Determining The Batteries - Siemens FDA241 Technical Manual

Planning
4

Determining the batteries

4.4
42
Building Technologies
Fire Safety
Determining the batteries
If the aspirating smoke detector's power supply via the external power unit fails,
power is supplied via batteries.
Determining the required battery type
The battery capacity depends on the following conditions:
Buffer time required

Battery age

Country-specific specifications, as regulated in local regulations or European

provisions
The required battery capacity can be identified using the following calculations:

C
= Battery capacity
Battery
f
= Factor for the battery age
t
= Buffer time
Standby
I
= Internal current of the power supply unit
PSU
t
= Alarm time
Alarm
To achieve the system voltage of DC 24 V, two batteries must be connected in

series.
The buffer times specified in the table apply in the case of an operating

temperature within the range -5...45 °C.
The batteries are charged using the external power unit. The charging current

for the batteries depends on the battery capacity. You should therefore select
your external power unit to match the batteries' capacity.
WARNING
Switching batteries in parallel
Risk of explosion and fire
● Never connect batteries in parallel!
● If you need more power, you must use batteries with a higher capacity.
See also
 Battery FA2003-A1 (12 V, 7 Ah, VdS) [➙ 38]
 Battery FA2004-A1 (12 V, 12 Ah, VdS) [➙ 38]
 Battery FA2005-A1 (12 V, 17 Ah, VdS) [➙ 38]
A6V10334410_h_en_--
2015-09-29