FPD-7024 | Operation and Installation Guide | 1.0 Overview
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Bosch Security Systems, Inc. | 1/10 | F01U008458-03
The units shown in Table 5 are Amp hours (Ah), and the figures include a 20% derating factor.
Table 5: Required Battery Size Calculation
Grand Total Standby Existing (in amps) CS
Total Hours of Standby Required (usually 24 or 60): HS
Total Standby Capacity (multiply CS X HS) TS= CS X HS
Grand Total Alarm Existing (in amps) CA
Total Hours of Alarm Time Required (usually 0.083 or 0.25): HA
Total Standby Capacity (multiply CA X HA) TA= CA X HA
Total Capacity Required (add TA + TS): TC = TA + TS
Required Capacity with 20% Derating (TC X 1.2) C = TC X 1.2
The required battery size to support the system can be calculated using Table 6 and Table 7
on page 13.
1.2.11 Standby Existing Load
Use Table 6 to estimate the size of the battery required to support the standby load, then use Table 7 on page
13 to estimate the size of the battery required to support the alarm load. Add the results together for the total
battery size. Select the next larger standard battery for the system. If the results show a requirement for a
battery over 40 Ah, reduce the existing or add an external regulated fire protective signaling power supply.
Table 6: Standby Load Battery Size (Ah)
Standby Load Battery Size Chart Capacity Required for
24 Hours
Capacity Required for
48 Hours
Capacity Required for
60 Hours
Grand Total Standby Existing
100 to 200 mA 5.8 11.5 14.4
201 to 300 mA 8.6 17.3 21.6
301 to 400 mA 11.5 23.0 28.8
401 to 500 mA 14.4 28.8 36.0
501 to 600 mA 17.3 34.6 X
601 to 700 mA 20.2 X X
701 to 800 mA 23.0 X X
801 to 900 mA 25.9 X X
901 to 1000 mA 28.8 X X
1001 to 1100 mA 31.7 X X