MTech MA-1000, Installation & Operation Manual

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2.3 Calculating Maximum Current Draw and Battery Backup Requirements
This section will assist you in determining the maximum system current draw and standby battery
needs for your installation. Follow the steps below to determine the current draw and standby
battery requirements. Appendix B
—MA-1000 Current Draw/Battery Backup lists the standby and
alarm current draw for the panel. Total standby and alarm Current is determined by multiplying the
quantity of items by its current draw. To quickly determine maximum system current draw, perform
the following computations:
Download the “Backup Calculation.xls” file from
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Fill in the quantities of conventional detectors, addressable detectors and devices.
Fill in the quantities and current draw of the Notification Appliances or auxiliary-powered devices for
each output from the manual for each specific device.
Fill in the total quantities of detectors and modules. The detectors and modules total alarm current
is determinate by estimation method, under the hypothesis that 5% LED will be ON.
The required battery capacity is determined according to equation
Cb >= (Isb* Tsb + Ia*Ta)*1.1
Where:
Cb- required battery capacity, Ah
Isb
– standby current, A
Tsb
– supervisory time, 24 or 60 hours
Ia
– alarm current, A
Ta
– alrm time, 5 min (0.0833 hours)
1.1
– safety factor.
Make sure the total alarm current you calculated (including current for the panel itself) does not
exceed 4.5 Amps. This is the maximum alarm current allowable.
Calculation example is shown in the following table (1-2).