Agilent Technologies U1253B User's And Service Manual page 154

5 Maintenance
C A U T I O N
130
8 Once the charging is completed, the FULLY CHARGED
message will be displayed. A trickle charging current will
be drawn to maintain the battery capacity.
9 Remove the DC adapter when the battery has been fully
charged.
Do not turn the rotary switch before removing the adapter from the
terminals.
U1253B User's and Service Guide