BBS02 cutting power constantly

Hi everyone!

I have been a happy owner of a bbs02 36v with karl's settings.
The motor has around 2000 miles on it. Mostly short city rides as a dd. Checked the engine temps after every ride and never seemed uncomfortably hot (not a hot climate either).
For the last few days when riding in any power setting 1-9 it gives you between 1-10 seconds of power followed by 1-10 seconds of "silence" while pedalling constantly. I am not reaching the cut off speed either.
About my setup : 10s lipo fully balace charged every time with good IR. Never connected the throttle only pas. No shift sensor or brake sensors. All cables are in good condition and so are the connectors too (nothing comes loose). I get the same power on/off intervals with a charged, half charger battery and even on a different pack. The On/off intervals hapen at every speed.
I have been playing with the settings of the controller ever since first noticing the problem, but didn't get any better.

Only things I can think of are the controller , clutch or motor.

Any ideas are welcome!

That's pretty strange. It doesn't sound like the motor or clutch.

Does anything unusual show up on the display?
Does the speed display properly?
Did you try testing with the wheel off the ground?

fechter said:

That's pretty strange. It doesn't sound like the motor or clutch.

Does anything unusual show up on the display?
Does the speed display properly?
Did you try testing with the wheel off the ground?

Click to expand...

Display is the same as every other days for the last year. Speed is shown constantly.
Speed sensor is blinking forward and stays on when reversing.
Will try on a stand.

fatal14 said:

fechter said:

That's pretty strange. It doesn't sound like the motor or clutch.

Does anything unusual show up on the display?
Does the speed display properly?
Did you try testing with the wheel off the ground?

Click to expand...

Display is the same as every other days for the last year. Speed is shown constantly.
Speed sensor is blinking forward and stays on when reversing.
Will try on a stand.

Click to expand...

Had a ride on the streets did the same thing.
After the ride I put it on a work stand. I turned the pedal and let it pedal itself.
The power went on and off about half as frequently as when wheels are touching the ground and have resistance.
I also tried pedaling at a high rpm with my arms while the bike is in the air.
The on and off action happened even less frequenty then when letting it pedal itself.
However it still hapens frequently enough to be annoying.

Still sounds pretty strange. I'd suspect the PAS sensor at this point.

Can you run it with throttle only and no pedaling? That would be a way to test downstream of the PAS sensor.

Another thing to try would be to open the controller side of the motor and unplug and re-plug the PAS connector a few times.

fechter said:

Still sounds pretty strange. I'd suspect the PAS sensor at this point.

Can you run it with throttle only and no pedaling? That would be a way to test downstream of the PAS sensor.

Another thing to try would be to open the controller side of the motor and unplug and re-plug the PAS connector a few times.

Click to expand...

I ran it with the throttle only.

70% of the time it gave a 21H error so the speed reading and shuts off in a few seconds.

30% of the time it showed the speed.

It only started showing speed after restarting the controller.

However when there was no speed reading with throttle only and you start pedaling if shows the current speed.

Very strange.

It would be good to measure the 5v going to the sensors, but not so easy to do.

fechter said:

Very strange.

It would be good to measure the 5v going to the sensors, but not so easy to do.

Click to expand...

5V going to the speed sensor and other non-enclosed itemes or you mainly mean the pas sensor inside?

fatal14 said:

5V going to the speed sensor and other non-enclosed itemes or you mainly mean the pas sensor inside?

Click to expand...

Any of them that come from the controller. They all run off the same voltage regulator. The idea is to see if you have a bad sensor or a bad controller. If the voltage is abnormally low, unplug sensors (including motor halls) one at a time and see if any make it go back to normal.