IBM X24, X23, X22, X20, X21 manual Checking the backup battery Do the following

If the charge indicator or icon still does not turn on, replace the battery pack. If the charge indicator still does not turn on, replace the system board. Then reinstall the battery pack. If the reinstalled battery pack has not been charged, go to the next section.

Checking the battery pack: Battery charging does not start until the Fuel Gauge shows that less than 95% of the total power remains; under this condition the battery pack can charge to 100% of its capacity. This protects the battery pack from being overcharged or from having a shortened life.

Note: If the battery pack becomes hot, it may not be able to charge. Remove it from the computer and leave it at room temperature for a while. After it cools down, reinstall and recharge it.

To check the battery pack, do the following:

1.Power off the computer.

2.Remove the battery pack and measure the voltage between battery terminals 1 (+) and 4 (-). See the following figure:

	1(+)
	2
	3
	4(-)
Terminal	Voltage (V dc)
1	+ 0 to + 12.6 (6-cell) +0 to 16.8(4-cell)
4	Ground (-)

3.If the voltage is less than +11.0 V dc, the battery pack has been discharged.

4.If the voltage is more than +11.0 V dc, measure the resistance between battery terminals 3 and 4. The resistance between battery terminals 3 and 4 must be from 4 to 30k ohms.

Note: Recharging will take at least 3 hours, even if the indicator does not turn on.

If the voltage is still less than +11.0 V dc after recharging, replace the battery.

Checking the backup battery: Do the following:

1.Power off the computer, and unplug the AC adapter from it.

Chapter 2. General descriptions 37