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Has Your RV Converter Gone Bad? Here’s How to Tell

The electrical system is the most important system in an RV. Without a properly functioning electrical system, the other systems and amenities that RVers love so much are useless. Want to take a nice hot shower after a day skiing? Forget about it. Need to flip on a couple of lights while changing? No way. Is your phone dead? Too bad. All these comforts we RVers take advantage of are rendered completely inoperable once our electrical system fails and our batteries won’t hold a charge.

how-to-tell-if-rv-converter-is-bad

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Let’s say you own a nice travel trailer that you use to escape city life on long weekends. You’ve just spent an epic three days on the river relaxing, fishing, and drinking beers with some of your closest friends. At the end of the trip you roll on home, park your rig in the driveway, and plug your trailer into shore power so that it’s all charged up and ready to go next weekend.

Fishing

But when you go to hitch up and roll out the following weekend, you find your batteries haven’t recharged from last weekend and your trailer is dead. Now you have to either rely on your noisy backup generator all weekend (if you have one), or just use your trailer as a spot to crash at night and not utilize any of its other features. Not the end of the world, but also not ideal.

So what gives?What could be causing this failure in your power system?

The first and primary suspect in this scenario is your RV converter. If your converter is bad, the whole system is bad. Keep reading to learn how to tell if your RV converter has begun to fail.

What Does an RV Power Converter Do?

The power converter in an RV is a crucial component in its electrical system. Its primary function is to, big surprise, convert power. But what does this mean? What power is it converting and why?

First, a quick review on the two types of power in an RV:

  • Alternating current: The larger, more power-hungry appliances in an RV run off of 120-volt alternating current (AC) power. RV furnaces, air conditioners, microwaves and water heaters typically all require 120V AC power to function.
  • Direct current: 12-volt direct current (DC) power takes care of the remaining power needs in an RV. Overhead lighting, USB chargers, water pumps and ventilation fans are usually operating off of 12V DC power. These appliances all require significantly less voltage to function than the larger, more powerful appliances in an RV.
Voltmeter

RV batteries store 12-volt DC power. When these batteries run low on charge, it is common practice that the RV is plugged into a shore power connection to recharge. But, a shore power connection supplies the RV with 120-volt AC power, a voltage of power that won’t be able to be stored in the RV’s battery bank. This is where the converter comes into play.

An RV converter takes in 120V AC power and alters the voltage, turning it into 12V DC power that can be stored in RV batteries. This converting and charging action leads some RVers to refer to converters as “battery chargers”. Keep in mind that a converter and an RV’s inverter are similar, but not the same.

The RV converter is wired into the electrical system midway between the shore power connection and the RV battery bank. This wiring ensures that all AC shore power has to pass through the converter before charging the batteries.

Signs that an RV Converter is Bad

With electrical systems, there can oftentimes be many different signs that a component has begun to fail, some more obvious than others. Even trained electricians and RV technicians can end up pretty stumped over a failing system if the cause of the problem is resulting in unpredictable and uncommon symptoms.

Luckily, there are some common signs that many RVers have reported experiencing when an RV’s converter has begun to fail. If you suspect your RV converter is going bad, keep an eye out for these warning signs:

  • The RV’s interior lights begin to dim shortly after being turned on
  • Your refrigerator doesn’t maintain a consistent temperature and/or the display flickers
  • The converter’s cooling fan isn’t turning on when the electrical system is in use
  • When connected to shore power, batteries overheat and/or begin producing a sulfuric smell

Some of these warning signs are more serious than others. Flickering and dimming lights should indicate that the converter and batteries need to be checked out. This examination should be done promptly, but these symptoms do not necessarily indicate an emergency situation.

Overheating and smelly batteries are a different case altogether. If you experience either of these situations, immediately disconnect your RV from shore power and open up doors to allow fresh, cool air inside.

Diagnosing Converter Problems

If you do suspect that your RV converter has begun to fail, there are a number of at-home tests that can be performed in order to figure out if the converter is in fact the issue.

To perform some of these tests, you will want to pick yourself up a digital multimeter and a one-handed circuit tester also known as a test light.

Digital Multimeters

Digital-Multimeters

Digital multimeters are an incredibly useful tool for diagnosing electrical issues. Electricians and RV technicians always have a multimeter close at hand and will often use them multiple times a day while working.

The “multi” in multimeter stands for multiple. Digital multimeter can measure multiple electrical properties in an electrical system. Voltage, wattage, electrical resistance, temperature, and continuity are all properties that can be measured and monitored with a multimeter. When I worked as an RV technician, I used my multimeter so frequently that it eventually had its own name, fictional backstory, and a special case in my toolbox. That thing was a life saver.

Digital multimeters can be easily purchased from your local hardware or electrical supply store. They range in price from $10 for cheap (but perfectly functional) models, to over $100 for professional, heavy-duty models with many useful and nuanced features.

Circuit Testers

A circuit tester, or test light, tests the voltage and continuity of circuits. Test lights are similar to multimeters but with less functions and capabilities.

Resembling a screwdriver, a test light is a tool that requires one hand to use. They feature a clear handle with a digital display, a pointed metal tip, and a long ground wire that terminates in a metal clamp. To use a test light, simply clamp the ground wire onto the negative terminal or wire of the circuit in question, and touch the metal tip to the positive terminal or wire in the circuit. The display of the tester will light up, usually in red, and display the voltage of the circuit.


WARNING: Building, maintaining, and diagnosing electrical systems can be dangerous if done improperly. If you do not trust your ability to safely go about RV converter troubleshooting, take your camper to your local RV technician for a diagnostic appointment.

Checking the Fuse Block

The DC fuse block in an RV is where 12V DC power is sent from the battery bank, before being distributed to all of the individual circuits in the RV. Each appliance, or appliance group will have their own circuit and corresponding fuse.

To test your fuse block, begin by removing all of the fuses. Reinsert the fuse on the circuit you are hoping to test; if you have been experiencing flickering lights, maybe you’ll be testing the circuit for the overhead lights.

Flip on your multimeter and set it to measure DC power. Touch the metal tip on the multimeter’s black (negative) lead to the negative terminal on the fuse block, and the tip of the red (positive) lead to the positive terminal on the circuit you are testing. With the fuse in place and the electrical system working properly, the multimeter should read in the 11-13.5 volt range. Anything outside of that range and your fuse block may be busted and need replacing. If the multimeter reads nothing, then the fuse is probably blown. In that case, grab a freshie and try again.

Checking the RV Converter Fan

An overheating converter will stop working pretty quickly if the cause of the overheating is not addressed.

RV-Converter-Fan

To check the cooling fan, plug your RV into shore power and hang out near the RV converter for a while. While connected to shore, the cooling fan should turn on periodically to cool the unit. If the fan remains off and the converter begins to feel hot to the touch, then this could be the cause of your DC power problems.

Checking Converter Fuses

In some instances, converters appear to be broken when in reality they simply have a blown fuse. You can check if your converter’s fuses have blown by using a test light.

Clamp the ground wire on the test light to one of the negative terminals in your battery bank. Locate the fuses on the RV converter and touch the tip of the tester to the small metal dashes at the top of each fuse. Each metal dash should light the tester up, and display a voltage in the 13-13.5 range.

For a visual aid on this process, check out this video by YouTuber, JOE’S RV TECH DIY:

If both sides of each fuse lights up and displays the proper voltage on the circuit tester, you know the fuses aren’t the issue.

You may be wondering why I don’t suggest using a multimeter for this process. You absolutely can if you’d like. Circuit testers are just a bit more convenient when dealing with components in an electrical system that may be in different locations.

Checking DC Output

While your circuit tester is out and connected to your battery, go ahead and test the DC output on the converter as well. Find the positive DC output wire that leads from the converter to your DC fuse block. Gently stab the tester into the output port that the wire is coming from. As with the fuses, the DC output should light the tester up and display the proper voltage. If it does not, then your converter may be malfunctioning.

This process is also shown in the above video.

Frequently Asked Questions

How do I tell if my RV converter is bad?

If the overhead lights in your RV dim over time, that’s a strong indicator that your converter might be failing. Other signs include over heating batteries, inconsistent fridge temperature, and the converter cooling system not turning on when the converter is in use.

How do I test my RV converter?

A digital multimeter and one-handed circuit tester are your go-to tools for diagnosing converter issues. These tools measure voltage, wattage, and amperage, will indicate if a component in your electrical system is failing, and help you to determine if your converter needs maintenance.


If you suspect your RV converter is bad, be quick about diagnosing the issues. A failing RV converter can damage onboard batteries, hinder the operation of electrical components, and cause an annoying speedbump in an otherwise smooth camping trip.

A well maintained RV is a happy RV. Even if your converter seems fine, don’t hesitate to do an occasional preventative inspection of your converter, onboard batteries, and electrical system. It’s better to find an issue while you’re parked in your driveway than when you’re 20 miles deep in the desert. Trust me.

Be safe and happy camping!

About Author
About Author

Schuyler has been working and playing outdoors his entire adult life. As a ski-bum in his early 20’s, he began building campers in the beds of pickup trucks to pursue a life of freedom and adventure. After a decade of experience as an artist and carpenter in Washington State, he moved to Colorado to work as an RV technician, converting vans into luxury campers. Now he is traveling the world, using writing as a way to continue his passion for creativity and artistry.

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