Installation guide

EN | 59
D9124 | Operation & Installation Guide |
Bosch Security Systems | 11/03 | 39352E
Appendix A: Determining Battery Requirements
A.2.2 Calculating D9142 24 VDC Battery Capacity
Requirements for Initiating and Indicating
Devices
Central Stations or Local Systems Require 24 Hours
Standby
To determine 24-hour standby battery capacity, first use
the column labeled Column B, AC Power OFF (refer
to Tables 24 and 25) to calculate the total 24 VDC
current required. Next, use the column labeled Current
(A) in Table 26 to select the row with the current equal to
or larger than your calculated total from the chart,
Column B. To the left of this current value is the
battery amp hour rating you need. This value already
factors in a 5-minute bell current of 3 A at the end of the
24-hour standby period. If your standby current is
greater than 1 A, subtract the current from the bell
current. For example, you require 1.294 A of standby
current so you need a 38 Ah battery, which recharges in
37 hours. The maximum bell current is (4 A to 1.294 A)
= 2.716 A of bell current.
60-Hour Standby
Battery A-Hours Current (A) Recharge Time (Hours)
7 0.030 12
12 0.105 12
14 0.135 12
17.2 0.183 14
24 0.286 18
36 0.467 27
38 0.497 29
Table 27: 60-Hour Standby
24-Hour Standby
Battery A-Hours Current (A) Recharge Time (Hours)
7 0.136 10
12 0.322 10
14 0.397 11
17.2 0.517 13
24 0.771 18
36 1.219 34
38 1.294 37
Table 26: 24-Hour Standby
Figure 28: Remote Station or Auxiliary Systems Ampere-Hour Calculation Formula
Total B Hours Total C Hours Contingency Total mAh
( ____________ x 60) + ( ____________ x .083) + 10% = _________
Remote Stations or Auxiliary Systems Require
60 Hours Standby
To determine 60-hour standby battery capacity use the
column labeled Column B, AC Power OFF (refer to
Tables 24 and 25) to calculate the 24 VDC current
required. Next, use the column labeled Current (A) in
Table 27 and select the row where the current is equal to
or larger than your calculated total from the chart,
Column B. To the left of this current value is the
battery amp rating you need. This value already factors
in a 5-minute bell current of 3 A at the end of the 60-
hour standby period.
Recharge batteries within 48 hours after the fully-
charged batteries are subjected to a single discharge
cycle.
Figure 27: Central Stations or Local Systems Ampere-Hour Calculation Formula
Total B Hours Total C Hours Contingency Total mAh
( ____________ x 24) + ( ____________ x .083) + 10% = _________