Section 6: battery calculations – Fire-Lite 411UDAC Fire Alarm Communicator User Manual
Page 64
64
411UDAC Manual — P/N 51073:E 9/20/2013
Section 6: Battery Calculations
Use the Total Standby and Alarm Load Currents calculated in Tables 6.2, and 6.3, for the following
battery calculations.
1. Select a battery with an Amp Hour rating greater than that calculated in Table 6.1.
NFPA 72 for Central Station and Proprietary Protected Premises systems require 24 hours of
standby
2. Two 12 VDC, 7 Amp Hour batteries, wired in parallel, can be located in the backbox to
provide 14 Amp Hours of backup (refer to Figure 2.4 on page 22 for battery cable connections)
Standby Load
Current in amps
[ ]
X
Required Standby Time in Hours
(24 or 60 Hours)
[ ]
=
__________
Alarm Load
Current in amps
[ ]
X
Required Alarm Time in Hours
(i.e. 5 min. = 0.084 Hours)
[ ]
=
__________
Add Standby and Alarm Load for Required Ampere Hour Battery
__________
Multiplying by derating factor of 1.2
X1.2
Total Ampere Hour Battery
1
=
__________
Table 6.1 Battery Calculations