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Option 11C and 11C Mini Technical Reference Guide
NTAK75 extended battery back-up unit
The batteries supplied with the NTAK75 have an average useful life of four
years, meaning the batteries are depleted to 80% of capacity, and backup time
is diminished. After this period of time the batteries should be replaced. For
more information refer to Option 11C and 11C Mini Fault Clearing (553-
3011-500). The mean time between failures (MTBF) of the NTAK75 without
batteries is 100 years at 25° C.
Table 60
Dimensions of NTAK75 and NTAK76 batteries
Card Length Width Depth
NTAK75 19” (480 mm) 11.5” (290 mm) 11” (280 mm)
NTAK76 12.25” (312 mm) 9.75” (250 mm) 6.25” (160 mm)