# Battery Size Calculations - Siemens PAD-3 Installation, Operation And Maintenance Manual

Distributed power module nac expander

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## 6.2 BATTERY SIZE CALCULATIONS

Device
Quantity
Multiply
This column times this column
1) PAD-3 Control
1 or 2
Unit
2) PAD-3 Control
1 or 2
Unit
Notification Appliances – refer to the device manual for ratings
Model No.
Quantity
3)
Auxiliary Devices – refer to the device manual for ratings
Model No.
Quantity
4)
5) Total amperage required (totals for line 1, 2, 3 and 4)
6) Number of Standby Hours required (4, 24, or 60, per NFPA 72)
7) A.H. for Standby (without AC reporting delay) Multiply line 5 times line 6
8) A.H. for AC reporting delay
9) Total A.H for Standby (add line 7 and line 8)
10) Length of Alarm Operation
11) A.H for Alarm (multiply line 5 times line 10)
12) Total Standby and Alarm A.H required (add line 9 and line 11)
13) Battery De-rating Factor
14) Battery Amp-Hour Rating required (multiply line 12 times line 13)
A.
Up to two PAD-3 boards can be connected to a common battery set. When calculating for 2 PAD-3 boards
I.
Both boards must be mounted on System 3 rails in the same enclosure.
II.
One of the boards must have the battery charger circuit disconnected.
III.
The board with the ACTIVE charger is limited to 1.50 amps for the aux. power (terminals 18 and 19).
IV.
Both sets of battery connections are to be connected to the same battery set using 2 battery connection splitters, P/N 230-
299203.
B.
The Alarm Current must never exceed 6.14 amps! (6 amps output for NACs and aux. power, 0.14 amps for internal operation)
C.
A.H. required for AC reporting delay – 0 hours = 0.00 A.H.; 60 minutes = 0.24 A.H.; 120 minutes = 0.60 A.H.; 180 minutes =
0.96 A.H.
D.
Alarm operation length while on battery power varies with application and local codes. Check with the AHJ to determine if 5
minutes (0.0833 hours), 30 minutes (0.5 hours), 1 hour, or 2 hours of alarm operation is required.
E.
Battery rating required cannot exceed 15 A.H. For battery ratings 7.0 A.H. or below, the full 3.0 amps are available for auxiliary
power (terminals 18 and 19). For battery ratings between 7.0 and 15 A.H., 1.50 amps are available for auxiliary power.
F.
The following table shows the maximum standby current allowed: When the Auxiliary Power Output is programmed to
shutdown on AC power fault (SW1.4-ON), up to 3.015 Amps is allowed.
Current per device
(amps)
A
Aux. Pwr. always on (SW1-4 off) – 0.035A
Aux. Pwr. off @ AC fail (SW1-4 on) – 0.015A
A
0.140 per PAD-3
Alarm current
Standby current
C
D
Standby
Maximum Standby Current (A.)
Hours
7AH
4
1.242
24
0.207
60
0.082
90
0.055
Alarm current
B,F
E
10AH
15AH
1.842
2.842
0.307
0.473
0.122
0.189
0.081
0.126
40
Standby
Alarm
current
current
(A)
(A)
=current
A
A
Hrs.
A.H.
A.H.
Hrs.
A.H.
A.H
1.25
A.H.

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