User Manual of WFCO WF-8900-AD-MBA Series Main Board
wfcoelectronics.com
warranty@wfcoelectronics.com
GENERAL INFORMATION
WF-8900-AD-MBA Series Main Board Assembly Safety Features
AUTOMATIC COOLING FAN
The cooling fan in the WF-8900-AD Series Power Center is incremental and is controlled by the current drawn out of the converter to the applied load. The on-board microprocessor increases fan speed as the total load increases and decreases fan speed as the load decreases. Unlike traditional temperature-controlled fans, the load-controlled fan provides better component cooling by avoiding temperature spikes which can lead to premature component failure.
OVER-TEMPERATURE PROTECTION
If the internal temperature of the converter exceeds a critical point, it will shut down. This protects the unit from excessive heat that may damage sensitive components. The unit will restart once the temperature inside has dropped.
ELECTRONIC CURRENT LIMITING
In the event that the output current exceeds the maximum rating for the WF-8900-AD Series Power Center converter, the output current will remain constant, but the output voltage will begin to drop. If this occurs, the unit will recover once loads are reduced.
SHORT-CIRCUIT PROTECTION
Should a short circuit occur in the RV, the WF-8900-AD Series Power Center converter will drop the voltage output to zero volts. If the short-circuit condition is removed and no other fault conditions are detected, the converter will resume normal operation. However, short-circuit conditions are dangerous, and an RV will require inspection by a qualified service technician.
CIRCUIT PROTECTION
WF-8900-AD-MBA Series Main Board Assembly Fuses and Breakers
REVERSE BATTERY PROTECTION
The WF-8900-AD-MBA Series Main Board Assembly will charge the 12-volt House battery if installed. A battery DOES NOT have to be installed for WF-8900-AD-MBA Series Main Board Assembly to operate. When a battery is installed, two reverse polarity fuses protect the MBA circuitry. The fuses are located along the left-center edge of the DC fuse board below the VCC+ lug. Refer to Figure 1 below. This feature prevents permanent damage to the MBA from a battery connected into the circuit backwards. In addition to protecting the MBA, the reverse polarity fuses are the main connection between the MBA and the DC fuse board.
The fuse values and quantity vary depending on which WF-8900-AD-MBA Series Main Board Assembly you have. Refer to the table below.
- WF-8935-AD-MBA – 35A (1)
- WF-8945-AD-MBA – 30A (2)
- WF-8955-AD-MBA – 40A (2)
- WF-8965-AD-MBA – 20A (4)
- WF-8975-AD-MBA – 20A (4)
The circuit fuses and the Reverse Battery Protection fuses should be replaced with ATC or ATO automotive type fuses such as:
- Littelfuse type 257
- Bussmann type ATC
DC FUSE BOARD
Figure 1
OPERATIONAL FEATURES
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.
THREE-STAGE SMART CHARGING
n order to maximize battery life, 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 are 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 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 maxi-mum 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 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 out-put voltage will not rise until the load current 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.
FLOAT MODE
The third mode of charging is what is called the “float” charge. This mode is designed to provide a “trickle charge” to the battery after the system observes no significant variations in current draw over a long period of time. When in “float” mode, the voltage will reduce from 13.6V to 13.2V and supply the “trickle charge” which helps to preserve the life of the battery while keeping it charged and ready for use. A change in DC current will cause the converter to exit the mode and return to the Absorption mode and then to Bulk mode if required.
Figure 2
NOTE: for a detailed explanation of the charging modes, please refer to our publication Theory of Operation, document #AD-TD-0001-0.
LITHIUM TWO-STAGE SMART CHARGING
The two-stage “smart” charger continuously measures the battery voltage output and regulates the amount of charge using two modes of operation: Bulk and Absorption mode.
2-STAGE CONVERTER VOLTAGE OUTPUT MODES
Understanding output voltages of a two-stage converter.
Figure 3
BULK MODE
This mode is designed with two purposes in mind. First, to quickly restore the energy back into the battery. Second, to ensure the lithium cells inside the battery remain balanced. This is accomplished by boosting the output voltage to 14.6 VDC and allowing the maximum current to flow as required by the loads.
The bulk mode stage could last anywhere from one to four hours based on the battery and load current which is being used. For a full battery, the bulk stage has a minimum time requirement of one hour, which allows the lithium cells inside the battery the time required to “balance”.
For an empty battery, the bulk stage has a maximum time requirement of four hours. If your application requires longer than four hours (such as a larger battery bank > 200 Ahr), a simple cycling of power will reset the timers.
As the energy is restored into the battery, the DC system voltage will climb and the current from the converter will decrease. If the total amperage draw from the converter reaches a preset point (within the one-to-four-hour timer), the converter is designed to drop out of bulk mode.
ABSORPTION MODE
This mode is designed with one purpose in mind. This purpose is to provide a safe operating voltage for all loads in the RV. This is accomplished by reducing (from bulk mode) the output voltage to 13.6 VDC and remaining at this voltage until the power is cycled to the converter.
The absorption mode stage is the default or normal mode of operation, which has no timer associated with it. In this mode an output of 13.6 VDC is provided to the DC circuits in the RV.
This voltage has a long-term history as the acceptable voltage for all loads in the RV, and should not place undue stress (nor reduce the longevity) of the lights and appliances in the RV. This is not to say that all loads will have an issue with a constant higher voltage; however, some loads may have an issue. Please refer to the individual manufacturer’s specifications for acceptable operating voltage range of the connected load.
TROUBLESHOOTING INSTRUCTIONS
Troubleshooting the WF-8900-AD-MBA Series Main Board Assembly
Refer to the Troubleshooting Guide for the WF-8900-AD-MBA Series Main Board Assembly (Figure 4 on page 9).
CONVERTER OUTPUT VOLTAGE
Before checking the WF-8900-AD-MBA Series Main Board Assembly output voltage, disconnect the battery cables at the battery. Make sure the converter is plugged into an AC source (105-130 Volts). Check the converter output voltage at the battery with a voltmeter. Place the meter probes on the disconnected battery cables; place the Positive (red) meter probe on the + Positive battery wire and place the Negative (black) meter probe on the – Negative wire on the battery cable. Be sure you have good connections at the cables. If the voltage reads 13.6-14.6V the converter is functioning properly.
If the converter output voltage at the battery reads 0.0 VDC, or if the battery is not charging, check for an open in-line fuse in the battery wire circuit. One may have been installed by the RV manufacturer. Also check for loose wiring connections.
DC REVERSE POLARITY (FUSES)
If there is no DC output coming from the WF-8900-AD-MBA Series Main Board Assembly converter section, first check the reverse polarity fuses on the fuse board. Then, visually inspect the fuses for any breaks in the fuse element. If no breaks are found, use a continuity tester to check for continuity. If the reverse polarity fuses are blown, it means the RV battery was accidentally connected in reverse, either at the battery or at the converter. Investigate the connections and reconnect the cables properly. Replace the fuse with the same type and samperage rating as the original.
IMPORTANT: These fuses protect the converter from damage if the RV battery is accidentally connected in reverse. A reversed battery connection, even if for only a second, will cause these fuses to blow.
If the above checks have been made but the converter output still reads 0.0 VDC, the converter is not functioning properly. Contact the Arterra Distribution Power PROs at 1 (877) 294-8997.
AC REVERSE POLARITY (AUDIBLE ALARM)
This power center is equipped with an AC REVERSE POLARITY PROTECTION feature. Should the incoming AC neutral wire and lead wire be connected backwards at the power center, an alarm located in the power center enclosure will sound. This alarm will continue to sound until the AC wires are connected correctly.
Figure 4
Should it be determined that the WF-8900-AD-MBA Series Main Board Assembly needs to be replaced, removal of the Main Board Assembly Is a simple process.
REPLACING THE CONVERTER SECTION (MBA)
Make sure no AC power is coming into the RV from either the Shore Power cord or an on-board generator. Remove and set aside the Reverse Polarity Fuses located on the fuse board to disconnect the converter section from the rest of the RV’s DC power.
PERFORM THE FOLLOWING STEPS
- Remove the door assembly by loosening the two screws located in the upper left and right corners. The screws are captive and will not fall out. Pull forward and outward on the door assembly to clear the case.
- In the upper left portion of the fuse board, loosen the NEG- lug (White wire) and the VCC+ lug (Red wire). Do not back the lug screws all the way out.
- Locate the tab at the bottom of the fuse board holding the board in place. Gently depress the tab allowing the fuse board to be pulled forward.
- With the fuse board pulled slightly away from its mounting, pull the Red and White wires out of the lugs.
- In the AC section of the enclosure, locate the Black wire coming up from the converter in the lower section. As an extra precaution, MAKE SURE THE CONVERTER BREAKER IS IN THE OFF POSITION. Remove the wire from the breaker. NOTE: this wire has a metal pin terminal on the end inserted into the breaker. Remove and position out of the way any wire connected to the pigtail.
- Locate and remove the converter’s Green Ground wire attached to the AC Ground bar on the left side of the compartment. In a similar fashion, locate and remove the converter’s White Neutral wire attached to the AC Neutral bar at the top of the compartment.
- In the converter compartment, remove the two screws at the front of the MBA holding it in place. Slide the MBA forward routing the wires through the slots in the case until the MBA clears the enclosure.
If the MBA is being returned under a warranty claim, follow the packaging instructions in your warranty claim packet. When installing a replacement MBA, reverse the order of steps 1-7.
Figure 5
GENERAL COMPLIANCE INFORMATION
WF-8900-AD-MBA Series Main Board Assembly Safety Features
UL
The WF-8900-AD-MBA Series Main Board Assemblies are UL-Listed, and cUL-Listed (Canadian).
FCC COMPLIANCE CLASS B
NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy, and if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense.
INSTALLATION INSTRUCTIONS
Installing the WF-8900-AD-MBA Series Main Board Assmebly
MOUNTING THE CONVERTER SECTION (MBA)
Refer to Replacing the Converter Section (MBA) on page 10 for complete removal and installation instructions.
CONSUMER LIMITED WARRANTY
for WFCO Electronic Products
WFCO extends, to the original owner, a Two-Year Limited Product Warranty. This warranty is in effect from the date of original purchase for a period of two years. This limited warranty is extended specifically for and is limited to Recreational Vehicle application and is only valid within the continental United States, Alaska, Hawaii and the Provinces of Canada. WFCO warrants, to the owner, that its products are free from defects in material and workmanship under normal use and service based on its intended use and function. This warranty is limited to the repair or replacement, at WFCO’s discretion, of any defective parts or defective assembly. Any implied warranties of merchantability or fitness for intended use are limited in duration unless applicable State Law provides otherwise. You may have other rights as specified by each individual state.
EXCLUSIONS AND LIMITATIONS
The OEM warranty specifically does not apply to the following:
- Any WFCO product that has been repaired or altered by an unauthorized person
- Any damage caused by misuse, faulty installation, testing, negligence, accident or any WFCO product installed in a commercial vehicle
- Any WFCO product, whose serial number has been defaced, altered or removed
- Any WFCO product, whose installation has not been in accordance with the WFCO written instructions
- Any consequential damages arising from the loss of use of the product including but not limited to inconvenience, loss of service, loss of revenue, loss or damage to personal property, cost of all services performed in removing or replacing the WFCO product. Specifications are subject to change without notice or obligation.
- Any WFCO Electronics products sold through unauthorized Internet sources (Example: eBay) will be excluded from all warranty coverage offered by Arterra Distribution / WFCO.
CONSUMER WARRANTY CLAIM PROCEDURE
Upon determination and validation by an authorized OEM dealer that a WFCO product has a defect, a Return Goods Authorization (RGA) number will be required before the product can be returned. The RGA number can be requested by completing the Warranty
Information Fax Sheet and appropriate Troubleshooting Form found at wfcoelectronics.com. Once these forms have been completed, email the forms along with Proof of Purchase to warranty@wfcoelectronics.com or fax the three documents to the Warranty Department at (574) 294-8698. After receipt of the forms, an RGA number will be issued. This number shall appear on all correspondence with warranty service. Upon validation of the warranty, WFCO shall replace the product with a like product. The RGA number shall be placed on the outside of the carton used to return the product for ease of identification. Do not mark directly on the product. The product must be packaged properly to avoid further product damage which could cause a non-warrantable condition.
WARRANTY ASSISTANCE
The consumer may contact the selling Dealer or OEM for warranty assistance. The consumer may also contact Arterra Distribution, exclusive distributor to WFCO Products at: (574) 294-8997 or Fax (574) 294-8698.
Dimensional Drawing
Figure 6
ARTERRA DISTRIBUTION
(877) 294-8997
wfcoelectronics.com
WARRANTY
warranty@wfcoelectronics.com
Fax (574) 294-8698
Distributed by Arterra in the U.S.A. and Canada
Power PROs Technical Support
(877) 294-8997