Xtralis VESDA VLI - Page 30

VESDA VLI Product Guide VESDA by Xtralis
24 www.xtralis.com
3.2.8 Specify Backup Battery
In the event of a mains power supply disruption, the VLI detector runs on a backup battery. The size
of the battery is determined by:
l local codes and standards
l the total power required by the system
l back up time required
l allowance for reduction in capacity with age
l expected temperature variations
Note: It is recommended that batteries be inspected and changed as per manufacturer’s
specifications or as per local codes and standards.
To facilitate the calculation of the backup battery size, a Battery Calculation Sheet is included below.
Table 3-2: Calculating the size of backup battery
Equipment Normal loads@ 24 V DC Full alarm load @ 24 V DC
Load mA Qty Total Load mA Qty Total
Detector 340 390
Remote Display 90 110
Remote Programmer 50
(backlight off)
110
(backlight on)
Hand-held Programmer 50
(backlight off)
110
(backlight on)
System Relay Module 60 105
Other 24V Loads Total
mA
Total
mA
X X
Standby Hours Alarm Hours
=
Standby Capacity Alarm Capacity
Total Capacity =
Standby + Alarm
Divided by 1000 for
Standby Capacity
Multiply by battery
factor X1.25
Note: If monitored GPI terminals are connected to the power supply and configured for external fault,
the aspirator speed will be maintained for one hour after the loss of mains power, after which the
aspirator speed will be limited to 3000 rpm to conserve power.