Operating instructions

FC Operation & Maintenance Guide (20 & 25 Amp)
11
5.3 Adjusting Alarm Voltage Levels
Three alarm adjustments are possible: charger failure alarm, low battery voltage alarm and high
battery voltage alarm. The location of the adjustment potentiometers is shown in a drawing at the
end of this guide. Use an external precision voltmeter connected directly to the charger's output
terminals.
To adjust the alarms, use an external adjustable DC power supply capable of providing up to 1/2
of an amp and an infinitely variable range of 10 to 50 volts.
De-energize the charger, disconnect the battery and connect the power supply's output leads to
the charger's FC output terminals, being careful to observe correct polarity. Turn on the power
supply. Verify on the external meter that polarity is correct.
Low battery alarm: Adjust the power supply to the desired alarm level. Turn the alarm pot
counter-clockwise one revolution or so to increase the alarm voltage point.
Wait until the alarm activates (about one minute). Now slowly turn the
adjustment pot clockwise until the alarm light shuts off. This will be the
voltage at which the adjustable power supply is set.
Charge fail alarm: Set this alarm using the same procedure as the low battery voltage alarm.
High battery alarm: Adjust the power supply to the desired level. Turn the alarm pot counter-
clockwise one turn or so to reduce the alarm voltage to a low value. Now
slowly turn the adjustment pot clockwise until the alarm light turns on. This will
be the voltage at which the adjustable supply is set.
5.4 Factory-Set Alarm Voltages
Chargers set for lead-acid battery
12 volt 24 volt 32 volt
Low battery alarm voltage 11.0 22.0 30.0
High battery alarm voltage 16.0 32.0 40.5
Charge fail alarm voltage 12.5 25.0 34.0
Chargers set for nickel cadmium battery
12 volt 24 volt 32 volt
(# cells), low battery alarm voltage (10) 13.0 (19) 25.0 (25) 32.5
(20) 26.0 (27) 35.1
(# cells), high battery alarm voltage (10) 16.5 (19) 31.0 (25) 40.8
(20) 32.6 (27) 44.0