D9000/D7000 Series Operation & Installation Manual
Page 63
74-07692-000-C 4/97
Standby Battery Calculation for
NFPA 72 Fire Alarm Applications
Current Chart First
See the
Current Rating Chart for Standby Battery
Calculations for totals B and C used in the formulas
below. When connecting two batteries, use either
the D122 Dual Battery Wiring Harness or the D8132
Battery Charger Module.
Central Station or Local Systems
Central Station or Local Systems require 24 hours
of standby plus 5 minutes of alarm operation at the
end of the 24 hour period. A single battery is
sometimes adequate for Central Station Systems,
but you must install two batteries to meet the basic
standby requirements for a Local System
installation. You must use battery ampere hour (Ah)
calculations to verify compliance. The following
formula includes the calculation for 5 minutes of
alarm operation at the end of the 24 hour period, as
well as a 10% contingency factor which allows for
depletion of battery capacity with age.
Central Stations or Local Systems Ampere-
Hour Calculation Formula
Total B
Hours Total C
Hours
Contingency Total Ah
( ________ x24 ) + ( _______ x .083 ) + 10%
= ______
Total Ah requirements must not exceed Ah capacity
of batteries:
Two D126 Batteries = 14 Ah
Remote Station or Auxiliary Systems
Remote Station or Auxiliary Systems require 60
hours of standby plus 5 minutes of alarm operation
at the end of the 60 hour period. A D8132 Battery
Charger Module with additional batteries installed
in a separate D8109 or D8108A enclosure may be
required in the system to meet the basic standby
requirements for a Remote Station or Auxiliary
System installation. You must use battery ampere
hour (Ah) calculations to verify compliance. The
following formula includes the calculation for 5
minutes of alarm operation at the end of the 60 hour
period, as well as a 10% contingency factor which
allows for depletion of battery capacity with age.
Remote Station or Auxiliary Systems Ampere-
Hour Calculation Formula
Total B
Hours Total C
Hours
Contingency Total Ah
( ________ x60 ) + ( _______ x .083 ) + 10%
= ______
Total Ah requirements must not exceed Ah
capacity of batteries:
Two D126 Batteries = 14 Ah
Household Fire Warning Equipment
The Household Fire Warning Equipment Standard
requires 24 hours of standby plus 4 minutes of alarm
operation at the end of the 24 hour period. You must
use battery ampere hour (Ah) calculations to verify
compliance. The following formula includes the
calculation for 4 minutes of alarm operation at the
end of the 24 hour period, as well as a 10%
contingency factor which allows for depletion of
battery capacity with age.
Household Fire Ampere-Hour Calculation
Formula
Total B
Hours Total C
Hours
Contingency Total Ah
( ________ x24 ) + ( _______ x .067 ) + 10%
= ______
Total Ah requirements must not exceed Ah
capacity of batteries:
Two D126 Batteries = 14 Ah
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