NEC VERSA LXi Service And Reference Manual page 29

Insert the new battery as follows:
5.
Locate the alignment groove on the edge of the battery.
!
Locate the alignment groove inside the battery bay.
!
Align the grooves on the battery with the grooves in the bay.
!
! Slide the battery into the bay until securely locked into place.
Turn over the system.
6.
2-8 System Configuration and Setup
Inserting the battery