Sony PCG-XG29 - Manual (Page 66)

VAIO® Notebook User Guide #"
Using a Second Battery Pack
You can purchase a second rechargeable battery pack. With two battery
packs, you can extend the time that you use your computer with battery
power. When using two battery packs, the battery pack you insert first
charges first. The battery pack you insert second charges when the first
battery pack is 85% full. You can monitor which battery pack is charging
by observing the battery indicator lights.
To insert a second battery pack
1
If another device is in the multipurpose drive bay, remove the device.
See “To remove the DVD-ROM drive (Windows 98® models)” on
page 37.
2
Insert the battery pack into the multipurpose drive 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.
Insert the tab of the weight saver into the hollow of the multipurpose
drive bay slot, and then push the weight saver into the multipurpose
drive bay until it clicks.
Battery pack
Multipurpose drive bay
Label side facing down