70 Mobile Computing

Charging batteries

TECHNICAL NOTE: The recharging of the battery may
not occur when your device is using all of the power
provided by the AC adaptor to run applications, features,
and devices. Your device's Power Options utility can be
used to select a power level setting that reduces the
power required for system operation and will allow the
battery to recharge.
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.
HINT: Once the battery is fully charged, we recommend
that you periodically operate your device on battery
power until the battery discharges completely.
Please make a complete back up of your data to external
media before discharging the battery. For more
information, see “Backing up your work” on page 65
Charging the RTC battery
Your device has an internal real-time clock (RTC) battery. The
RTC battery powers the System Time Clock and BIOS
memory used to store your device’s configuration settings.
When fully charged, it maintains this information for up to a
month when the device is powered off.
The RTC battery may have become completely discharged
while your device was shipped, resulting in a CMOS error
message during startup. The error message may vary by
device model.