Power
Hardware and Software Guide 3–19
Calibrating a Battery Pack

When to Calibrate

Even if a battery pack is heavily used, calibration should be
necessary only once a month. You do not have to calibrate a new
battery pack before first use.
Calibration does not usually increase battery run time, but it can
increase the accuracy of battery charge displays, especially under
the following conditions:
■When the battery pack has been unused for one month
or more.
■When the notebook has been running primarily on
external power (and rarely on battery power) for more
than one month.
■When battery charge displays report large changes in the
percent of power remaining within 2 minutes. For example,
if the Power Meter displays 20 percent of a full charge
remaining and then less than 2 minutes later displays only
5 percent of a full charge remaining, the rapid drop in charge
remaining indicates that the battery pack needs calibration.
For more information about battery charge displays, refer to
the “Monitoring the Charge in a Battery Pack” section earlier
in this chapter.