Siemens FC700A - Manual (Page 54)

Emergency power supply
54
Siemens Building Technologies 007836_a_en_--.doc
Fire & Security Products 03.2004
23 Emergency power supply
23.1 Specifying battery capacity
23.1.1 Battery rated capacity
– The battery rated capacity is based on the discharge over a period of 20 hours
– Faster discharge causes a loss of capacity:
Discharge over 12-hour period: 9% loss (K = 1.1)
23.1.2 Ageing of battery
– With increasing age, the battery suffers a loss of capacity
Allow a safety factor for ageing
(Total quiescent current y 1.25 or battery capacity y 0.8)
> 24h in conformity with DIN VDE 0833, part 2, no safety factor is necessary
23.1.3 Calculation
Battery capacity must be calculated individually!
Formula: Ah = A x h x 1.25 (poss. x K)
Ah
= Battery capacity in Ah
A = the sum of the quiescent current for all modules
h = Required operating period in hours
1.25 = Safety factor for ageing
K = Capacity loss if discharge is over considerably less than 20 hours
23.2 Capacity values for standard configurations
Battery capacity requirement for
Configuration Quiescent current
12h 24h 72h
128 detectors addressable 7outputs 235mA 3,8Ah 7,0Ah 16,9Ah
16 collective lines 7 outputs 315mA 5,1Ah 9,4Ah 22,6Ah
Notes:
– Equipped with 1 control terminal B3Q700
– Discharge over a 12-hour period, 9% loss of capacity taken into account
– Factor 1.25 for ageing taken into account at 12h and 24h (72h without safety
factor)
– Without remote transmission equipment
– Only quiescent current taken into account