Important to know about the Qmwheel V20 Pro
- The V20 Pro has the H6C display with NFC and buttons.
- The V20 Pro wiring harness is the same as that of the V20 and S20 Pro.
- The 2024-2025 V20 Pro charges with a 3-pin charger, the same as the S20.
- The motor with the black connector on the V20 Pro is the same as that of the Ouxi V8 and H9 (2022-2024) and the S20 Pro.
That is why we always ask for the year of manufacture or a photo of the connector: this way you can be sure that the part fits.
Qmwheel V20 Pro does not turn on
You press the power button and nothing happens: no display, no light. Usually, the problem is with the power supply, and often it is easier to solve than you think.
Battery empty or in deep sleep
A battery that has not been charged for a long time can shut itself off. Charge it fully for at least a few hours. View batteries.
Battery not properly placed or lock turned off
Remove the battery and click it back into place. Check if the battery lock is set to "on" and if the contact points are clean. View battery locks.
Charger or charging port defective
Is the light on the charger not lit or does it stay green while the battery is empty? Then the charger could be the problem. The 2024-2025 V20 Pro charges with a 3-pin charger, the same as the S20. View chargers.
Loose connector at the handlebars
Check the connector between the display and wiring harness. Moisture or a partially loose connector is a common cause. View wiring harnesses for the Qmwheel V20 Pro.
Display or controller defective
Does the battery work (on another bike or meter) but everything stays off? Then the display or the controller is often the culprit. The V20 Pro has the H6C display with NFC and buttons. View displays for the Qmwheel V20 Pro.
Qmwheel V20 Pro cuts out while riding
The bike suddenly cuts out, often when hitting a bump, going uphill, or in wet weather, and sometimes works again afterwards. Such an intermittent fault almost always has an electrical cause.
Poor battery contact
Does the battery rattle in the holder? Then it temporarily loses contact when hitting a bump. A worn battery holder or dirty contacts are the cause. View battery locks.
Loose or damp connector
The connectors at the handlebars and the motor connector are particularly sensitive. A thin layer of contact grease prevents oxidation. View wiring harnesses for the Qmwheel V20 Pro.
Battery voltage drops under load
An older battery still shows a charge, but drops as soon as you demand a lot (accelerating, going uphill). The bike then switches off. View batteries.
Brake sensor stays engaged
If the controller thinks you are braking, the assistance will cut out. Check if both brake levers spring back properly. View brakes and brake sensors.
Controller overheated or defective
Does the bike cut out especially after prolonged heavy use? Then the controller may be overheated or defective. The V20 Pro wiring harness is the same as that of the V20 and S20 Pro. View controllers.
Qmwheel V20 Pro pedal assistance does not work
The display works, maybe the throttle too, but when you pedal you get no assistance. In most cases, it is due to the pedal sensor or a sensor that blocks the assistance.
Assistance level set to 0
Sounds simple, but first check if the assistance on the display is set higher than 0.
Pedal sensor or magnet ring
The pedal sensor measures whether you are pedaling. If the magnet ring is crooked, dirty, or the sensor is broken, you will get no assistance. The V20 Pro pedal sensor is located under the battery or under the seat, depending on the version. View pedal sensors for the Qmwheel V20 Pro.
Pedal sensor intermediate cable
The cable between the controller and pedal sensor is located low near the pedal crank and is easily damaged. View wiring harnesses for the Qmwheel V20 Pro.
Brake sensor sends signal
A brake sensor that stays engaged switches off the assistance. Squeeze both brakes firmly a few times and release. View brakes and brake sensors.
Controller
If no sensor works anymore, the controller may be defective. The V20 Pro wiring harness is the same as that of the V20 and S20 Pro. View controllers.
Qmwheel V20 Pro display: does nothing or shows an error code
The display stays black, turns on and off, or shows an error code. The display is where the bike shows that something is wrong, but the cause is not always in the display itself.
Error code on the display
An error code is a clue, not a diagnosis. The meaning varies per display and controller. View our explanation of error codes and send a photo of the display via WhatsApp if in doubt.
Display connector or cable
A damp or damaged display connector or wiring harness often causes communication errors. The pedal sensor, the pedal sensor intermediate cable, the display or the controller can also be the cause. Disconnect the connector, dry it and connect it firmly again. View wiring harnesses for the Qmwheel V20 Pro.
Defective display
The V20 Pro has the H6C display with NFC and buttons. View displays for the Qmwheel V20 Pro.
Battery and controller
If the display does nothing at all, first check the battery (see "does not turn on"). If it shows an error code about the motor or sensors, the fault is often in the controller or wiring. An undervoltage error code is caused by an empty battery, a loose or broken intermediate cable from the battery to the controller, or a defective battery. The V20 Pro wiring harness is the same as that of the V20 and S20 Pro. View controllers.
Qmwheel V20 Pro motor makes noise or does not pull
A rattling, grinding or slipping noise from the rear wheel, or a motor that hums but does not pull. In a hub motor, this usually indicates worn gears or bearings.
Worn motor gears
Hub motors contain nylon gears that wear out over time. The motor then makes noise or slips when accelerating. View motor gears.
Bearings or loose axle
A loose axle nut or worn bearing causes play and noise. Check if the axle nuts are properly tightened. View wheels.
Motor connector or motor cable
A damaged motor cable causes jerky riding. The V20 Pro motor with the black connector is the same as that of the Ouxi V8 and H9 (2022-2024) and the S20 Pro. View motors.
Defective motor
If the motor itself is broken, a complete motor or rim with motor is often the fastest solution. View motors.
Qmwheel V20 Pro battery does not charge
You put the battery on the charger, but it does not get fully charged, or the light on the charger does something different than normal. Start with the charger: that is often the cheapest solution.
Defective charger or wrong charger
Check if the light on the charger turns red during charging. The 2024-2025 V20 Pro charges with a 3-pin charger, the same as the S20. View chargers.
Charging port dirty or damaged
Look into the charging port on the battery: dirt, bent pins or corrosion cause poor contact. View batteries.
Battery in deep discharge
If the battery has been empty for months, the protection (BMS) may block charging. Have it tested before you buy a new one. View batteries.
Battery at the end of its life
After many charge cycles, the capacity decreases. If it still gets fully charged but empties quickly again, replacement is often necessary. Only use a charger with the correct 3-pin connector. View batteries.
How to deal with a fault
- Start simple: fully charge the battery, replace the battery, check all connectors at the handlebars.
- Look at the display: note any error code or take a photo.
- Send us a photo of the display, the connector or the part via WhatsApp. We will tell you which part you need.
- Do it yourself or have it done: order the part, or make an appointment in The Hague or Zoetermeer. Often your bike is ready the same day.
Never work on the electronics while the battery is in the bike, and never open a battery yourself. Lithium batteries can be dangerous if damaged.
Parts for the Qmwheel V20 Pro
View all parts for the Qmwheel V20 Pro, or search per part: controllers, displays, batteries, pedal sensors, motors, wiring harnesses.
Frequently asked questions
Can you repair my Qmwheel V20 Pro?
Yes. In our workshops in The Hague and Zoetermeer we repair the Qmwheel V20 Pro, often the same day. Plan via make an appointment and see the price immediately.
What does the error code on my display mean?
That varies per display and controller. Read our explanation of error codes or send a photo via WhatsApp.
How do I know which part I need?
Look at the year of manufacture, the color of the motor connector and the number of pins. Or send a photo, then we will find it out.