# Standby Battery Calculation Charts: Fire Applications

```Standby Battery Calculation Charts: Fire Applications
The PC5020 control panel provides regulated current for the panel, auxiliary, PGM outputs and Keybus connected modules. The bell circuit on the main panel is not used for fire alarm notification appliances which means that alarm current
is not a part of the main panel battery calculation.
All components that draw power from the main panel must be considered in the standby battery calculation. This
includes any 2-wire smoke detectors connected to the PGM2. Consult the smoke detector manufacturer’s installation
documents for current draw.
To calculate the minimum size of standby battery required for your system:
1. Calculate the Keybus load using chart 2. Transfer the total to chart 1.
2. Complete the rest of chart 1.
3. Total the current draw in chart 1 and write the total in box 1 of the calculation below the chart.
NOTE: Total current draw must not exceed 480mA.
4. Complete the calculation steps below chart 1. The answer in box 5 is the minimum standby battery size.
5. If the standby battery size calculated exceeds 14Ah (2 - 7Ah batteries fit in the cabinet) then either
• install the PS5350 external battery charger, which can take batteries up to 60Ah in size.
NOTE: When entering values in the charts below, please use the maximum specified ratings of the devices (ex. each 2wire smoke detector -maximum current rating).
Chart # 1 - Panel overall calculation
Outputs or components drawing current from the panel
Current
(mA)
Notes
PC5020 panel {65mA}
65mA
fixed
PC5700 {150mA} or T-Link {150mA} (required)
150mA
fixed
PGM 1 output {50mA max.}
see Note 2, 3
PGM 2 output {300mA max.}
see Note 2, 3
PGM 3 output {50mA max.} (PC5020(CF) only)
see Note 2, 3
PGM 4 output {50mA max.} (PC5020(CF) only)
see Note 2, 3
Aux output on the main panel {420mA max.}
see Note 2
from Chart 2
NOTE 1: For 60 hour
standby time, at a
maximum current of
480mA the battery size
must be 35Ah or greater.
For 24 hour standby
time, at a maximum
current of 480mA, the
battery size must be 14Ah
or greater. Under no
circumstances can the
maximum current in line 1
exceed 480mA.
Alarm Current {700mA}
Total current from the main control panel {See Note 1} ...................................... 1
mA
X
Standby time {24 or 60 hours} ................................................................................... 2
Total Alarm Current.................................................................................................... 3
Hours
A
Signaling Alarm Time (5 minutes or 0.0833 hours) ........ 700mA x 0.0833 hours =
58.3*
Multiply total standby current in mA (1) and alarm current (3)
by the standby time in hours (2). Write total in box 4........................... (1 x 2) = 4
A+58.3
Derating factor & conversion to Amp-Hours ........................................................ 5
0.0012
Multiply (4) by the derating factor (5)...................................................... (4 x 5) = 6
* This value of 58.3mAh is
to be implemented in the
battery calculation only if
Bell Output is used. For
Burglary Application only.
X
Amp-Hour
This is the minimum size battery required to maintain the main panel for the standby time selected
NOTE 2: Aux+ is shared between Aux+, Keybus,
(Red, Blk, Yel, Grn) & all PGM outputs. Minimum
PC5700 (150mA), available current for Aux+,
Keybus and PGM outputs should total 180mA.
PC5O2O(CF) v3.X
Item
Current
Quantity
(mA)
x
LCD5500(Z) series
85
x
LCD5501Z
85
x
PC5100 + AML devices*
40
x
PC5108
35
x
PC5200
20
x
PC5400
65
x
PC5204
20
x
Total
(mA)
1
85mA
Total for chart 2 (current on the Keybus)...................................................................
Transfer to Chart 1.
*Refer to Addressable Loop Current Calculation Chart (from PC5100 Installation Instructions) for total
NOTE 3: PGM1, PGM2, PGM3 and PGM4 can be used as standard PGM outputs. Each PGM output can sink up to 50mA maximum (PGM2 can sink up
to 300mA).