How To Test RV Converter And Fix It If Needed

Your converter is a vital piece of equipment in your RV, turning 120V AC power to the 12V DC power your batteries need. If it breaks down, none of the electrical equipment inside your RV will run. But how do you test an RV converter and fix it if needed?

Warning signs of a bad RV converter include flickering lights and batteries not holding their charge. Test the converter with a digital multimeter after eliminating other possible causes. You can fix simple issues such as a broken fan, but electronic problems require professional help.

It is good to test your batteries and converter when you have downtime on the road to make sure you don’t run into trouble. We will tell you how to test an RV converter to get you back to having fun and adventure from the research we have done.

Problems with an RV converter can be identified by testing, in order:

  • The AC shore power.
  • The DC batteries.
  • The converter itself.

Fixing the trouble may be as simple as replacing a fuse, or it may require professional attention for complicated electronic repairs or replacing the converter.

How To Test An RV Converter

To test your RV converter, you will need a digital multimeter. A multimeter can test all sorts of power issues and is well worth investing in. Alternatively, you can use a voltmeter; however, a multimeter can test wattage and amperage.

If you have tried the steps below to eliminate other possible causes of electrical trouble, test the AC shore power, the batteries, and the converter itself.

How To Test The AC Shore Power For An RV

Connect the RV to shore power or a running generator, and use your digital multimeter to test AC power across the 120 V terminals at the voltage box. Shore power positive is generally a black or a blue wire, whereas shore power neutral is generally a white wire.

The reading should be between 110 and 130 V. If your multimeter indicates no power is present, check the circuit breaker or fuse dedicated to the converter.

How To Test The DC Batteries In An RV

Disconnect from shore power (or the generator), and switch off the inverter, generator, and engine.

Connect your digital multimeter across the terminals of each coach battery. Coach battery positive is usually a black or red wire, whereas coach battery negative is typically white.

The batteries should be maintaining a consistent charge between 12.3 and 12.9 V. Anything less is a sign of trouble with the batteries. If no power is present, the converter is faulty.

Your batteries are most likely connected in parallel. Test them one by one to ascertain which one is faulty. Do not leave a bad battery, as it can lead to the other batteries failing.

To Distinguish RV Battery Or Converter Problems

Plug the RV into shore power (or a running generator). Use your multimeter to test a socket or light fitting. Test the batteries again.

If the battery charge terminals have a reading of approximately 14 V but do not hold a charge (as determined when testing without shore power), the fault is with the battery.

If you get a reading of approximately 14 V from the socket, but the battery charge terminals read less, the fault lies with the converter.

How To Test The Solenoid In An RV

The solenoid, or transfer relay switch, allows charging voltage to flow to the coach battery. Listen for a click when you plug into shore power. Test it with the multimeter to see whether power is flowing through it.

If no power is flowing, disconnect all power from the converter charger. Remove the converter charger case and spray the solenoid with electrical contact cleaner.

Plug the RV into shore power again, and retest the solenoid.

How To Test The Converter Itself In An RV

Test at the DC distribution panel by connecting one of the tested batteries to the DC distribution panel and connecting it to the digital multimeter. Then connect the multimeter to the DC distribution panel, and test whether it changes 120 V AC power to 12 V DC.

The input terminal of the transformer should read approximately 120 V AC (between 110 and 130 V), and the output terminal should read about 14 V DC.

If the input terminal has 120 V power, but the output terminal does not have power, the converter is faulty. If the input terminal does not have power, the fault lies upstream of the converter.

Warning Signs Of A Problem With Your RV Converter

Common warning signs of a battery or converter problem in an RV include the internal vents, cooling fan, interior lights not working correctly, or abnormal dimming or flickering of dashboard lights.

A more severe sign is if the RV’s onboard batteries fail to hold a charge properly. If this happens, it usually indicates a problem with a battery or the converter.

Basic Fixes For An RV Converter That’s Giving Trouble

If an appliance aboard your RV isn’t working correctly, don’t jump to the conclusion that the converter is giving trouble. Test that device to see whether the fault doesn’t lie with it.

Check your fuses. A fuse is a small device containing a metal resistor designed to melt if too large a current passes through. In doing so, it protects equipment downstream from the power surge. Sometimes fuses can burn out prematurely.

If you need to replace a fuse that has blown, ensure that you replace it with one of the same rating (they are color-coded). RVs mostly use 10, 15, and 40 A fuses, which are easy to obtain and cheap.

If you don’t have a fuse of the same rating, use a fuse with a lower rating (it will simply burn out before it’s supposed to). Never use a fuse with a higher rating than the one you are replacing, as you risk severe damage to your electrical equipment from power surges.

We recommend investing in a pack of fuses, with multiple fuses of each rating that you will require for your RV. You will be prepared for when a fuse blows.

Also, check the breakers to see whether the breaker for the converter has tripped. If it has, unplug the converter and reset the breaker.

The problem may lie with a converter fan that is not working correctly. Make sure that the ventilation around the fan isn’t blocked. If the fan is faulty, you can replace it. Do it as soon as possible, because excess heat will damage the electronics of the converter.

Disassemble the converter to check the circuit board as a last resort. If the fault lies with the resistor, resistor gates, or diodes, you will have to have a professional fix it for you. A common sign of trouble is whitish acid residue around components.

If the entire converter needs replacing, get an RV technician to do the job for you.

Good luck, and happy camping!

Check out our article on: RV Water Pump Keeps Running (How To Troubleshoot And Fix)

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