1. Introduction
Thank you for choosing the MEROCA N20B Smart Bicycle Brake Light. This device is designed to enhance your cycling safety with its intelligent sensing capabilities, multiple lighting modes, and robust IPX5 waterproof rating. This manual provides essential information for the proper setup, operation, and maintenance of your new bicycle light.
2. Package Contents
Please check the box for the following items:
- MEROCA N20B Smart Bicycle Brake Light (x1)
- Cable Tie (x1)
- Mounting Bracket (x1)
- USB Charging Cable (x1)
- User Manual (x1)

3. Specifications
| Feature | Specification |
|---|---|
| Brand | MEROCA |
| Model | N20B |
| Material | Aluminum alloy / ABS+PC |
| Battery Capacity | 420mAh |
| Waterproof Level | IPX5 |
| Intelligent Sensing | Yes |
| Support Dimmer | Single File |
| Type | Tail Light |
| Certification | CE |
| Power Supply | Battery |
| Mounting Placement | Seatpost |
| Charging Time | 1 hour 40 minutes |
| High Brightness (80 lumens) | Approx. 3 hours |
| Medium Brightness (65 lumens) | Approx. 6 hours |
| Breathing Light (50 lumens) | Approx. 10.5 hours |
| Comet Flashes (50 lumens) | Approx. 11.8 hours |
| Hybrid Flashes (50 lumens) | Approx. 14.5 hours |
| Energy Saving Flashing (40 lumens) | Approx. 20.5 hours |
4. Setup and Installation
The MEROCA N20B supports two primary installation methods: on the saddle or on the seat tube. Choose the method that best suits your bicycle and preference for optimal visibility.
4.1 Mounting on Seatpost
- Attach the rubber strap of the mounting bracket around your bicycle's seatpost.
- Secure the strap tightly to prevent movement.
- Slide the MEROCA N20B light onto the bracket until it clicks into place.
4.2 Mounting under Saddle
- Use the provided cable tie to secure the mounting bracket to the rails under your bicycle saddle.
- Ensure the bracket is stable and facing directly backward.
- Slide the MEROCA N20B light onto the bracket until it clicks into place.

5. Charging the Device
The MEROCA N20B is equipped with a 420mAh rechargeable battery. To charge the device:
- Locate the USB charging port on the light.
- Connect the provided USB charging cable to the light and to a standard USB power source (e.g., computer, wall adapter).
- The indicator light will show charging status (typically red for charging, green/off for fully charged).
- A full charge takes approximately 1 hour and 40 minutes.

6. Operation
The MEROCA N20B features both automatic and manual operation modes, along with six distinct lighting patterns.
6.1 Switching Modes
Double-click the power button to switch between automatic mode and manual mode.
6.2 Automatic Mode
In automatic mode, the light utilizes intelligent sensing:
- The light will automatically turn off after 30 seconds of inactivity (no motion detected).
- It will automatically turn on when motion is detected, ensuring you are visible when you start riding.
- The light also features smart brake sensing, increasing brightness when braking to alert traffic behind you.
6.3 Manual Mode and Lighting Patterns
In manual mode, you can cycle through the six lighting patterns by single-clicking the power button:
- High Brightness: 80 lumens (approx. 3 hours runtime)
- Medium Brightness: 65 lumens (approx. 6 hours runtime)
- Breathing Light: 50 lumens (approx. 10.5 hours runtime)
- Comet Flashes: 50 lumens (approx. 11.8 hours runtime)
- Hybrid Flashes: 50 lumens (approx. 14.5 hours runtime)
- Energy Saving Flashing: 40 lumens (approx. 20.5 hours runtime)


7. Maintenance
To ensure the longevity and optimal performance of your MEROCA N20B Smart Bicycle Brake Light, follow these maintenance guidelines:
- Cleaning: Wipe the light with a soft, damp cloth to remove dirt and dust. Avoid using harsh chemicals or abrasive materials.
- Water Resistance: The light is IPX5 waterproof, meaning it is protected against low-pressure water jets from any direction. However, avoid submerging it in water. Ensure the USB charging port cover is securely closed when not charging to maintain water resistance.
- Storage: Store the light in a cool, dry place when not in use. Avoid prolonged exposure to direct sunlight or extreme temperatures.
- Battery Care: For best battery life, avoid completely draining the battery frequently. Charge it regularly, especially if storing for extended periods.

8. Troubleshooting
If you encounter issues with your MEROCA N20B light, try the following:
- Light not turning on: Ensure the battery is charged. Connect it to a power source using the USB cable.
- Intelligent sensing not working: Double-check that the light is in automatic mode. Ensure there is sufficient movement to trigger the sensor.
- Light not holding charge: Ensure the charging cable is properly connected and the power source is functional. If issues persist, the battery may need servicing.
9. User Tips
- Always ensure your light is fully charged before embarking on long rides, especially at night.
- Regularly check the mounting bracket to ensure it is securely attached to your bicycle.
- Familiarize yourself with the different lighting modes and choose the most appropriate one for your riding conditions to maximize visibility and battery life.
- In urban environments, flashing modes can often provide better visibility than a steady beam.
10. Warranty and Support
For any questions, technical support, or warranty claims, please contact the MEROCA Official Store directly through the platform where you purchased the product. Please retain your proof of purchase for warranty purposes.