Tuesday, November 28, 2023


Ask Dave: When RV is plugged in to shore power, why isn’t house battery charging?

Dear Dave,
When my RV is plugged in to shore power it doesn’t charge the battery. Is there a fuse inside the charger? When I turn on power I hear the cooling fan turn on briefly. There’s power going in but nothing out. —Claire, 2017 Winnebago Minnie Winnie 25B

Dear Claire,
Your Winnebago Class C Minnie Winnie is equipped with a WFCO all-in-one distribution center that is located under the bed pedestal, according to the Winnebago 3-D parts documentation.

Distribution center with circuit breakers

This is a 30-amp distribution center that has circuit breakers for the 120-volt operations and 12-volt fuses for the systems that run off the house batteries. It also has a built-in 55-amp converter, which is the charging system for the house batteries.

Your Minnie Winnie also came standard with two 12-volt deep cycle batteries that are in the outside compartment on the passenger side of the rig next to the entrance door. The original batteries were NAPA group 24, which may not be there now as most house batteries will not be properly charged to prevent sulfation. The WFCO converter will recognize a low battery and initiate a 13.6-volt charge until the batteries register 12.6 volts and then will drop to a maintenance charge of 13.2 volts.

As batteries are drained of power, sulfation begins to coat the plates inside the battery. A multistage charge starting with a high voltage “bulk” charge breaks up the sulfation and then goes into a equalizing and float charge. You can test what your converter is doing by using a multimeter on the 12-volt DC setting. I would suggest starting with the unit unplugged and test the state of charge of your current batteries. Fully charged they should be reading 12.9-volts. Anything lower would indicate they are probably sulfated. Then plug the shoreline cord into a 30-amp source and it should be either 13.6 volts or 13.2 volts. If the voltage does not change from what the batteries read, then it verifies the converter is not working.

Check the circuit breaker

In this case, I would first check the circuit breaker on the distribution panel. You should see a dedicated circuit breaker for the converter. If that is in the on position, you need to verify the circuit breaker is good and the converter is getting 120-volt power that it will “convert” to 12-volt power for the battery. This converter is located on the bottom portion of the unit. From there, I would check the connection of the converter to the batteries. If all that checks out, the converter is bad and you should be able to replace just that part.

Note: Be very careful working around 120-volt power. Most of these tests should only be performed by a qualified technician. Testing the 12-volt power going to the battery with a multimeter is a test the average RVer can perform safely.

If your converter is providing 13.2 – 13.6 volts and your batteries are not holding a charge, then they are the problem, not the converter.

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Dear Dave,
My converter, Progressive Dynamics PD9130V Inteli-Power, only charges the two 6v lead acid, deep cycle house batteries. I wish it would charge both the house and chassis batteries. Are there any negative issues connecting a 3-amp Battery Tender to a 110v outlet on the RV to keep the chassis battery charged while the RV is connected to shore power? —Pablo, 2002 Fleetwood Bounder 31W

Read Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

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Dave Solberg
Dave Solberghttp://www.rv-seminars.com/
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. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.



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Left Coast Geek (@guest_212778)
11 months ago

I’ve had to replace the power converter in TWO WFCO 8955’s… The PD4655 is a direct dropin replacement, and has a multi-stage smart charger, the new ones can even be jumpered for Lithium Iron Phosphate batteries. Installation is as simple as disconnecting the batteries, ensure the RV is not plugged nito shore power, pull the WFCO cover (2 screws), remove the WFCO voltage converter (couple screws, 5 wires), install the PD4655 in its place (reconnect same 5 wires), hook battery up, plug in shore power, and test, install WFCO cover, done.

Cee (@guest_209088)
1 year ago

Another great assessment Dave. Thanks!

Greg (@guest_209057)
1 year ago

My 2005 Fleetwood Gearbox has a similar setup and I have found shore charging only occurs when the “Master” DC switch is on(removable Red handle switch).

Ron Seidl P.E. (@guest_209042)
1 year ago

Regarding the converter not charging the house batteries, I would also recommend that the user check the tightness of all the wiring connectors in the WFCO charger.

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