WFCO WF-9800-AD Series, Operator'S Manual

5

AUTO-DETECT

This product includes the exclusive “Auto-detect” feature for the charging of batteries.  With this new 
technology, the power converter will evaluate the charging cycle of a battery, determine the type of 
battery being used, and then choose the appropriate charging program (profile) to provide for the 
best performance and maintenance of that battery. 
Because of the differences of Lead Acid, AGM and Lithium type batteries, a system that provides a 
charge to the battery or batteries must be able to accommodate the different charging requirements.  
With the use of the “Auto-detect” product, the charging requirement is able to be “detected” and is 
then automatically set for the type of battery being used.  For standard Lead Acid and AGM batteries, 
WFCO power converters still use the Three-Stage Smart Charging to effectively maximize battery life 
by monitoring through the different phases of the charge cycle.  On the other hand, Lithium batteries 
will prefer the use of only two stages when charging, and therefore the power converter will charge 
using the WFCO Two-Stage Smart Charging system.

LEAD ACID & AGM BATTERY THREE-STAGE SMART CHARGING 

In order to maximize battery life for lead acid and AGM batteries, it is best to charge batteries slowly, 
keep them topped off with a trickle-charge when the RV is not being used. The 3-Stage “smart”  
charger continuously measures the battery voltage output and regulates the amount of charge using 
three modes of operation; Absorption, Bulk and Float modes. 
All WFCO power converters have automatic three-stage switching power supplies. The converter  
senses which mode it needs to be in by checking the RV system voltage.

ABSORPTION MODE

The converter normally provides a constant target output voltage of 13.6 VDC (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. 

BULK MODE

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 VDC and 
a timer will start. Although the converter is outputting 14.4 VDC, 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 current is 
reduced, which happens naturally as the battery charges or if 12 VDC 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 
VDC for Absorption Mode. Lights that are powered from the output may change brightness slightly at 
that time.

OPERATIONAL FEATURES