Operating instructions

FC Operation & Maintenance Guide (20 & 25 Amp)
10
6. Put the charger in the AUTOBOOST mode by partially discharging the battery, then removing
and restoring the charger's AC power source.
7. Allow the battery voltage to rise to the desired high rate charge level. Once at this voltage,
carefully turn the boost pot counter-clockwise until the charger ammeter suddenly drops to
approximately zero amps.
8. Charger is now adjusted. Replace paper dots and close front cover.
Chargers with timed boost
6. Turn timer knob to start high rate charging.
7. Allow the battery voltage to rise to the desired high rate charge level. The battery should be
discharged so that charger is producing between 60% and 100% of its rated current. Once at
the desired boost voltage, carefully turn the boost pot counter-clockwise until the charger
ammeter drops noticeably (to between 1/2 and 2 amps).
8. Charger is now adjusted. Replace paper dots and close front cover.
Alternative adjustment procedure using capacitor and load bank -- all chargers
The capacitor and adjustable load take the place of a battery, so you do not have to wait for
the battery voltage to increase or decrease to new output voltage levels. The time delays in the alarm
circuit, however, cannot be defeated.
Connect the capacitor in parallel with the output terminals, making sure that the polarity is
correct. Use the same general adjustment procedure as the "all chargers" section above;
setting changes, however, do not have to be made in small increments. For the float
adjustment, adjust the load bank so that the charger puts out about one amp. For the boost
adjustment, adjust the load bank so that the charger puts out about 80% of its rated current.
This high load causes AUTOBOOST chargers to switch to high rate charge.
5.2 Factory-Set Output Voltages
Chargers set for lead-acid battery
12 volt 24 volt 32 volt
Float voltage 13.3 26.6 35.5
Boost voltage 14.0 28.0 37.3
Chargers set for nickel cadmium battery
12 volt 24 volt 32 volt
Float (# cells), voltage (10) 14.3 (19) 27.2 (25) 35.8
(20) 28.6 (27) 38.6
Boost (# cells), voltage (10) 15.2 (19) 28.6 (25) 37.5
(20) 30.0 (27) 40.5