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Remove the CMOS battery

Use this information to remove the CMOS battery.

About this task

  • Lenovo has designed this product with your safety in mind. The lithium battery must be handled correctly to avoid possible danger. If you replace the CMOS battery, you must adhere to local ordinances or regulations for battery disposal.
  • If you replace the original lithium battery with a heavy-metal battery or a battery with heavy-metal components, be aware of the following environmental consideration. Batteries and accumulators that contain heavy metals must not be disposed of with normal domestic waste. They will be taken back free of charge by the manufacturer, distributor, or representative, to be recycled or disposed of in a proper manner.
  • Power off the server and disconnect all power cords for this task.

    disconnect all power
    The power-control button on the device and the power switch on the power supply do not turn off the electrical current supplied to the device. The device also might have more than one power cord. To remove all electrical current from the device, ensure that all power cords are disconnected from the power source.
  • Prevent exposure to static electricity, which might lead to system halt and loss of data, by keeping static-sensitive components in their static-protective packages until installation, and handling these devices with an electrostatic-discharge wrist strap or other grounding system.


  1. Remove the top cover. See Remove the top cover.
  2. Remove any parts and disconnect any cables that might impede your access to the CMOS battery.
  3. Locate the CMOS battery. See System board.
  4. Press the battery clip as shown and carefully lift CMOS battery out of the socket.
    • Failing to remove the CMOS battery properly might damage the socket on the system board. Any damage to the socket might require replacing the system board.

    • Do not tilt or push the CMOS battery by using excessive force.

    Figure 1. CMOS battery removal
    CMOS battery removal

After you finish

After you replace the CMOS battery, you must reconfigure the server and reset the system date and time.
  1. Install a new one. See Install the CMOS battery.

  2. Dispose of the CMOS battery as required by local ordinances or regulations.


    When replacing the lithium battery, use only Lenovo specified part number or an equivalent type battery recommended by the manufacturer. If your system has a module containing a lithium battery, replace it only with the same module type made by the same manufacturer. The battery contains lithium and can explode if not properly used, handled, or disposed of.

    Do not:
    • Throw or immerse into water
    • Heat to more than 100°C (212°F)
    • Repair or disassemble

    Dispose of the battery as required by local ordinances or regulations.

Demo video

Watch the procedure on YouTube