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Mobile Computing
Charging batteries
HINT: Once the battery is fully charged, we recommend that you
operate your computer on battery power until the battery discharges
completely. Doing this extends battery life and helps ensure accurate
monitoring of battery capacity.
Charging the RTC battery
Your computer has an internal real-time clock (RTC) battery. The
RTC battery powers the System Time Clock and BIOS memory
used to store your computer’s configuration settings. When fully
charged, it maintains this information for up to a month when the
computer is powered off.
The RTC battery may have become completely discharged while
your computer was shipped, resulting in the following error
message during startup:
BAD RTC BATTERY
BAD CHECKSUM (CMOS)
CHECK SYSTEM
The above error message may vary by computer model.
The RTC battery does not charge while the computer is turned off
even when the AC adaptor is charging the computer. The RTC battery
charges when the computer is powered on.
If the RTC battery is low, the real-time clock and calendar may
display the incorrect time and date, or stop working.
To recharge the RTC battery, plug the computer into a live electrical
outlet and leave the computer powered on for 24 hours.
It is seldom necessary to charge the RTC battery because it charges
while the computer is on. If the RTC battery is low, the real-time
clock and calendar may display the incorrect time and date or stop
working.
When Hibernation mode is enabled and the RTC battery is
completely discharged, a warning prompts you to reset the real-time
clock.
The computer can be used while the RTC battery is being charged,
although the charging status of the RTC battery cannot be
monitored.
NOTE
NOTE