PRAESENSA
System composition | en
41
Bosch Security Systems B.V.
Installation manual
2019.11 | V1.00 |
5.4.4
Accurate battery size calculation
The size or capacity of the battery for each cluster of devices, consisting of a PRA-MPS3, up to
three amplifiers and optionally a system controller and a call station, can be calculated by
using the current taken from the battery for each device element, as shown in the previous
section.
Of importance is for how long the system must be able to operate on the battery. Most
emergency sound systems are specified to run on battery for 24 hours in quiescent mode and
then subsequently for 30 minutes doing (voice) alarms.
System example
Consider a voice alarm system that consists of the devices as shown in the next table.
Device
Device elements
Current
taken
from
battery
[A]
Time in
quiescent
mode [h]
Time in
alarm
mode
[h]
Current
x time
[Ah]
PRA-SCL
System controller
+ per active RJ45 port (2)
0.35
2 x 0.04
24
24
0.5
0.5
8.58
1.96
PRA-CSLD
Call station
+ per active RJ45 port (2)
+ per extension PRA-CSE (3)
+ with alarm option
0.42
2 x 0.05
3 x 0.01
0.12
24
24
24
24
0.5
0.5
0.5
0.5
10.29
2.45
0.73
2.94
PRA-AD604
Amplifier (sleep)
Amplifier (snooze)
Amplifier (active, idle)
Amplifier (active, low power)
Amplifier (active, full power)
+ per active RJ45 port (2)
0.50
0.71
3.25
5.33
20.83
2 x 0.03
-
24
-
-
-
24
-
-
-
-
0.5
0.5
-
17.04
-
-
10.41
1.47
PRA-AD608
Amplifier (sleep)
Amplifier (snooze)
Amplifier (active, idle)
Amplifier (active, low power)
Amplifier (active, full power)
+ per active RJ45 port (2)
0.50
0.77
4.00
7.33
22.83
2 x 0.03
-
24
-
-
-
24
-
-
-
-
0.5
0.5
-
18.48
-
-
11.41
1.47
PRA-AD608
Amplifier (sleep)
Amplifier (snooze)
Amplifier (active, idle)
Amplifier (active, low power)
Amplifier (active, full power)
+ per active RJ45 port (2)
0.50
0.77
4.00
7.33
22.83
2 x 0.03
-
24
-
-
-
24
-
-
-
-
0.5
0.5
-
18.48
-
-
11.41
1.47
PRA-MPS3
Multifunction power supply
+ per active RJ45 port (2)
+ per active SFP port
0.43
2 x 0.03
0.06
24
24
-
0.5
0.5
-
10.53
1.47
-
Total calculated battery capacity [Ah]
Required battery capacity (30% oversized) [Ah]
130.59
170
Summary of Contents for PRAESENSA
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