. It only happens when out riding. I’m suspecting motor, maybe burnt/shorted/ demagnetized? I don’t have another motor to test. I’ve got another controller but I’m scared that I might damage it too if the motor is at fault. That is the last resort ideally. Is there anything else I could do or test?

 

[skeetab5780]

I would test your hall sensors, it sounds like one of them is fried

or throw on a sensorless controller to test if you have one

 

[Audisport09]

If I unplug the halls the BAC8000 will throw an error. But if I switch it to sensor-less mode and it still does it.

 

[skeetab5780]

I dont know enough about the BAC8000 to help with that, someone else maybe can chime in

but when the hub makes that noise if it was a bad hall sensor you should be able to spin the wheel to a different position and it would start working again in theory. I have had hall sensors that only fail when the motor temp is very hot and then when they cool down they work again

either way testing them is easy and its 1 step in the process of elimination

 

[Audisport09]

I dont know enough about the BAC8000 to help with that, someone else maybe can chime in

but when the hub makes that noise if it was a bad hall sensor you should be able to spin the wheel to a different position and it would start working again in theory. I have had hall sensors that only fail when the motor temp is very hot and then when they cool down they work again

Thank you for taking the time to respond. That is how it started, I could peddle/push the bike along and it would work again. But now it is much worse, you have to wait several mins/hours before it works again. So you have heard this noise before? But could two sets of hall fail at the same time. Why no error code and why is regen still working? Going to look for a cheap controller to test with.

 

[larsb]

BAC8000 is a smart controller, and it has some diagnostic. It would throw a hall sensor fault if a broken one was the issue, or at least it would twitch when applying throttle. This sounds more like a short circuit somewhere.

Have you checked if the battery output is normal when it happens so that it's not undervoltage (or another fault shutdown) or something similar? What does the controller say when it happens?
Do you have any temperature limits set in controller or a temp sensor?

 

[Audisport09]

BAC8000 is a smart controller, and it has some diagnostic. It would throw a hall sensor fault if a broken one was the issue, or at least it would twitch when applying throttle. This sounds more like a short circuit somewhere.

Have you checked if the battery output is normal when it happens so that it's not undervoltage (or another fault shutdown) or something similar? What does the controller say when it happens?
Do you have any temperature limits set in controller or a temp sensor?

Right now It does not appear to be detecting anything, everything else continues to work like everything is normal. Although few months ago it did propose an error code. Hasn't come back since.


The battery is a simple lipo setup, no BMS shutdown. The motor is usually stone cold so can't be temp issue can it? I really hope it is not the controller, only had it for few months.

 

[larsb]

Then there will be loads of questions to be able to track route cause, if you are interested then describe all your parts of your system, motor/battery/controller/displays/brake switches/regen switches/etc.

How did you test for shorts? Isolation tester or just a DMM? I’ve had shorts that did not show until tested at 250V but still disturbed motor operation.

What i would try first is to bring whatever programming device you need and ride until fault happens, then readout hall sensors and throttle in program and check all diagnostics and screens in the program. Then disconnect everything not essential to your system and see if it changes anything.

Then, to track an intermittent wiring issue, try all connections when fault is there. Wiggle or disconnect/connect all wires

Then remove all voltage settings in controller like overvoltage and undervoltage, throttle limits etc. Does it change anything?

Then try (if you can) to start switching parts to see if it changes anything, (if you have an extra throttle, motor, controller, battery.)

 

[Audisport09]

Then there will be loads of questions to be able to track route cause, if you are interested then describe all your parts of your system, motor/battery/controller/displays/brake switches/regen switches/etc.

How did you test for shorts? Isolation tester or just a DMM? I’ve had shorts that did not show until tested at 250V but still disturbed motor operation.

What i would try first is to bring whatever programming device you need and ride until fault happens, then readout hall sensors and throttle in program and check all diagnostics and screens in the program. Then disconnect everything not essential to your system and see if it changes anything.

Then, to track an intermittent wiring issue, try all connections when fault is there. Wiggle or disconnect/connect all wires

Then remove all voltage settings in controller like overvoltage and undervoltage, throttle limits etc. Does it change anything?

Then try (if you can) to start switching parts to see if it changes anything, (if you have an extra throttle, motor, controller, battery.)

Thank you, I will give that a try.
Simple set up.
Motor: QS205
Battery: 18s lipo
Controller: BAC8000
Displays: None
Brake switches: None
Regen switches: Throttle variable regen, never fails to work.

I’m using the DMM to measure wiring shorts between phase to motor and frame continuity. I have not tested halls continuity to phase and frame. They shouldn't be any right? The joys of ebiking…

 

[larsb]

My first try with your system (which is nice and simple ) is to remove the regen throttle and see if it changes anything.
The problem could be short circuit in the regen, either activating regen/stopping drive or making the controller +5V output dive, causing malfunction.

 

[Audisport09]

My first try with your system (which is nice and simple ) is to remove the regen throttle and see if it changes anything.
The problem could be short circuit in the regen, either activating regen/stopping drive or making the controller +5V output dive, causing malfunction.

Yes good shout because they are sharing ground and power. I've decided to order new motor, so bike is in bits.