WFCO WF-8855E, Operator'S Manual

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5
CIRCUIT PROTECTION
WF-8855E Series Converter-Charger Fuses
DC Fuses (12 Volts)
The DC fuse receptacle on the rear panel of the WF-8855E Series Converter-Charger has space
for 2 (two) Reverse Battery Protection fuses (see Figure 1 above). These fuses should be replaced
with ATC or ATO automotive type fuses, such as Littelfuse type 257 or Bussmann type ATC.
• WF-8855E - (2) 35A
OPERATIONAL FEATURES
Converter Operation Modes
Three-Stage Smart Charging
The three-stage “smart” charger continuously measures the battery voltage output and regulates
the amount of charge using three modes of operation; Absorption, Bulk, and Float. See Figure 3
below.
The converter normally provides a constant target output voltage of 13.6 volts (nominal) to
power all the branch circuits. However, it is current limited, and if the output (load) current
reaches its maximum, the output voltage will drop as necessary to hold the converter’s
maximum output current level (the amperage rating) without exceeding it.
If the output current reaches its maximum (normally caused by a discharged battery), this will
cause the converter to go into Bulk Mode, which means the target output voltage will change
to 14.4 volts and a timer will start. Although the converter is outputting 14.4 volts, you will not
be able to read that on a voltmeter due to the voltage-current relationship. From the paragraph
above, as load current increases, output voltage decreases. The actual output voltage will not rise
until the load is reduced, which happens naturally as the battery charges or if 12-volt appliances
are turned off.
Bulk Mode will be maintained until the current draw drops to approximately five amps, or
until the timer reaches four hours (whichever happens first). Then the target output voltage is
changed back to 13.6 volts for Absorption Mode. Lights that are powered from the output may
change brightness slightly at that time.
After the output has been maintained at 13.6 volts (Absorption Mode) for 44 hours, the
converter will change to Float Mode with an output of 13.2 volts. This output may then reset to
Absorption Mode (13.6 volts) if power is interrupted, or to Bulk Mode (14.4 volts) if the output
current limit is reached.