Siemens FS20 - Determining the Battery

Determining the compact stations
Determining the batteries and power supply
11
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Building Technologies
008843_v_en_
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Fire
Safety
2015
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12
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15
11.3.3 Determining the battery
Calculating the battery capacity
Determine the battery capacity with the following formula:
K
Batt
= (I
R total
* t
R
+ I
A total
* t
A
) * k
dis
* k
age
K
Batt
Battery capacity in [Ah]
I
R total
Sum of operating current of all consumers in quiescent condition [A]
I
A total
Sum of operating current of all consumers in alarm condition [A]
t
R
Desired emergency power supply duration in quiescent condition [h]
t
A
Desired emergency power supply duration in alarm condition [h]
(standard 0.5 h)
k
dis
Correction factor for discharge
● k
dis
= 1.1 with ≤12-hour emergency power supply duration. In the
event of a longer emergency power supply duration, the factor can
be omitted.
k
age
Correction factor for aging
● k
age
= 1.25 if the desired emergency power supply duration is ≤24
h (according to DIN VDE 0833, part 2). In all other cases, the
factor can be omitted.
Example
K
Batt
= ((I
R total
* t
R
) * k
dis
* k
age
) + ((I
A total
* t
A
) * k
dis
* k
age
)
For 12 h emergency power supply duration:
= ((0.9 A * 12 h) * 1.1 * 1.25) + ((3.5 A * 0.5 h) * 1.1 * 1.25) = 17.2 Ah
For 24 h emergency power supply duration:
= ((0,9 A * 24 h) * 1.25) + ((3.5 A * 0.5 h) * 1.25) = 29.2 Ah
For 72 h emergency power supply duration:
= (0.9 A * 72 h) + (3.5 A * 0.5 h) = 66.5 Ah