Sabvoton 96120 SVMC not reading proper RPM forwards, but reading proper RPM backwards.

[Marco Milano]

My new Sabvoton 96120 SVMC controller is not showing the correct RPM (I get 65000+) when my even newer QS273 hub motor rotates forwards (motor rotation parameter set to 1).

It does show the correct (apparently) RPM when changing the motor rotation parameter to 0, but the motor spins backwards.

I am just slightly turning the throttle and the wheel is not touching the ground.

The speed displayed on the LCD display is accurate, so “pole pair parameter” is correctly set to 16 for my QS273 motor.

Same thing happens when connecting to my laptop computer through the USB cable while turning wheel by hand, as for some reason throttle becomes inoperative while the controller is connected to the computer. I imagine this is a safety feature to avoid inadvertently pulling a computer by the USB cable if the wheel is not off the ground.

Anyone has an idea about what could be causing this problem?

Thank you for your attention and patience.

 

[amberwolf]

Is that the same issue from here?

MQCON app showing funny rpm value

Hello smart people, thank you for accepting me. I need to know if anyone has had problems with the MQCON phone application not showing the correct RPM value when connected via Bluetooth to a Sabvoton controller. I have a 96120 SVMC Sabvoton controller running a QS273 hub motor. Everything is...

endless-sphere.com

 

[Marco Milano]

Sort of, but brand new motor and brand new controller.

Old motor had 35000 km on it and I thought I would replace it with a new one so I could take the old one apart and check hall sensors, bearings etc. etc. I thought insulation problems had arisen that would give that strange RPM reading. I read about cheap wires losing their insulation over time.

But even with a brand new motor that strange RPM reading comes out.

In addition I noticed that reversing motor rotation on the new motor the RPM looks good, which is very frustrating. Did not test that on the old motor.

I managed to connect the bike to my laptop computer, and the RPM behaves the same odd way. I was thinking the phone app might have some problems with the software, as I am using an old iPhone7 to connect with the controller.
I had to spin the wheel by hand as the throttle becomes inoperative when the bike is connected to the computer through the USB cable.

Unfortunately also a new, recently purchased and constantly updated laptop computer shows the same RPM discrepancy.

Got in contact with QS Motor, Siaecosys, AliBaba, AliExpress but got only evasive answers and not even from all of them.

So I posted on ES again to see if someone had the same issue and solved it somehow.
Is that the same issue from here?

MQCON app showing funny rpm value

Hello smart people, thank you for accepting me. I need to know if anyone has had problems with the MQCON phone application not showing the correct RPM value when connected via Bluetooth to a Sabvoton controller. I have a 96120 SVMC Sabvoton controller running a QS273 hub motor. Everything is...

endless-sphere.com

 

[Marco Milano]

Update on trouble shooting the problem.

I replaced the 4 year old CT-22 display (I used it for 36000 km) on my bike.
I installed a brand new CT-22 display thinking that maybe the old, well used one was generating some strange signal, confusing the controller through the hall meter wire.
This was in fact a far fetched theory, as the speedometer, odometer, battery voltage bars and even the clock were working perfectly.
Only a couple of the backlighting LEDS were flickering every now and then when going over bumps and potholes.

The RPM through the MQCON app and Bluetooth now is shown as 0 in the forwards motor rotation direction.
The RPM value is shown properly when motor turns backwards.

If I connect my computer to the controller:
RPM is shown properly BUT with a - (negative) sign in front of the displayed value when wheel is turning forwards.
The RPM value is correct when the wheel is turning backwards.

Could that negative sign somehow generated by the Sabvoton 96120 in front of the RPM reading cause the MQCON App to show a 0 RPM reading on my phone through the Bluetooth connection?

Is anybody else having this problem?

 

[Marco Milano]

After riding the bike for 100km at e-bicycle legal speeds, the bike suddenly stopped, and my Sabvoton 96120 SVMC controller entered a “restart” condition.

Is there a way to get out of this situation and make the controller work again?