1. Introduction
This manual provides essential information for the safe and effective use of your FYIOGXG replacement battery, designed for TD Tech EP631 and EP682 devices. Please read these instructions carefully before installation and use to ensure optimal performance and longevity of your battery.
Key Features:
- Compatible with TD Tech EP631 and EP682 devices.
- Certificated with ISO9001, RoHS, and CE standards.
- Capacity: 3450mAh / 13.11Wh, Voltage: 3.8V.
- Equipped with a fully decoded chip for seamless operation.
- Built-in protection against overcharge, over-discharge, over-voltage, and short circuit.
2. Setup and Installation
Before installing the new battery, ensure your device is powered off. Carefully check the model number of your device and the part number of your original battery to confirm compatibility.

Figure 2.1: Angled view of the FYIOGXG replacement battery, highlighting the label with model and part numbers.
Installation Steps:
- Locate the battery compartment on your TD Tech EP631 or EP682 device.
- Remove the old battery, if present.
- Align the new FYIOGXG battery with the device's battery slot.
- Gently push the battery into place, ensuring the connector is properly seated and connected to your device.
- Close the battery compartment cover securely.
Numerous installation videos are available online for visual guidance if needed.
3. Operating Instructions
Initial Use and Charging:
For optimal performance, a new battery will achieve its best capacity after 2 or 3 complete charge and discharge cycles. This means fully charging the battery, using it until it's low, and then fully recharging it, repeating this process a few times.
General Usage:
- Use the battery only with compatible TD Tech EP631 and EP682 devices.
- Avoid completely draining the battery frequently, as this can reduce its overall lifespan.
- Charge the battery using the original or a high-quality, compatible charger designed for your device.
4. Maintenance and Care
Charging Recommendations:
- Do not use low-quality third-party adapter chargers, as they can shorten the battery's life and pose safety risks.
- Charge the battery in a well-ventilated area, away from direct sunlight or extreme temperatures.
- Unplug the charger once the battery is fully charged to prevent overcharging, although the battery has built-in protection.
Storage Guidelines:
- If storing the battery for an extended period, charge it to approximately 50-60% capacity.
- Store the battery in a cool, dry place, away from extreme heat or cold. Do not store above 60°C (140°F).
- Avoid storing the battery in direct sunlight or near heat sources.

Figure 4.1: General battery guidelines for safe handling and usage.
5. Troubleshooting and Safety
Safety Warnings:
- DO NOT attempt to disassemble, open, or service the battery pack.
- DO NOT crush, puncture, short external contacts, or dispose of in fire or water.
- DO NOT expose the battery to temperatures above 60°C (140°F).
- To reduce the risk of fire or burns, read all instructions in the operating guide before using the battery.
- Keep the battery out of reach of children.
Common Issues:
- Battery not charging: Ensure the charger is properly connected and functional. Check if the battery connector is securely seated in the device.
- Shortened battery life: This can be normal over time. Ensure you are following charging and maintenance guidelines. Avoid extreme temperatures during use.
- Device not powering on: Confirm the battery is correctly installed and has sufficient charge. If issues persist, consult your device's manual or contact support.
6. Product Specifications
| Specification | Value |
|---|---|
| Model Number | BTY3500LI20 |
| Compatible Devices | TD Tech EP631, EP682 |
| Battery Type | Lithium Polymer |
| Capacity | 3450mAh / 13.11Wh |
| Voltage | 3.8 Volts |
| Dimensions | 110.50 x 56.50 x 14.40mm (approximate) |
| Weight | 94.0g (approximate) |
| Reusability | Yes |
| Certifications | ISO9001, RoHS, CE |
7. Warranty Information
This FYIOGXG replacement battery comes with a 1-Year Warranty from the date of purchase. This warranty covers manufacturing defects. Please retain your proof of purchase for any warranty claims.
8. Customer Support
If you have any questions, concerns, or require assistance with your FYIOGXG battery, please do not hesitate to contact our customer support team. We aim to provide an email reply within 24 hours.
For support, please refer to the contact information provided with your purchase or on the product packaging.