Document No: LT0255
F3200/NDU AS4428.1 Installation Manual
Configuring a FIP
Issue 1.22
5 July 2016
Page 4-5
EXAMPLE BATTERY/CHARGER CALCULATIONS (CONTINUED)
An external 24V bell drawing 30mA.
A PA0765 T-GEN 50 (Tones and Fault Monitoring) with a 16W speaker load.
Calculate the required battery capacity and check the power supply capacity.
Steps
1.
The quiescent load (Iq) for the mains fail situation is:
130mA (FIP including one 8ZM)
+ 82mA (second 8ZM, all AZCs enabled)
+ 4mA (third 8ZM, basic current only)
+ 4 x 10mA (third 8ZM, current for 4 AZCs)
+ 42mA (detector current)
+ 6mA (8RM, supervision enabled)
+ 42mA (PA0765 T-GEN 50 with Fault relay enabled)
346mA
Say Iq = 0.35A for mains off.
The quiescent load for mains on is Iq plus the door holders (In = 0.35A) i.e. 0.70A. (It
was purely coincidence that Iq = In).
2.
Say, for example, that the 2 zones in alarm can, at most, turn on 3 of the 5 module
relays plus the External Bell, the T-GEN 50 Warning System and the Anc 1 load.
The alarm load for 2 zones in alarm is therefore:
275mA (FIP including 1 8ZM, 2 zone alarm, MAF relays)
+ 82mA (second 8ZM, quiescent only)
+ 44mA (third 8ZM, quiescent only)
+ 42mA (detector current)
+ 6mA (basic 8RM current)
+ 3 x 11mA (3 relays on 8RM)
+ 3 x 50mA (loads on 3 relays)
+ 100mA (Ancillary 1 relay load)
+ 30mA (Bell load)
+ 704mA (T-GEN 50 alarm load of 16/50 x 2.2A).
1466mA
Say Ia = 1.47A (the door holders are switched off in alarm).
3.
Cap (5 hr) = 5 x 0.35 + 1.47 Ah = 3.22 Ah
4.
Battery charger current required is:
Ia (1.47A) is greater than Iq + In, (0.70A), therefore:
Ic = 1.47A + (3.22/24) x 1.25 = 1.64A (where the 1.25 allows for charging efficiency e
of 0.8) i.e. 3A is sufficient.
5.
Battery capacity
Cap (24 hr) = [(24 x 0.35) x 1.47] x 1.25 = 12.3Ah. (where the 1.25 allows for battery
deterioration over lifetime to 80% of new value).
Two 12V, 17 Ah sealed batteries would be sufficient.
