How long does the battery module of the S7-200 CPUs last?
The optional battery module of the S7-200 is not used before the high performance capacitor of the CPU is discharged. The battery module is not used for short-term power failures that can be covered by the time for saving data provided by the high performance capacitor. The usually expected utilization duration is 200 days after the high performance capacitor has been discharged. The maximum life cycle for a battery module is 10 years without utilization. The data buffering time of the high performance capacitor depends on the CPU. Further information on the CPU-determined buffering times can be found under Entry-ID 431638. To achieve the full capacity of the high performance capacitor, the CPU must be supplied continously with tension during 24 hours.
