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How To Tell If RV Converter Is Bad?

Lights flickering? Devices stopped working? Is your battery running out of juice? No, your RV is not haunted. Instead, it’s a lot worse: your converter has gone bad!

But what in the world is an RV power converter? A converter is what converts the AC power to DC power on your RV. It’s used when you’re hooked up straight to the grid or to a generator. And when it stops working, your RV no longer receives clean 12 VDC power.

Now the question is: how to tell if the RV converter is bad? A weak battery can have many causes. Here’s all you need to know about testing RV converters for faults and short-circuits!

What Does an RV Converter Do?

You may have heard of an RV converter. But what does it do?

Converters perform two essential tasks. The first task is to convert 120 V shore power into 12 V DC power for your appliances. Most appliances in your RV, such as the electronics aboard the RV itself, work on 12 V DC power.

But there’s another function your converter performs: charging the battery. When connected to shore power, the converter supplies constant 12 V DC power to the battery. This means your battery stays charged while you’re hooked up to the grid.

How Do I Know If My RV Converter Is Bad?

How To Tell If RV Converter Is Bad

Since you know what an RV converter does, the symptoms of a bad converter aren’t hard to not notice. There are three dead giveaways of a bad converter:

Your Appliances Aren’t Working or Are Fused

Since converters are responsible for stepping down the 120 VAC power to 12 VDC, failure to do so can malfunction appliances. For example, if the converter provides 120 VAC, then it’s like that they’ll blow a fuse, or a circuit breaker will get tripped.

Abnormal Light Flickering

One of the most common signs of a bad converter is flickering lights. Since the converter converts AC to DC, failure can lead to flickering lights. The lights flicker because they’re being provided with AC power and not DC. Of course, malfunctions in other equipment are also possible. But the lights are usually the first to show signs of this.

Batteries Losing Charge

Finally, if the batteries don’t seem to hold their charge as long, you know there’s something wrong with the converter. Now, of course, it could just be your battery. There are several reasons for a battery losing charge quickly, one of which includes age.

How Do I Test My RV’s Battery Converter Charger Step-By-Step?

If all else seems fine, but your RV’s battery doesn’t seem to maintain its charge, there are a few things you can do. Try these tests and check if your battery converter charger is working right:

Step 1 – Test The 120v Ac Terminals

First things first, check if your converter is getting the 120 VAC power it needs. Next, get a battery voltmeter and put the probes across the 120 VAC terminals. The voltage should be very high, ideally 120V.

You probably have a blown fuse or a tripped circuit breaker if the power isn’t reaching the converter. Additionally, your converter may have become disconnected from the rest of the RV.

Step 2 – Test the Battery Terminals

Now that you know whether the converter is getting power or not, it’s time to test the battery. Connect the voltmeter to the battery terminals properly. Connect the red wire to the hot wire of the battery and the black wire to the battery’s negative terminal.

Your battery should ideally read 14 VDC or somewhere around that. If that’s not the case, you know there’s something wrong with the converter.

Step 3 – Check the Other Outlets

If the coach battery converter charger relay is the issue, your lights and appliances shouldn’t be working either. The easiest way to do so is to check if the other appliances are working. Or, if you can’t plug in the appliances for any reason, take a reading at the light fittings or sockets.

Your voltmeter should read 14 VDC or around that much. If it doesn’t, then your converter charger is mostly the issue. If there is a reading at the sockets or light fittings, your battery is most likely the issue.

Step 4 – Perform Tests on The Solenoid

Your RV also uses a solenoid called a transfer relay switch. This is what connects the converter charger to the battery. If it doesn’t work properly, then the fault is neither in the converter nor the battery. The easiest way to check this is to disconnect all power from the converter and open up the solenoid case. Then, spray some electrical contact cleaner inside. Finally, close the case and connect it again.

If the battery charges fine this time, the issue was with the solenoid. Otherwise, leave it alone and perform the other tests.

Step 5 – Check the Transformer

Lastly, you’ll want to check the transformer. The transformer is what reduces the 120 V power to 12 V power. Set your voltmeter on the input terminals of the transformer. The input should read 120 V, and the output should read 12 V.

If the input doesn’t read 120V, you fault with the system somewhere before the transformer. Likewise, the transformer is faulty if the input has the correct reading, but the output doesn’t read 14 V.

How Can I Test the RV’s Converter’s Cooling Fan?

Your RV’s converter also has a cooling fan that keeps it cool as the converter is prone to overheating. You can test the fan by either running it and checking for movement or detecting a voltage. Next, place the voltmeter at the terminal on the converter where the fan is connected. It should give a decent reading of around 12 VDC, depending on how much voltage it’s rated at.

If it doesn’t, and you can’t see or hear any movement inside, your fan is faulty.

What Causes an RV Converter to Fail?

Now that we know how to fix faulty RV converters, here’s a bit of technical background on why they fail:

  • The most common cause is overheating. The converter produces a lot of heat. And without a proper cooling fan, the converter can overheat. This will cause the soldering inside to melt and resolidify when it cools down. And the components and the wires could get damaged.
  • Another common cause is a power surge. When the converter receives more energy than it can handle, it either gets fried or a fuse gets blown.
  • When you don’t get sufficient shore power, the converter fails to provide a steady 12 VDC to your appliances.


How Do I Test My RV Power Converter?

First, test, whether the converter is getting the required 120 VAC power. Then, check if the battery and your appliances are getting the desired 12 VDC power. Then, check the solenoid. Finally, test the transformer to see if it’s the culprit.

What Happens When an RV Converter Goes Bad?

It depends on which part went bad. You may experience flickering lights, blown fuses, tripped circuit breakers, or devices that don’t turn on. Additionally, your battery may stop holding charge since the converter is no longer charging it.

Is There a Reset Button on An RV Converter?

Yes, there is! And entirely, unfortunately, the reset button may stop working or may stay permanently on if the converter is bad.

Should RV Converter Fans Run All the Time?

RV converter fans should only run when the converter gets hot enough to trigger a sensor. If you find that your converter is running all the time, there are two possible scenarios. Either your fan or sensor is faulty, or the converter is staying hot all the time.


The thought of an RV converter going bad can scare newbies and professionals alike. This is because converters are so prone to going bad. And they often warrant either a visit to the local electrician or buying a new converter.

Luckily, you now know all about how to tell if an RV converter is bad. To recall, there are some obvious signs, such as flickering lights, blown fuses, and a weak battery. But the problem isn’t always as obvious. So, you can easily test the converter and the battery using nothing but a voltmeter.

Now that you know how to test the converter, it’s time to put your knowledge to the test!

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