PREMIER EX PLUS – OPERATION & INSTALLATION MANUAL
PAGE 16
DOCUMENT: GLT-MAN.115
ISSUE: 1 DATE: 22/8/05
AUTHOR: NRPJ
STAND BY BATTERY CALCULATION
In order to calculate the standby battery size required, the following formula can be used:-
Battery Size (Standby time in Amp Hours) = 1.25 x [(T
ALM
x I
ALM
) + (T
SBY
x (I
QP
+ I
QZ
))]
Where:
T
ALM
= Maximum time in hours required for the alarm [½ hour is most common time]
I
ALM
= Total Alarm Current in amps for all alarm devices connected to the alarm circuits
T
SBY
= Standby time in hours for the system after mains failure [normally 24, 48 or 72 hr]
I
QP
= Quiescent current in amps of control panel in fault condition [because of mains failure]
I
QZ
= Quiescent current in amps of all detection zones. Eg Ion detector 0.00005 Amp
(50 µA) , Optical Detector = 0.0001 Amp (100 µA)
T
BOT
= Time in hours the bottle output is active [Output switches off after 3 minutes]
I
BOT
= Current in amps taken by the bottle output (solenoid etc)
Typical Example:
A system comprises of 2 ionisation detectors on zone 1, 2 optical detectors on zone 2, 1
sounder on 1
st
stage snd, and 1 sounder (different tone) on 2
nd
stage sounder. The solenoid
will use 1 amp when active. The required standby is 24 hours. It will need to operate in alarm
for ½ hour before operating the bottle.
Calculate the battery size required.
T
ALM
= 0.5 Hr
I
ALM
= 0.025 + 0.085=0.11A [For 1 sounder @ 25 mA. Most alarm Devices show their
operating current]
T
BOT
= 0.05Hr
[the bottle output switches off after 3 minutes]
I
BOT
= 1 A
T
SBY
= 24 Hr
I
QP
= 0.085A [Current drawn during mains fail, with internal buzzer active]
I
QZ
= 2x50 µA + 2x100 µA =0.0003A [The quiescent current for an ionisation detector is 50
µA & 100 µA for an optical]
Therefore using the equation:
Battery Size (Standby time in AHr) = 1.25 x [(T
BOT
x I
BOT
)+(T
ALM
x I
ALM
)+(T
SBY
x (I
QP
+ I
QZ
))]
Battery Size (Standby time in AHr) = 1.25 x [(0.05 x 1) +(0.5 x 0.11+ (24 x (0.085 + 0.0003))]
Battery Size (Standby time in Amp Hours) = 1.25 x [0.05 + 0.055 + (24 x 0.0853)]
Battery Size (Standby time in Amp Hours) = 1.25 x [0.105 + 2.047]
Battery Size (Standby time in Amp Hours) = 1.25 x 2.152
Battery Size (Standby time in Amp Hours) = 2.69 Amp Hours
This system would require a minimum of 2.69Ah batteries, so we would recommend using
3Ah batteries OR 7Ah batteries.
