TAG MIL-BOOK 20 Series - Manual (Page 71)

3-6 Managing Power
pack from your dealer and keep it with you in a fully charged state as a
backup.
To replace the battery pack, follow these steps:
1. Make sure the computer is not turned on or connected to AC power.
However, the Tablet PC supports the battery hot-swap function,
providing you the ability to replace the battery even during system
on.
2. Carefully place the computer upside down.
3. Open the stand fully ( ).
4. Slide the release lever ( ) to the right and pull the battery pack out of
its compartment ( ) by using your thumb and index finger.
5. Insert the new battery pack into the compartment and slide the release
lever first to the right to accommodate it, then releasing it to the lock
position.