Could you please follow the steps below to do it and send us a video(under 30 seconds)for our diagnosis.

1. .Use a multimeter (DC 200V gear) to verify whether the battery converter is supplying power to the controller. (Priority Inspection)

1.1 Switch on the power for both batteries.

1.2 Measure the voltage at the interface where the converter connects to the controller (ensure you do not test the wrong interface).

If there is no voltage, the converter needs to be replaced. If voltage is present, the controller needs to be replaced.https://www.youtube.com/watch?v=M2PK5dzMre4

2. Check the battery voltage. If the battery voltage is abnormal, first replace the battery top cover ; （Switch on batter power button firstly）

--H7 AWD/H9 AWD：https://www.youtube.com/watch?v=tlGVqMKlbUY

--H7 ultra/H9 ultra：https://www.youtube.com/shorts/EqMbIA9Rqdw

-The normal voltage range for a 48V battery is 40-54.6V. (Different remaining battery levels result in different voltages)

3. Use a multimeter (DC 200V gear) to Measure the voltage at the instrument cable interface on the main harness side. If there is no voltage, replace the main harness; if there is voltage, replace the dispaly.

https://www.youtube.com/watch?v=W-PuBZ5Un90

--battery：https://www.youtube.com/shorts/Dw6jiTXmKOY

1. When two batteries are present, the battery with the higher voltage will be previously used for power supply.
2. If only the front battery is needed, simply turn off the rear battery.
3. Regarding the battery energy bar, this is a normal setting and will not affect the total battery discharge.
4. Turning off the 22A battery will not affect the torque.

Friendly Reminder: If you find that you must first activate the 60Ah battery before you can use the 22A battery, it is possible that the battery converter has been wired incorrectly.

How to Correctly Install Dual Battery Converter:https://www.youtube.com/watch?v=-uN2lBAcCHk

Please follow the steps below to do it and send us a video for our diagnosis. 

1. If you have a multimeter, Please use its DC 200V gear to test the battery output voltage and the charger output voltage. （Switch on batter power button firstly）

--battery：https://www.youtube.com/watch?v=tlGVqMKlbUY

--charger : https://www.youtube.com/watch?v=f_otXtzmTUc

-The normal voltage range for a 48V battery is 40-54.6V. (Different remaining battery levels result in different voltages)

- For a 48V charger, the normal voltage should be 54.6V.

Tell us about the test results. If the battery voltage or charger voltage is abnormal, we will resend you a new one.

1. If you don't have a multimeter, proceed as follows:

- Plug the charging cable into the battery. If the charger light remains green from the beginning, the charger is faulty.

- Plug the charging cable into the battery. If the charger indicator light is red, but the battery indicator light does not light up when you long press the battery power button, then there is a problem with the battery.

If the battery, controller, and charger are all good, then the display need to be replaced.

Could you please follow the steps below to do it and send us a video(under 30 seconds)for our diagnosis.

1. If you have a multimeter, Please use its DC 200V gear to test the battery output voltage and the charger output voltage. （Switch on batter power button firstly）

--H7 AWD/H9 AWD：https://www.youtube.com/watch?v=tlGVqMKlbUY

--H7 ultra/H9 ultra : https://www.youtube.com/shorts/EqMbIA9Rqdw

--charger : https://www.youtube.com/watch?v=f_otXtzmTUc

-The normal voltage range for a 48V battery is 40-54.6V. (Different remaining battery levels result in different voltages)

- For a 48V charger, the normal voltage should be 54.6V.

Please tell us about the test results.

2. If you don't have a multimeter, proceed as follows:

- Plug the charging cable into the battery. If the charger light remains green from the beginning, the charger is faulty. If the charger is functioning properly, then the battery top cover needs to be replaced.

how to measure the voltage of 55A energy storage battery(For H7ultra/H9ultra)

1. Remove the screws on all four sides.
2. As shown in the video, disconnect the internal wiring connectors, leaving only the thinner wire connected.
3. Turn on the battery switch (display screen will not light up at this stage).
4. Set the multimeter to DC 200V and measure the voltage at the yellow discharge port (40–54.6V).

--battery : https://www.youtube.com/watch?v=tlGVqMKlbUY

the Ultra series batteries are a bit special; the inability to charge is usually related to the inverter switch. Please follow these steps to troubleshoot:

1. Check the Inverter Switch: Press the button on the battery to turn off the inverter switch, then turn the key to restore power. The yellow triangular icon should then allow for normal charging.
2. If it doesn't disappear, the battery inverter needs to be replaced.
3. If you have a multimeter, Please use its DC 200V gear to test the battery output voltage. （Switch on batter power button firstly）

--battery : https://www.youtube.com/shorts/EqMbIA9Rqdw

-The normal voltage range for a 48V battery is 40-54.6V. (Different remaining battery levels result in different voltages)

please tell us the voltage reading.

how to measure the voltage of 55A energy storage battery(For H7ultra/H9ultra)

1. Remove the screws on all four sides.
2. As shown in the video, disconnect the internal wiring connectors, leaving only the thinner wire connected.
3. Turn on the battery switch (display screen will not light up at this stage).
4. Set the multimeter to DC 200V and measure the voltage at the yellow discharge port (40–54.6V).

-Video: https://www.youtube.com/watch?v=tlGVqMKlbUY

Please click the link to see how to troubleshoot the issue.

-Video: https://www.youtube.com/shorts/Dw6jiTXmKOY

1. Use a screwdriver to disassemble the battery head.
2. Use pliers to strip the insulation from the two thin wires, then twist the two wires together.
3. Next, turn the key to the "on" position.
4. Use a multimeter to measure the voltage at the battery's discharge port.
5. If voltage is detected, replace the battery head assembly.
6. If no voltage is detected, replace the battery itself.

Please send us a video of the test results.

Press and hold the battery button until the indicator light illuminates, showing the remaining battery level. A single press will not activate the indicator light. After installing the battery into the battery compartment, turn the key to connect the power source. Then, press the power switch on the instrument panel. Next, adjust the power assistance level to 1 or higher, and twist the throttle to move forward.

If you suspect that there's the problem with the battery/charger, please follow the steps below to do it and send us a video / pictures for our diagnosis.

1. If you have a mulmeter, Please use its DC voltage 200V gear to test the battery output voltage and the charger output voltage

-battery: https://www.youtube.com/watch?v=g2ZH3OAevbE

-charger: https://www.youtube.com/watch?v=f_otXtzmTUc

--The normal voltage range for a 48V battery is 40-54.6V.

--For a 48V charger, the normal voltage should be 54.6V.

Tell us about the test results. If the battery voltage or charger voltage is abnormal, we will resend you a new one.

1. If you don't have a multimeter, proceed as follows:

--Plug the charging cable into the battery. If the charger light remains green from the beginning, the charger is faulty.

Plug the charging cable into the battery. If the charger indicator light is red, but the battery indicator light does not light up when you press the battery power button, then there is a problem with the battery.

Regarding the battery, The range of an e-bike is influenced by various factors such as environment, terrain, rider weight, and riding conditions. Especially in winter, battery life is significantly reduced. The maximum range is typically achieved when riding at a steady speed in the lowest gear (usually in eco mode), using both electric and pedal assist. This setup minimizes energy consumption, allowing for the best possible distance on a single charge.

If still encounter the issue, Could you please send us a video to show the test data of the battery output voltage when using the 200V DC voltage multimeter?

-battery: https://www.youtube.com/watch?v=g2ZH3OAevbE

-The normal voltage range for a 48V battery is 40-54.6V.

Additionally, to improve your e-bike's range:

1. Use lower assist levels: This can help conserve battery power for longer rides.
2. Maintain proper tire pressure: Well-inflated tires reduce rolling resistance.
3. Avoid excessive weight: Carrying less can help improve efficiency.
4. Plan your routes: Opt for flatter terrain when possible, as hills can drain the battery faster.

The technician reported that this type of charger has its own built-in protection device, so the voltage cannot be measured. the red light flashing, which indicates that the charger has triggered its protection mechanisms (output short-circuit protection/reverse polarity protection/output over-voltage protection/over-temperature protection).

If your charger pin is broken, please take specific photos and provide your order number to our after-sales email. If it is within the warranty period, we will resend a charger and a battery connector.

Hello, the Ultra series batteries are a bit special; the inability to charge is usually related to the inverter switch. Please follow these steps to troubleshoot:

1. Check the Inverter Switch: Press the button on the battery to turn off the inverter switch, then turn the key to restore power. The yellow triangular icon should then allow for normal charging.
2. If you have a multimeter, Please use its DC 200V gear to test the battery output voltage. （Switch on batter power button firstly）

-battery: https://www.youtube.com/shorts/EqMbIA9Rqdw

-The normal voltage range for a 48V battery is 40-54.6V. (Different remaining battery levels result in different voltages)

please tell us the voltage reading .

This is normal behavior; most e-bikes feature a delayed power-off design to allow you time to organize your belongings or check data after removing the key. Typically, the power will shut off automatically within 30 seconds to 2 minutes.

1. The power supply of the vehicle is not affected by the AC power switch. Pressing this switch or not has no effect on the power supply.
2. The AC power switch only needs to be turned on when powering 110V electrical appliances.

1. The battery is not fully seated to the bottom of the battery compartment, preventing the locking latch from engaging smoothly.
2. If the battery is properly installed but still fails to lock, please lift the battery slightly to loosen it within the guide rails of the battery compartment.

1. The abnormal instrument data may be caused by incorrect user adjustments to the instrument parameters. Please reset the instrument.
2. It's less likely due to an uncalibrated voltage or a damaged voltage detection circuit. In this case, the instrument needs to be replaced.

Blue Light — Charging

Green Light — Waiting for Connection / Fully Charged

Red Light — Charger Fault

Please record a video—less than 30 seconds in length— showing the red light flashing after the charger was connected to the battery so that I can submit a warranty claim on your behalf. Thank you.

lithium battery capacity attenuation is a normal physical phenomenon. Just like the battery life of a mobile phone will decrease after long-term use, the core reason is that the lithium ions inside the battery will gradually lose activity and wear out during the charge-discharge cycle, which leads to the reduction of storable power. This is a common feature of all lithium batteries (including those used in electric bikes, mobile phones, laptops and other devices), and it is not a product quality problem. The specific attenuation speed will be affected by factors such as usage habits, ambient temperature and charging methods.

Please fold the bike frame, connect the rear wheel motor cable connector to the rear controller connector, and turn on the power. Set the gear level to 1 or higher, then twist the throttle to check if the front wheel rotates normally. If it rotates normally, this indicates that the rear controller is functioning correctly but the motor core of the rear wheel is faulty . If front wheel also fails to rotate, this indicates that the rear controller needs to be replaced.

-https://www.youtube.com/watch?v=ZeNMYApeJ-k

-https://www.youtube.com/watch?v=dsfw18tl9G0

Headset check: Hold the front brake and gently rock the bike forward and back. Do you feel a clunk or movement between the handlebars and the frame?

Fork alignment: Stand in front of the bike and look down to see if the front wheel aligns straight with the frame. Also, from the back, check if both wheels are in a straight line.

Steerer tube check: If possible, loosen the stem and raise the fork slightly to visually inspect the steerer tube for any bending.

If the headset is loose, it might be adjustable. If the fork leg or steerer tube is bent, it may need replacement.

Please refer to the video to adjust the rear suspension spring.

-https://www.youtube.com/watch?v=J1E4Cgd7Jkc

-https://www.youtube.com/watch?v=CzYtbCh7C14

please see the attached picture to find the USB port.

Check for loose circuits. If no abnormalities are found, replace the main wiring harness and the instrument panel.

Based on the video, the display screen is flickering. This appears to be caused by an unstable power supply to the instrument cluster; either the display screen itself needs to be replaced, or the main wiring harness requires replacement.

please refer to

If you have a multimeter, Please use its DC 200V gear to Measure the voltage at the instrument cable interface on the main harness side. If there is no voltage, replace the main harness; if there is voltage, replace the instrument. (it'd be better to attach a video that )

-https://www.youtube.com/watch?v=W-PuBZ5Un90

The battery balancer may be faulty and need to be replaced.

If you have a multimeter, please use it (set to DC 200V) to check whether current is flowing through the battery balancer and if the voltage at this point is normal. (40-54.6V)

-https://www.youtube.com/watch?v=M2PK5dzMre4

If you don't have a multimeter, please disconnect the battery balancer to see if the flickering stops.

Regarding the acceleration issue, we’ve attached a video to guide you through adjusting the gear speed ratios. Please follow the instructions in the video:

Turn on the display and press both the + and - buttons simultaneously to enter the adjustment interface.

Select 02P, then short-press the i button. The lower part will flash 5-1.

Short-press the i button again to display 5-1-67, which represents the speed ratio for the first gear. Use the - button to adjust the percentage — the smaller the number, the slower the speed.

Short-press the i button again to display 5-2-75, which represents the speed ratio for the second gear. Adjust it in the same way.

After confirming the settings, short-press the i button — 02P will flash. Long-press the i button to return to the main display interface.

Press and hold the + and - buttons; the numbers on the screen will flash. Press the + button to set it to 05P, then press the i button to confirm. Next, press the + or - buttons to set the maximum speed, and finally press the i button again to save the settings.

Bluetooth:

1. click "Setting" icon on the top right
2. Roll down and find"Advanced parametersettings"
3. Enter the password "8668"

https://www.youtube.com/watch?v=zticwXQr9mI

If not work, Please try unlocking the speed via Bluetooth again using the following method:

1. Uninstall the ebike app from your phone.
2. Then scan the QR code attached to download the new app.
3. Connect the app to your phone via Bluetooth.
4. Enter the app and modify the speed parameters.

Press and hold the + and - buttons; the numbers on the screen will flash. Press the + button to set it to 05P, then press the i button to confirm. Next, press the + or - buttons to set the maximum speed, and finally press the i button again to save the settings.

1. Uninstall the App and reinstall it.
2. Restore the display to factory settings.
3. Register a new account and then reconnect the display via Bluetooth.

Please follow the steps as shown in attached picture to restore the factory : (see attached pictures)

Download :

I0S system

Search for "Yolinebike" in the Apple App Store

Android system

Scan the QR code of the image , using a mobile browser to download the "E-bike"app；

https://youtu.be/EhsgeVrExic

The following is a video link about the display unlock operation.：https://youtu.be/EhsgeVrExic?si=NZcLroe369DFOmHy

Please follow the steps to solve the problem:

1. Long press and hold minus and i key simultaneously formore than 10s (15s) to enter the background passwordinputinterface.
2. [-PP] is the background input interface. The background password is 1313.
3. Press the plus or minus key to select the parameter
4. Press i key to save the numbers and go to the next digitsetting
5. After entering the password, Enter the password and press i key to enter the displayshow interface

1. Check the controller :

Is this issue of insufficient power only occurring when climbing ? Does the same power issue occur when riding on flat terrain? If this only happens when climbing, it indicates that the controller's high current protection is automatically triggered, reducing power output. If this issue also occurs on flat surfaces, please check the controller wiring for burnt-out areas; in this case, the controller may need to be replaced.

Our motors are suitable for short climbs, but not for long climbs. This is because they have high current protection and low battery voltage protection. If the controller temperature is too high or the battery voltage is too low, the power will intelligently cut off. If the display lights up normally and no error codes appear, and the bike can be ridden normally again after a while, it indicates that the motor or controller temperature was too high, triggering the automatic protection. You can test it on a flat surface to see if it still cuts off the power. If it still cuts off the power on a flat surface, the controller needs to be replaced.

1. Check the voltage of the battery :

If you have a mulmeter, Please use its DC voltage 200V gear to test the battery output voltage. （Swtich on batter power button firstly）

battery：https://www.youtube.com/watch?v=g2ZH3OAevbE

-The normal voltage range for a 48V battery is 40-54.6V.

Press and hold the [-] button to activate walking mode

In walk boost mode, only the rear wheels turn; the front wheels do not.

Regarding kinetic energy recovery, the currently sold models do not equipped with this function. However, you can achieve energy savings by adjusting the assist level.

Turn the throttle lever and hold it. At the same time, long press the [-] button until a flashing icon appears in the lower right corner of the display; cruise control is now successfully activated. To disengage cruise control, simply squeeze the brake lever.

https://youtube.com/shorts/rAINf4xmQXU

Please check if the converter is installed incorrectly. Please refer to the attached video for reinstallation. Pay particular attention to the warning in the middle of the video: Do not connect the converter's plug to the controller port.

https://www.youtube.com/watch?v=-uN2lBAcCHk

Symptom: the rear wheel rolls forward smoothly but locks up when rolling backward. This is usually caused by a stuck hydraulic disc brake caliper (piston not retracting fully) or residual pressure in the brake line — the most common hydraulic brake issue for ebikes.！！！

Safety First (Before Any Repairs)：

• Turn off the ebike power and prop the rear wheel off the ground (use a bike stand or secure the frame safely)；
• Do NOT get any brake oil, lubricant, or grease on the brake rotor or brake pads — this will cause brake failure and require replacement parts；
• Use clean rags and isopropyl alcohol (brake cleaner) for wiping components

Step 1: Quick Brake Lever Adjustment (Simplest Fix)

1. Locate the small hex adjuster screw on your brake lever (near the handlebar pivot).
2. Turn the screw counterclockwise 1–2 full turns to release excess lever pressure and create more piston clearance.
3. Squeeze and release the lever fully 3–5 times, then test rolling the rear wheel backward.
4. If the wheel moves freely, the issue was over-tightened lever adjustment.

Step 2: Check for Stuck Caliper Pistons (Most Common Cause)

1. Loosen the caliper mounting bolts (no need to disconnect the hydraulic hose) and wipe away dust, dirt, and brake dust from the caliper body.
2. Insert a thin plastic shim (or old business card) between the brake pad and rotor to prevent pinching.
3. Gently press both caliper pistons inward with your fingers (or a soft plastic tool) — pistons should retract smoothly and evenly.
4. If a piston is stuck/unable to retract: Clean the piston surface with isopropyl alcohol, then lightly lube the piston seal with brake-specific silicone grease (do NOT over-apply).
5. Re-align the caliper, tighten mounting bolts, remove the shim, and test backward wheel movement.

Step 3: Inspect Hydraulic Hose & Leaks

1. Check the entire brake hose for kinks, crimps, or pinching (a bent hose traps pressure and prevents piston retraction).
2. Inspect hose fittings and the lever reservoir for small leaks — seepage will disrupt hydraulic pressure.
3. Straighten minor kinks gently; replace severely damaged hoses immediately.

Step 4: Bleed the Brake System (Advanced Fix)

If air is trapped in the hydraulic line, it causes uneven pressure and stuck pistons:

• Use the correct brake fluid for your model (DOT 3/4 or mineral oil — NEVER mix the two).
• Bleed air from the caliper bleed valve while squeezing the lever, top off the reservoir to the marked level.
• If you're unfamiliar with brake bleeding, we recommend taking the ebike to a certified bike repair shop to avoid damage. (Reimbursement arrangements must be negotiated with us in advance.)

If the Issue Persists

If troubleshooting doesn't resolve the lock-up, the problem may be worn piston seals, damaged caliper components, or a faulty freewheel (rare for hydraulic brake issues). Please share your ebike order number and brake system details (video) for further support.

1. please refer to the video attached to adjust the front fork shock absorption
2. Please check if the front fork/front wheel is installed incorrectly, such as if the quick-release rod is not properly installed. Please reinstall it or adjust the stem.
3. Please check if the front fork is deformed. If so, please provide relevant pictures/videos

It's normal to set the wheel diameter larger than the actual value. When the bike speed reaches the legal limit (e.g., 25 km/h), the motor must stop providing assistance. The system relies on wheel diameter data to calculate this cutoff point. If the set wheel diameter is smaller than the actual value, the system will mistakenly assume you are riding faster than you actually are, causing the motor to stop providing assistance prematurely; conversely, if the wheel diameter is set larger than the actual value, the motor's assistance cutoff speed will be delayed, allowing the motor to provide assistance for a longer period.

please refer to the steps to set the wheel diameter.

1. Check whether the ring bearing inside the motor is loose or damaged.
2. Fold the ebike, connect the front controller to the rear wheel motor cable, and twist the throttle to see if there is any abnormal noise when the rear wheel rotates.

Tutorial video

https://drive.google.com/file/d/1PC7YYI-n0tG5TAyOTt3JEI234d61aYkS/view?usp=drive_link

Cause:

The freewheel has come loose or detached and needs to be retightened.

Please follow the instructions in the accompanying video; the steps are as follows:

1. Begin by removing the chain.
2. Shift the gear selector to the 7th gear position.
3. Press the rear derailleur downward. Then, lift the chain clear of the freewheel (ensure the freewheel does not remain in contact with the chain).
4. Align the freewheel's threads with the hub and slowly rotate it to tighten. (Once the threads are properly aligned, it should screw on very easily.)
5. Once secured, reinstall the chain, placing it onto the smallest cog (the outermost ring) of the freewheel
6. Squeeze both the left and right brake levers firmly. Then, stand on the pedals and apply strong downward pressure to fully tighten the freewheel. (Three firm pedal stomps should be sufficient.)

The process is now complete.

1. Please check whether the white bushing inside the seatpost has slipped down to the bottom of the tube. If so, simply re-secure it firmly using strong adhesive.
2. Please try rotating the seatpost clamp to tighten the seatpost.

Please try loosening the seatpost clamp, then slowly insert the seat into the seatpost by rotating it left and right. If this still doesn't work, please use a file to smooth the inside of the seatpost. This phenomenon is within the reasonable production tolerance. If the above two methods still cannot solve the problem, please send a video showing the problem；

One account can bind multiple vehicles, but a vehicle that has already been bound cannot be bound to any new account.

For any apps downloaded from sources outside the phone app store, the system will automatically pop up a risk reminder. This is a normal security prompt on all mobile devices. Please rest assured that wallke e-bike APP is an official and safe application.