Emergency power supply
23 Emergency power supply
23.1Specifying battery capacity
23.1.1Battery 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 | 9% loss (K = 1.1) |
23.1.2Ageing 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
23.1.3Calculation
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
23.2Capacity values for standard configurations
Configuration |
| Quiescent current | Battery capacity requirement for | ||
| 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
–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
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Siemens Building Technologies | |
Fire & Security Products | 03.2004 |
