Instruction manual

3-24
The self-discharge rate of batteries is approximately 3% per month when the storage temperature
is maintained at 20 degrees C (68 degrees F). The self-discharge rate will vary depending upon
temperature. Cooler temperatures cause the self-discharge rate to decrease. Warmer
temperatures cause the self-discharge rate to increase.
Calculating Backup Battery Requirements
It is necessary to calculate the current draw for battery backup requirement, The current
requirements depend on the system configuration and the optional modules installed. Battery
Backup current has two separate calculations that are added together. They are Standby Current
and Alarm Current.
The SAFEPATH
®
Power Supply generates 24 VDC at a maximum of 6
Amps. The sum of the currents from all modules, speaker circuits, and
Strobe NAC circuits, and Speaker Amp circuits (when SALL-15S are used)
determine the current output of the panel and cannot exceed 6 Amps. If the
SAFEPATH
®
Panel output current exceeds 6.0 amps, it is recommended that
strobe circuits be routed through an external power supply.
Backup Battery Worksheet
Worksheet for assisting in calculating battery backup is available as Appendix B.
Standby Current
Standby current consumes the largest part of the storage battery capacity. Table 3-4 represents
the Standby Current of the Dual-Circuit SAFEPATH
®
Panel using the test signal as the
supervision signal. Standby calculations can use the appropriate value from this table. The Dual-
Circuit SAFEPATH
®
Panel Models in this table contain the Power Supply (DCPS), Digital Voice
Module (MDX-2) and the listed amplifiers.
Standby current from any optional module used is listed in Table 3-5 on Page 3-26. These values
added to the Panel current complete the total Standby current for the panel
Standby Current Calculating Procedure
1. From Table 3-4 on Page 3-25, select the desired value of current from the proper Model.
2. From Table 3-5 on Page 3-26, select the standby current from all modules selected for the
panel and add them to the value of Step 1. (If multiple RMS-3, SPL and/or NACIM Modules
are used, calculate the standby current for each one.)
3. Multiply the results of Step 2 by the number of standby hours required. (i.e. 24 or 60). Record
this value as the Standby Amp-hours.
! Caution: