Battery Lenovo RTC Battery 04W4118 FRU04W4118 — replacement internal RTC/CMOS battery for Lenovo devices

Replacement internal RTC/CMOS battery Lenovo RTC Battery 04W4118 (FRU04W4118) is a compact coin-cell module designed to preserve the real-time clock and CMOS settings on compatible Lenovo motherboards. It is intended for situations where the original backup battery has depleted or when performing motherboard maintenance, ensuring the system retains BIOS configuration, keeps accurate time, and boots without prompting for setup after power loss.

Advantages

This replacement RTC battery provides stable voltage for the motherboard clock and CMOS memory, helping to prevent loss of BIOS settings and system time. Its compact form factor allows straightforward installation within compatible Lenovo devices, and it is designed to deliver consistent performance comparable to the original internal backup cell. Using a proper replacement reduces the risk of incorrect system time, BIOS errors at startup, or failed hardware configuration detection.

Suitable for

• Lenovo laptops and desktops that use an internal coin-cell RTC/CMOS backup battery
• Motherboard repairs or replacements where the original battery is removed or discharged
• System maintenance tasks requiring BIOS configuration retention and accurate RTC

Key specifications

• Form factor: compact internal coin-cell module for motherboard installation
• Function: real-time clock (RTC) backup and CMOS memory power
• Compatibility: designed for use in compatible Lenovo devices requiring an internal RTC/CMOS battery
• Mounting: internal connector/cable for direct motherboard connection
• Typical use: maintains time and BIOS settings during power-off periods

How to use

Before replacing the internal RTC battery, power down the device and disconnect it from mains and any external power sources. Open the device casing following the manufacturer’s service instructions to access the motherboard. Disconnect the old coin-cell module carefully from its connector and replace it with the new RTC battery, ensuring the connector is fully seated and the polarity is correct. Reassemble the device and power it on; check BIOS settings and system time and reconfigure if necessary.

Recommendations

Use this replacement battery only in compatible Lenovo devices and follow anti-static precautions during installation. Do not expose the battery to high temperatures or open flames. If unsure about disassembly or compatibility, consult an authorized service center or the device’s maintenance manual.