F3 Series Charger Manual
8
battery. This is the normal charging position for all batteries, and the recommended charging position at
all times for Valve Regulated Lead Acid (VRLA) batteries.
BOOST
This voltage is slightly higher than the float setting. Boost slightly overcharges the battery in order to
ensure that all the cells of a battery are fully charged to the same voltage. Continued operation in boost is
not
recommended because the high charging voltage will cause battery electrolyte to boil away quickly.
This is a particular problem with VRLA batteries where there is no way to replenish lost electrolyte.
3.3
FLOAT/BOOST CONTROL
F3 chargers are equipped with one of the four following float/boost voltage control systems depending on
the configuration ordered:
FLOAT/BOOST front panel rotary switch
The charger will operate indefinitely in the mode that is selected. The AUTO position may be shown on
the front panel. If the AUTO position is locked out, the AUTOBOOST feature is not supplied.
AUTO/FLOAT/BOOST front panel rotary switch
When the selector switch is in the FLOAT or BOOST mode the charger will operate indefinitely in the
mode that is selected.
The AUTO mode selects automatic equalization of the battery. The charger determines when the battery
is in need of fast charging, and operates in the fast charge boost mode only until the battery is fully
charged. The charger determines state of charge by the measuring the amount of current drawn from the
output terminals. When the selector switch is in the AUTO position the charger will start in the boost
mode and stay there until current demanded drops below about 50% of the charger’s rated current. When
current demand increases to about 70% of the charger’s rated output the charger will resume operation in
the boost mode.
Please see the Appendix for a diagram of how the Autoboost system works. The AUTO setting eliminates
the need to periodically equalize the cells of a battery as the charger does this automatically.
The AUTO
position should not be selected when the continuous load on the charger is greater than about 50% of the
charger’s maximum rated current.
Manually initiated boost timer (either 0-24 hours or 0-72 hours)
When the timer is turned clockwise the charger will be in boost mode, where it will remain until the timer
returns to 0 hours. At the end of the selected time the charger will return to float mode.
Manually initiated boost timer plus AUTO/FLOAT/BOOST rotary switch
Selection of the AUTO position allows the charger to operate in the AUTOBOOST mode (described
above)
Selection of the FLOAT mode forces the charger to remain in the float mode
unless
the boost timer is
activated by turning past zero. If the boost timer is activated, the charger will revert to float mode after the
time selected on the timer expires.
Selection of the BOOST mode forces the charger into boost charge, where it will remain until BOOST is
deselected manually.
3.4
Alarm Indications
NOTE:
Chargers are equipped with a “dead-front” panel. Alarm LEDs are behind the dead front panel
and will be visible when they illuminate due to an alarm condition, or when the TEST button is pressed.
See Figure 3.5 for the location of LED indicators. Chargers with no alarms (alarms code “0”) have no
LEDs or test button.
