Battery for Lenovo electronic devices FRU04W4240 — RTC replacement battery

Replacement RTC battery FRU04W4240 for Lenovo electronic devices is a compact backup power cell designed to maintain the real-time clock and preserve BIOS/UEFI settings when the main power source is removed. Intended for compatible Lenovo laptops and motherboards that accept this FRU model, the battery restores accurate timekeeping and helps retain system configuration data such as boot order, hardware settings, and firmware parameters during power-off periods.

Advantages

This RTC replacement battery provides long-term standby power in a small form factor suitable for laptop and motherboard RTC circuits. It retains CMOS/BIOS settings reliably, reducing the need to reconfigure system parameters after battery removal or extended power outages. The compact design facilitates straightforward installation in compatible devices and minimizes space usage on the motherboard. Use of an OEM-compatible RTC cell ensures electrical characteristics appropriate for Lenovo systems that require this form factor.

Suitable for

• Restoring accurate timekeeping on Lenovo laptops and motherboards that use the same FRU-compatible RTC cell
• Preserving BIOS/UEFI settings and CMOS configuration when the main battery is disconnected
• Replacing a depleted RTC battery to prevent loss of system clock and configuration
• Repair and maintenance tasks on compatible Lenovo models where the RTC cell is user-replaceable

Key specifications

• Function: RTC backup power for real-time clock and CMOS/BIOS memory retention
• Form factor: compact coin-style replacement cell suitable for laptop/motherboard RTC holders
• Compatibility: designed for Lenovo devices that accept this specific FRU-compatible RTC cell
• Typical service: maintains clock and BIOS settings during main power removal or battery replacement

How to use

Power down the device and disconnect it from mains power. If accessible, remove the main internal battery and ground yourself to avoid electrostatic discharge. Locate the RTC battery on the motherboard or in the laptop compartment and carefully note the orientation of the existing cell. Gently remove the depleted battery from its holder and insert the replacement with the same polarity and orientation. Reassemble the device, reconnect main power and batteries, then power on and check system time and BIOS/UEFI settings; adjust if necessary.

Recommendations

Replace the RTC battery only in compatible Lenovo models and observe static-safe handling. Verify device documentation or service manual for specific replacement instructions and battery orientation. After replacement, enter BIOS/UEFI setup to confirm date, time, and configuration values are correct and update if required.