Sony PCG-F640 VAIO User Guide (primary manual) User Manual page 26

VAIO Notebook User Guide
Using Battery Power
You can use one or two battery packs as a source of power. The second battery
pack inserts into the multipurpose bay on the right side of the computer. (See
"Power Saving Modes" on page 77.) Additional battery packs are available as a
separate option.
The battery pack that comes with your computer is not fully charged at the time
of purchase. Follow the steps below to insert and charge the battery pack.
To insert the battery pack
1 To open the battery bay, press cover down.
Cover swings out but does not detach.
Battery bay
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