Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. Today he discusses inverters and converters.
After taking my truck camper off my truck using 12v system with HappiJac motors installed, the 12v side of my inverter (WFCO 8725) stopped working. It was plugged into shore power and everything worked normally. All fuses on 12v side tested good. Batteries were solar-charged and full – 14.4v each. With the converter brain needed to run appliances on shore power, it’s hard to imagine the inverter simply died. Is there any light you could shine on this issue? Thank you. —Chuck
According to the model number you gave, the WFCO 8725 is a three-stage power center and charges the house batteries when plugged into a shoreline supply or generator, i.e., it’s not an inverter. According to the owner’s manual, the first stage is the bulk or charge mode that provides a fast higher voltage charge of 14.4 volts to the batteries to help break up sulfation. Next is the absorption or normal mode that supplies 13.6 volts of normal charge and power to the batteries and appliances. Then there is a float or trickle charge which is typically 13.2 volts that is designed for storage or when the 12-volt system is not being used.
According to the manual, it has four 12-volt fuses and slots to the left for three 20-amp circuit breakers and one main breaker. There is no reference to an inverter operation. So it’s basically just a house battery charger. It does not provide any 120-volt power to systems from the house batteries as an inverter would.
Testing the WFCO 8275
To test the WFCO 8275, they recommend removing the cables on the unit going to the battery and taping them to prevent them from touching anything. Make sure you are plugged into a 30-amp source with 120-volt power. With a multimeter, place the probe on the white negative output wire and then place the other probe on each of the fuses. They should read 13.6 volts. This will tell you the unit is working properly.
If you are getting a reading of 14.4 volts from your solar charging controller to the WFCO 8275, then the panels are working, as well. However, if you are not getting any battery power when not connected to shoreline power, I would suspect your house battery or batteries are the problem.
With the cables disconnected, test with a multimeter to see what voltage you get. It should be 12.6 volts. And keep in mind, if you are not connected to a 120-volt shore line or generator source, you will not get 120-volt power to appliances such as the roof air conditioner, refrigerator on 120-volt mode, and outlets inside your rig.
Test the batteries and let us know what you found.
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