FireSwitch108 - 13 -
Battery Calculation Worksheet
Device
Number of
Devices
Current per Device
Stand-by
Current
Alarm
Current
For each device use this formula: This column x This column = Equals Current per number of devices.
FireSwitch108
(Current draw from battery)
1
Stand-by: 180mA 180mA
Alarm: 200mA 200mA
A FireSwitch Current
180mA 200mA
Auxiliary Devices Refer to device manual for current ratings.
Alarm/Stand-by mA mA mA
Alarm/Stand-by mA mA mA
Alarm/Stand-by mA mA mA
B
Auxiliary Devices Current
(must not exceed 1A; 0.45A for Canadian applications)
Refer to device manual for current ratings.
Alarm: mA 0mA mA
Alarm: mA 0mA mA
Alarm: mA 0mA mA
Alarm: mA
0mA mA
C
Notification Appliances Current must not exceed 10A (10,000mA) 0mA
mA
D
Total alarm current (A + B + C) mA mA
E
Total current ratings converted to amperes (line D x .001) A A
F
Number of standby hours (24 for NFPA 72, Chapter 1, 1-5.2.5). H
G
Multiply lines E and F. Total stand-by AH AH
H
Alarm sounding period in hours.
(For example, 5 minutes = 0.0833 hours.)
H
I
Multiply lines E and H. Total alarm AH AH
J
Add lines G and I. Total stand-by and alarm AH AH
K
Multiply line J by 1.30.
(30% extra insurance to meet desired performance)
Total ampere - hours required
AH
If total ampere - hour required exceeds 40AH, decrease AUX current to provide enough stand-by time for the
application. Select a battery with AH rating equal to or greater than the value calculated.
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