WFCO Converter Not Charging Battery: Ultimate Best Test

If your WFCO converter is not charging your battery, there are a few things you can check out to see what the issue is. Having an RV battery operating and staying charged is important to you and your RV, so you are doing the right thing by looking into this problem.

Converters act as the charger for your RV battery. And when your battery is not charging, the first suspect is the converter. The thing is, most of the time, the converter itself does work, and the real issue is an underlying connection or break in the power connection to the house battery. The most common reasons a converter is not charging a battery are a weak wire connection or a bad battery. This post will work you through a few simple diagnostic tests to see what the issue really is and if it is indeed the converter not charging the battery, including:

  • Shore Power
  • Battery Connection
  • How To Test RV Converter
  • Circuit Breaker

Even though we are chatting about WFCO converters, most of the tips and tests below apply to most RV power converters. Regardless of the manufacturer, many of the modern converters today operate similarly with the same applications.

Table of Contents

Shore Power

The first thing to check for is your shore power. This may sound obvious, but there are times when I thought the issue was the converter, and it was really shore power.

Since an RV power converter works by taking the AC power and “converters” it to DC power, any issue with shore power may appear as the battery not charging.

Doing a quick test can confirm that your shore power is good and that the converter is getting the sufficient power it needs.

While plugged into shore power, use an appliance that only works on AC power; usually, a microwave is a good choice. This is a nice time to make a bag of pop-corn. If the microwave works perfectly and there are no issues with the power, then your shore power should be good, and we can move on to the next possible cause.


Next on the list for power supply is to check the battery and see its condition and connections. Any disruption or power flow to and from the RV battery will cause the converter not to charge. Whether you have a lithium or lead acid battery, the testing below will apply to all battery types.

There are a few things that can cause trouble with onboard batteries, so let’s take a look at the most common weak spots.


The first thing to check with your RV battery connection is the wire. Make sure that the wires are secure and not loose. Usually, it is a bigger wire size and will have a bolt or terminal connection. Your RV goes down the road and bounces a lot. This bouncing can easily loosen nuts or bolts that are holding the battery cable to the battery.  And with a loose connection, the RV converter cannot as the charger that your battery needs. 

 Check all your connections and ensure they are secure with good metal-to-metal contact.

Battery Terminal

Another common cause is battery terminal corrosion. Any dirt or corrosion on the battery terminal or wire itself can cause a weak connection and not allow the battery to charge.

Check all battery connections.

While at your battery, check and clean the connections. A wire brush or small piece of sandpaper can provide a good surface scraping to expose that shiny metal. The key is getting to bare metal and ensuring good metal-to-metal contact.


Our next step is to check the battery voltage and see if we have a bad battery or if the converter is not working. Since an RV battery can go bad, checking it before buying a new converter would be a good idea.

A 12 volt battery operates properly down to 12 volts and up to 13.4 volts. Now, you can overcharge a deep cycle battery, but most of the time, the RV converter doesn’t provide enough voltage to overcharge it. You will need to grab your voltage meter for our next test set.

Our goal for the next test is to see if we are getting the proper voltage from our WFCO converter. By doing this test, we can see whether the RV converter is providing the proper voltage.

How To Test RV Converter

Here is how you can test your RV converter to see if it works properly. The purpose of this test is to bypass the battery power and see what actual voltage the converter provides.

  1. Disconnect the Positive lead at the battery terminals and set aside. Make sure this is not touching any other metal or other terminal or wire.
  2. Turn off any battery-powered appliances in your RV. For a complete list, visit what a battery power in a travel trailer.
  3. Connect your volt meter from the Postive Lead (that you set aside) and the negative battery terminal. Are you getting 13.6 volts? If you are, your converter is working, and you likely have more of a bad battery issue.

If your volt meter gives you a reading below 13.4 volts, the RV converter does not provide the proper voltage to keep your battery charged. Per WFCO, if you are getting below 13.4 volts, the potential causes are:

  1. Check Circuit Breaker for a blown fuse
  2. Reverse Polarity Fuse may be blown
  3. Battery disconnect switch problems

Circuit Breaker

The RVs electrical system is located in your RV circuit breaker or fuse box. It is the power center of your RV.  Since the power converter gives DC power, we will focus on the fuses, whereas the AC breaker is for only 120V ac power. 

Blown Fuse

Check for a blown fuse. Fuses are labeled by amperage. For example, fuses can range from 5 amps to 40 amps. Since this situation is dealing with the main power from a battery, the likely culprit fuse would be a higher amperage fuse. Check the highest amperage in your fuse box to see if they are still intact and working.

Reverse Polarity Fuse

A reverse polarity fuse acts just like an inline fuse. Its main purpose is to protect your electrical system if you accidentally connect across the positive and negative terminals. If that does happen, the inline fuse will blow and protect your power system.

Check the reverse polarity fuse.

To check your fuse, set your voltage meter to “continuity.” Place each of the test leads on the posts of the fuse. You should hear that “beeping” sound, meaning there is a connection and the fuse is good. If there is no beeping or continuity, the fuse is blown and must be replaced.

Battery Disconnect Switch

Your battery disconnect switch controls the main battery cable and can be switched off to disconnect power from the battery.

Now, issues with this can cause problems in your RV. For the best information, visit battery disconnect switch problems. There is a complete post on how to look for a test of the issues associated with a disconnect switch.

Final Thoughts

An RV converter is basically a battery charger. If your WFCO converter is not charging the battery, there are a few tests to determine the cause. Before you go out and buy a new converter, you will want to check your shore power. A power converter issue may be a battery issue, so check your battery to ensure it is good. After those check out, you can test your converter using a volt meter for voltage to see if you are getting the specified 13.6 volts from WFCO. When all else fails, check your fuses to see they are not blown.