Q75 - loud(!) squealing noise with acceleration

[A..dam]

What it is, how to stop it and how bad it is for the motor/gears?
Gentle throttle use does not elicit that noise.
Initially, I thought that the axle spins in the dropout, but anti-rotation washers are installed correctly. See photo...

My system
Q 75 36 V, 201 rpm, 20 inch front
Controller Torque Simulation Square Wave S06P
Display/Computer S-LCD5
Half-Twist Throttle, # 611 PAS Ten Poles #579, Speed Sensor #550, #s from BMSB site
P - parameters: P1=214, P2=1, P3=1, P4=0, P5=12
C - parameters were left at factory default settings
P.S. ANY Idea what to input for C1, C2, C3 and C5???
Thank. A..dam

 

[d8veh]

I had the same with mine. It seemed to lose sync at full power in a certain speed range. I changed the P1 setting, which more or less solved it, but I can't remember what settings I used. It might have been 128 because I wasn't sure about the 13.4 reduction ratio. I think I took a guess at 8. Try 192 too and let us know which is best.

 

[A..dam]

If I have your attention d8veh, what about C1, C2, C3 and ESPECIALLY C5?
According to the Pythia like manual for LCD-3/5, C5 has something to do with the current going to the motor.
Q75 Motor comes in 201 and 328 rpm BUT the only one reduction ratio is listed.
So the wiring must be different for each speed AND gears would be identical.
IF wiring is the same and gears are different, reduction of 13.4 for 328 would mean a reduction ratio 328/201x13.4 for 201 rpm.
But then P1 range would be too small as it max out at 255.
Any idea where to get full specs of the motor? Who makes it?
In any case, the very reason I got 201 rpm for 20 inch is the hill climbing ability at full throttle.
I will try testing on Friday...
Cheers, A

 

[d8veh]

CI is for the type of magnet disc you have on the PAS. C1=0 always works, but you might have to flip the disc to get it to work in the right direction. I guess something is optimised if you have an 8 or 12 magnet disc and the correct setting for it, but it's not critical.

I've no idea what C2 does , and what the seven settings are for, so C2=0 is correct for normal operation.

C3 is the start up PAS level. I have mine set to 3 because that's the power I use most of the time.

C4 should be zero for normal throttle operation

C5 can have a small effect on maximum current. Things get complicated here because different controllers have different software, so the same setting could increase or decrease the current. I'd leave it at C5=0, which allows the max current written on the controller's label.

 

[A..dam]

Lowering P1 from 214 to about 190 range reduces incidence of this HORRIBLY LOUD (passers-by get startled by it) squeal by ~50% only.
Further lowering of P1, especially past 160, results in dramatic reduction of motor power.
So, it appears that S06P is not compatible - despite BMSB saying so - with Q75!!!
BMSB lists another controller LSW-675 plus LCD for 85$.
https://bmsbattery.com/ebike-kit/543-36v250w-lsw-675-sine-wave-controller-with-lcd-ebike-kit.html
Will it solve the problem?
Also I cannot access C parameters my LCD-5, maybe this controller does not support those.
Anybody knows about this issue?
The reason why C parameters might be important is that manual for LCD-3, found on BMSB site (which is supposed to be similar to LCD-5) has C14 parameter for fine tuning of power assist for PAS sensor.
Even at lowest setting my PAS / LCD-5 provides too much assistance.

 

[d8veh]

After some experiments, the problem was solved on mine, when I set P1 to 160. That might not be the ideal setting, but it works.

 

[A..dam]

Reducing the P1 lowers the power by ~10-15% (my estimate). Also, the maximum speed, throttle only, dropped from 21.5 to 19 km/h.
Considering low power of the motor such drop is not acceptable to me.

 

[mountain biker]

hey what voltage q75 you using and what battery volt you using. how many amps is maximum your putting in this hub?

 

[A..dam]

36V nominal, did not measure the A, have the power, V&A meter but do not want to change the wiring, YET ;-(

Also, I have noticed that frequency of that crappy noise diminished when my battery voltage dropped from 41V to 38.5.
The voltage of the battery was measured with 2 research grade meters, without the load.
So, I wanted to top up battery to test the hypothesis that diminishing power reduces the sound, but the battery will not accept top-up charge, see my recent post...
Will post update when battery voltage drops to ~36V...
Cheers, A..dam

 

[d8veh]

P1 must have something to do with the timing. Mine makes plenty of power and runs smooth with P1=160. I chose 160 at random and it worked. All you need to do is keep trying different values until you get it how you want. I have exactly the same battery, controller and motor as you.

 

[A..dam]

@d8veh
What LCD do you have?
I have LCD-5 and my P parameters are in the first post.
Cannot input C parameters, do you know if LCD-5 will accept C parameters?
Maybe this is the difference between our results

 

[avandalen]

I have an article on my website about the S06P squealing noise problem with a video:
S06P / S-KU63 controller