Appendix
116
Siemens Building Technologies
Fire Safety & Security Products
09.2008
16.6 Appendix G: Calculating the Battery Power Requirements
It is important that adequate stand-by power is available to supply all devices in the
event of a Mains supply failure. To ensure that enough power is available, always
connect the appropriate back-up battery and PSU.
The table below gives an approximation of the maximum load current that can be
drawn from each type of battery over the given stand-by periods of 12 hours, 30
hours and 60 hours.
The approximations below assume that the SPC Controller PCB is drawing its
maximum load (no auxiliary load connected, no external bells connected, no
diallers plugged) and that the usable output power from the battery is 85% of its
maximum capacity.
0.85 x Max Battery Capacity (AH)
Standby Time (Hours)
-
SPC Controller Current
= Max available load current
Device with PSU
SPC5000
SPC6000
SPC4000
SPCP332/333
Max. controller current
Approx. 200 mA
Approx. 100 mA
Battery
7 AH
17 AH
7 AH
17 AH
12 hours
296 mA
1004 mA
396 mA
1104 mA
30 hours
n.a
282 mA
98 mA
382 mA
Standby
Time
60
hours
n.a. n.a. n.a. 141
mA
Tab. 30
Battery Standby Time
See Appendix F for maximum load of devices and modules.
Values listed as N / A indicate that the selected battery does not have the capacity
to power the minimum load of just the SPC Controller for the given standby time.
NOTE
Only Sealed Cell Valve Regulated Battery Types to be used.
For EN compliance the supplied current needs to be supported by the battery for required stand by
time.
