Checking Operational Charging: To check
operational charging, use a discharged battery pack or a
battery pack that has less than 50% of the total power
remaining when installed in the computer.
Perform operational charging. If the battery status
indicator does not turn on, remove the battery pack and
leave it to return to room temperature. Reinstall the
battery pack. If the charge indicator still does not turn on,
replace the battery pack.
Checking the Battery Pack: Battery charging will
not start until the Fuel-Gauge shows that less than 95% of
the total power remains; with this condition the battery
pack will charge to 100% of its capacity. This protects the
battery pack from being overcharged or having a
shortened life.
Do the following:
1. Power off the computer.
2. Remove the battery pack and measure the voltage
between battery terminals 2 (+) and 6 (−). See the
following figure:
2
6(-)
(+) (T)

5

Note
Signal lines, not used in these steps, are used for
communication between the system and the
battery.
Terminal Voltage (V dc) / Signal
1 —
2+8 to +13.5
3 —
4 —
5 Thermal
6 Ground (−)
102 IBM Mobile Systems - ThinkPad HMM Volume 3