Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 60)

Chapter
Installing and Replacing Components 3
3 -8
The battery backs up 24K bytes of user RAM and the clock/calendar.
Drain on the battery should be less than 0.5 mA dc during battery back-up
(no power) and less than 50 uA while the module is powered. Battery life
during no-power conditions is about 2,000 hours. Battery shelf life is
about 20,000 hours.
When the BTLO LED indicator light comes on the battery should maintain
the clock and program data for about three days. We recommend
immediate replacement.
The BASIC module ships with a MAXELL ER3STC battery. You can
replace it with this battery or a Allen-Bradley battery, catalog number
1770-XZ or a Tadiran battery, part number 15-51-03-210-000.
Important: The BASIC module retains the current configuration for 36
minutes after removing the battery. If it takes you longer than 36 minutes
to replace the battery, you lose the program stored in RAM.
ATTENTION: Do not incinerate or dispose lithium batteries in
general trash collection. They may explode or rupture violently.
Check state and local regulations dealing with the disposal of
these materials. You are legally responsible for hazards created
while your battery is being disposed.
Ship or dispose the battery according to the recommended
procedures listed in the disposal section of Guidelines for
Handling Lithium Batteries (publication number AG-5.4).
Use CALL 80 (page 13 -9) to monitor battery status.
Install the Battery