FT2GAS
Gaseous Extinguishing System
Rev No. 1.3
41
Typical
I
A
calculations:
Items
Qiescent
Current
(mA)
Alarm
Current
(mA)
Qty
Total Alarm
Current (mA)
FT2GAS
75
250
1
250
Local Control Station (LCS)
0
60
3
180
“Fire Alarm / Do Not Enter” Sign
0
95
3
285
“Fire Alarm / Evacuate” Sign
0
95
3
285
“System Inoperative” Sign
0
95
3
285
3A Gas Discharge for 1 min
0
50
Optional Tone / Voice Sounders
0
135
6
810
Total Load current (mA)
75
1995
C20, Required Battery Capacity =
=
11.15
Ah
Battery Charger Calculations
Battery charger Ah required for 96 hours=
(5xI
Q
)
+ F
c
(0.5xI
A
)
=
(5x0.075) + 2(0.5x1.145)
=
1.52
Ah
Battery charging current required =
=
1.52/(96x0.75)
=
21.11
mA
1.2[(0.2(1.995x0.5+0.05)]
,where
η
is efficiency of
battery manufacturer typically
75%-85% (BB Battery)
η
×
Q
T
Required
Ah
Charger
Battery
Therefore, a battery capacity close to 11Ah battery or next higher with a battery charging current of
21.11 mA would be sufficient for this example.
Standard FT2GAS is equipped with 5.5 Amp switch mode power supply and space for 12 AH SLA
batteries.
