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102
Mobile Computing
Charging batteries
The battery may not start charging immediately under the following
conditions:
❖
The battery is extremely hot or cold.
To ensure that the battery charges to its full capacity, wait until
it reaches room temperature (50 to 80 degrees Fahrenheit, 10 to
26 degrees Celsius).
❖
The battery is almost completely discharged.
Leave the power connected and the battery should begin
charging after a few minutes.
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
NOTE
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.
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.
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.
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