Hello everyone,
I need help diagnosing a QS120 70H 72V 2000W mid-drive motor with a VOTOL EM150 controller.
The system worked correctly for several years. The original EM150 controller was later suspected of failing, so I installed another EM150 and imported the complete parameter file saved from the original working controller. I confirmed that the parameters remained saved after power cycling.
Current symptoms:
• Applying a very small amount of throttle produces one small click from the motor, but no rotation.
• The replacement controller then displays fault code 00000008 and “Motor Hall”.
• The original controller previously displayed 00000002 Overcurrent when throttle was applied, but that fault cleared after a power cycle.
• Battery voltage is approximately 81–82V on a nominal 72V system.
Hall sensor measurements:
• Hall supply between red and black is stable at approximately 5.0–5.3V.
• Black-to-green Hall signal changes voltage when the drivetrain/wheels are rotated manually.
• Black-to-blue Hall signal also changes voltage.
• Black-to-yellow remains approximately 0.01–0.06V and does not switch.
• The green and blue signals changing during the same mechanical rotation confirms that the motor rotor is being rotated.
• Continuity from the yellow signal soldering point on the Hall PCB to the controller-side connector is good.
• The Hall PCB looks clean, sealed and has no visible corrosion or burnt components.
Motor phase tests:
• Continuity exists between all three phase pairs.
• No phase wire has continuity to the motor casing.
Questions:
I have attached:
• VOTOL fault-code screenshot
• Photos of the exposed Hall PCB
• Motor identification marking
• Complete VOTOL parameter screenshots
• Photo of the motor/transmission assembly
I do not want to cut the PCB wires or disassemble the motor further before confirming that the diagnosis and test procedure are correct.
Thank you for any help.
I need help diagnosing a QS120 70H 72V 2000W mid-drive motor with a VOTOL EM150 controller.
The system worked correctly for several years. The original EM150 controller was later suspected of failing, so I installed another EM150 and imported the complete parameter file saved from the original working controller. I confirmed that the parameters remained saved after power cycling.
Current symptoms:
• Applying a very small amount of throttle produces one small click from the motor, but no rotation.
• The replacement controller then displays fault code 00000008 and “Motor Hall”.
• The original controller previously displayed 00000002 Overcurrent when throttle was applied, but that fault cleared after a power cycle.
• Battery voltage is approximately 81–82V on a nominal 72V system.
Hall sensor measurements:
• Hall supply between red and black is stable at approximately 5.0–5.3V.
• Black-to-green Hall signal changes voltage when the drivetrain/wheels are rotated manually.
• Black-to-blue Hall signal also changes voltage.
• Black-to-yellow remains approximately 0.01–0.06V and does not switch.
• The green and blue signals changing during the same mechanical rotation confirms that the motor rotor is being rotated.
• Continuity from the yellow signal soldering point on the Hall PCB to the controller-side connector is good.
• The Hall PCB looks clean, sealed and has no visible corrosion or burnt components.
Motor phase tests:
• Continuity exists between all three phase pairs.
• No phase wire has continuity to the motor casing.
Questions:
- Does the yellow signal remaining low confirm a failed yellow Hall sensor, solder joint or PCB trace?
- Could the Hall input circuit inside the VOTOL controller pull a good yellow Hall signal low?
- Could any software parameter, Hall shift angle, motor type, pole-pair setting or Hall/phase exchange setting cause the physical yellow signal to remain low?
- What is the best independent test for the Hall PCB without relying on the controller?
- Should I repeat the Hall voltage test using the original EM150 as the 5V supply/input for comparison?
- Does anyone know the correct Hall sensor part number or original replacement PCB for this QS120 motor?
- What is the correct way to remove the Hall PCB? The six wires appear to be soldered directly to it, with no removable internal connector.
I have attached:
• VOTOL fault-code screenshot
• Photos of the exposed Hall PCB
• Motor identification marking
• Complete VOTOL parameter screenshots
• Photo of the motor/transmission assembly
I do not want to cut the PCB wires or disassemble the motor further before confirming that the diagnosis and test procedure are correct.
Thank you for any help.
