Checking The Backup Battery - Lenovo ThinkPad X240s Maintenance Manual

To check whether the battery packs charge properly during operation, do the following:
1. Discharge the battery packs until the remaining battery power is less than 50%.
2. Connect the computer to ac power to charge the battery packs. If the battery status icon in the
Windows notification area indicates that the batteries are not charging, remove the battery packs and
let them return to room temperature.
3. Reinstall the battery packs. If the batteries are still not charging, replace the battery packs.
4. Check the battery status icon again. If the same error still exists, replace the system board.

Checking the backup battery

To check the backup battery, do the following:
1. Disable the built-in battery. See "Disabling the built-in batteries" on page 58.
2. Remove the backup battery. See "1020 Front battery" on page 60.
3. Measure the voltage of the backup battery.
• If the voltage is correct, replace the system board.
• If the voltage is not correct, replace the backup battery.
• If the backup battery discharges quickly after replacement, replace the system board.
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Hardware Maintenance Manual
Wire
Voltage (V dc)
Red +2.5 to +3.2
Black Ground