EP203 AUTOMATIC EXTINGUISHER PANEL
Approved Document No. DFU0002032 Rev 4 • EP203 AUTOMATIC EXTINGUISHER PANEL INSTALLATION MANUAL • Page 41 of 45
APPENDICES
A P P E N DIX 1 – Standby Bat t e ry Calcula tion Guide
The standby time of the EP203 panel after the mains has failed depends on the quiescent
loading of the panel, the alarm load of the panel and the capacity of the batteries.
Note : LPCB approved systems must use 7Ahr batteries (YUASA Type NP7-12).
To determine the capacity of batteries required for any given standby period, the following
formula should be used:
The multiplier 1.25 is present to account for lost capacity over the life of the batteries.
T = Amount of time required for the alarm
A = Total alarm current of panel sounders
SL = Total alarm current of solenoid
RT = Solenoid activation time
H = Number of hours standby required
P = Quiescent current of the panel = 40mA (0.040A)
Z = Total quiescent current of all zone devices
RSUs = Total quiescent current of RSUs
ESUs = Total quiescent current of ESUs
Exa mple:
The panel has detectors consuming a total of 1mA (0.001A), 5 RSUs each consuming 0.01A and
5 ESUs each consuming 0.005A.
In alarm, there will be a solenoid load of 1A with a solenoid activation time of 5 secs
(0.00139hrs), a conventional sounder load of 200mA (0.20A). The required standby time is 24
hours and the required alarm time is 0.5 hours.
Calculate the alarm capacity: ( T x A) + (SL x RT )
T = 0.5hrs; A = 0.20A; SL = 1A; R T = 0.00139hrs
The alarm capacity = (0.5 x 0.20) + (1 x 0.00139)
= 0.10139 Ahr
Calculate the quiescent capacity: H x ( P + Z + RSUs + ESUs)
H = 24hrs; P = 0.040A; Z = 0.001A; RSU load = 5 x 0.01A; ESU load = 5 x 0.005A
The quiescent capacity = 24 x (0.040 + 0.001 + 5 x 0.01 + 5 x 0.005)
= 2.784 Ahr
Therefore, battery capacity = 1.25 x [0.10139 + 2.784]
= 3.61 Ahr
Battery c apa c ity (in Ahr) = 1.2 5 x [ ( T x A) + (SL x RT ) + H x (P + Z + RSUs + ESUs) ]
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