Panasonic Toughbook CF-18BCAGCMM Reference Manual page 43

Battery Power
43
NOTE
After switching from [Normal Temperature] to [High Temperature] or vice versa, the
remaining battery capacity will not be displayed properly until the battery pack is
completely discharged or fully charged.
In the [Auto] mode:
Once the computer has automatically switched from the normal temperature mode to
the high temperature mode, the computer will not switch back to the normal tempera-
ture mode until the battery has been used and recharged to a total charge level of
about five times as much as that of the fully-charged state. This is to prevent the
deterioration of the battery.