HP EliteBook 840 G3 - Manual (Page 49)

Connect the computer to external AC power under any of the following conditions:
● When charging or calibrating a battery
● When installing or modifying system software
● When writing information to a CD, a DVD, or a BD (select products only)
● When running Disk Defragmenter
● When performing a backup or recovery
When you connect the computer to external AC power, the following events occur:
● The battery begins to charge.
● If the computer is turned on, the power meter icon in taskbar changes appearance.
When you disconnect external AC power, the following events occur:
● The computer switches to battery power.
● The display brightness is automatically decreased to save battery life.
Setting power options 39