Faraday FireWatch 400 - Battery Size Calculations

Appendix A. Reference Data
A-2 P/N 446613 Issue I Rev. A
Battery Size Calculations
Standby
Current (A.)
Alarm
Current (A.)
Control Unit (4 zones) .075 .300
City Tie Board Standby .015 .015 + NA
Alarm .035 .035 NA +
w/ Alarm Tie - add Standby .010 .010 NA
Alarm .010 .010 NA +
w/ Trouble Tie - add Alarm .010 .010 NA
Alarm .010 .010 NA +
Alarm Relay Board Standby .010 .010 + NA
Alarm .035 .035 NA +
Remote LED Standby .010 .010 + NA
Annunciator Driver Alarm .015 .015 NA +
7704 / 7704-01 Standby .040 .040 + NA
LED Annunciator Alarm .060 .060 NA +
7700 / 7700-01 Standby .040 .040 + NA
Trouble Unit Alarm .040 .040 NA +
2-wire Smoke Detectors:
Catalog # Quantity X Current (A)
X = + NA
X. = + NA
X = + NA
The detector models may be mixed and matched as long as the total maximum standby current does not
exceed 3.0 mA per initiating device circuit. The total number of detectors on a circuit should not exceed 30.
4-wire Smoke Detectors
Catalog # Quantity X Current (A.)
Standby X = + NA
Alarm X = NA +
Standby X = + NA
Alarm X = NA +
Standby X = + NA
Alarm X = NA +
End of Line Relay
Catalog # Quantity X Current (A.)
X = + +
Notification Appliances
Catalog # Quantity X Current (A.)
X = NA +
X = NA +
X = NA +
X = NA +
Other = + +
TOTAL
Total Standby Current
(from above)
Hours of Standby Required per
NFPA 72 Standard (4, 24 or 60)
AH for Standby
A. x ____ Hours =
Total Alarm Current
(from above)
5 Minutes of Alarm Operation
per NFPA 72 Standard*
AH for Alarm
A. x 0.33 Hours =
A.H. for
Standby
A.H. for
Alarm
A.H. Required
Battery Capacity
+=
Notes: * An additional multiplier is included to compensate for the higher discharge rate in alarm.
** Battery capacity decreases with age. A 4-year old battery can lose up to 50% of its capacity.
Compensations should be made to allow for this loss.
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