26
en | Installation wiring
PRAESENSA
2021.12.21 | V0.15b | F.01U.402.882
Underwriters Laboratories Listing Document (ULLD)
Bosch Security Systems B.V.
3.2.3
Power consumption
The following table gives an overview of the power demand of the PRAESENSA devices for the
different operating conditions.
Device
Device elements
Power
consumption
[W]
Power from
battery [W]
Current
from
battery [A]
PRA-SCL
System controller
+ per active RJ45 port
3.9
0.4
4.2
0.5
0.35
0.04
PRA-CSLD /
PRA-CSLW
Call station
+ per active RJ45 port
+ per extension PRA-CSE
+ with alarm option
4.2
0.5
0.1
1.2
5.0
0.6
0.1
1.5
0.42
0.05
0.01
0.12
PRA-AD604
Amplifier (sleep)
Amplifier (snooze)
Amplifier (active, idle)
Amplifier (active, low power)
Amplifier (active, full power)
+ per active RJ45 port
6.0
7.5
36
50
222
0.4
6.0
8.0
43
60
244
0.4
0.50
0.67
3.58
5.00
20.33
0.03
PRA-AD608
Amplifier (sleep)
Amplifier (snooze)
Amplifier (active, idle)
Amplifier (active, low power)
Amplifier (active, full power)
+ per active RJ45 port
6.0
8.9
56
77
246
0.4
6.0
9.5
68
93
271
0.4
0.50
0.79
5.67
7.75
22.58
0.03
PRA-ES8P2S
Ethernet switch
+ per active RJ45 port
+ per active SFP port
+ PoE load
7.0
0.4
0.7
load
8.4
0.5
0.8
1.2 x load
0.70
0.04
0.07
0.1 x load
PRA-MPS3
Multifunction power supply
+ per active RJ45 port
+ per active SFP port
5.2
0.4
0.7
5.2
0.4
0.7
0.43
0.03
0.06
PRA‑FRP3‑US
First responder panel incl. 2
active RJ45 ports, 36 buttons
and alarm option.
6.7
8.0
0.67
3.2.4
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.