Appendix B: Battery Calculations (Selection Guide)
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Appendix B: Battery Calculations (Selection Guide)
Use the form below to determine the required batteries.
Total Current Requirement
ALARM (
B
)______ Amps.
Battery Capacity Requirement
(
[STANDBY (
A
) ______ ] X [(24 or 60 Hours) ________ ]
)
+
(
[ALARM (
B
) ______ ] X [
♣
Alarm in Hr.] ________
)
= (
C
) ________AH
Battery Selection
Multiply (
C
) by 1.20 to derate battery.
* Assuming three initiating circuits in alarm.
♣
Use
0.084
for five minutes of alarm or
0.5
for thirty minutes of alarm as a multiplier figure.
♦
Using the
MIR-525/U
2-wire smoke detector. See Appendix "A", for other available smoke detectors .
IMPORTANT NOTICE
The main AC branch circuit connection for the Fire Alarm Control Unit must provide a dedicated
continuous power without provision of any disconnect devices. Use #12 AWG wire with 600-volt
insulation and proper over-current circuit protection that complies with the local codes.
Power Requirements (All currents are in amperes)
Model
Number
Description
Qty
Standby
Total
Standby
Alarm
Total
Alarm
PFC-3005T
Fire Alarm, 5 Det,
2 Sig
X
0.114
=
0.200
=
RA-105
Annunciator, 5
Cir
X
0.016
=
0.032
=
RTI-1
Remote Trouble
Indicator
X
0.035
=
0.035
2-Wire Smoke Detectors
X
♦
0.0001
=
* 0.090
= 0.090
4-Wire Smoke Detectors
X
=
=
Signal Load (bells, horns,
strobes, and etc.)
=
Total currents (Add above currents)
Standby
(
A
)
(
B
)
Note:
Batteries BT-40 (4.0AH) and BT-80 (8AH) fit into the backboxes; all larger batteries
such as BT-120 (12AH) and the BT-180 (18AH) require an external battery box.