Sony PCG-F640 - Manual (Page 53)

Using a Second Battery Pack
53
To insert a second battery pack
1 If another device is in the multipurpose bay, remove the device.
2 Insert the battery pack into the multipurpose bay.
If the battery is being used, the battery 2 indicator light turns on.
3 Attach the weight saver to the computer to stabilize the battery pack. There
is a RELEASE lever on the bottom of the weight saver. Slide the lever
toward the front of the computer to lock the weight saver. See also “Using
the Weight Saver” on page 56.
Second battery in multipurpose bay
Using weight saver for second battery cover
Battery pack
Multipurpose bay
Label side facing down
Battery pack
Weight saver