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 .
