IBM 310ED - Manual (Page 34)

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:
1. If the battery status indicator does not turn on,
remove the battery pack and allow it to return to room
temperature.
2. Reinstall the battery pack. If the charge indicator still
does not turn on, replace the battery pack.
Checking 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 6 (-). See the
following figure:
Note: Signal lines, not used in these steps, are used
for communication between the system and the
battery.
3. If the voltage is less than +11.0 V dc, the battery pack
has been discharged. Recharge the battery pack.
If the voltage is still less than +11.0 V dc after
recharging, replace the battery.
Note: If the voltage of the battery pack is 0 V dc, it
is not defective.
Terminal Voltage (V dc) / Signal
1 0 to 13
2 ID
3 Thermal
4 Data
5 Reserved
6 Ground
10 IBM Mobile Systems ThinkPad 310 (D/E/ED) HMM