Everything You Need To Know About RV Autoformers + Reviews

What Is An RV Autoformer?

It’s very common for people to confuse autoformers with surge protectors, and while they both can measure the voltage going into an RV they do very different things. Some autoformers like the ones I’m going to be reviewing today are a combination of a surge protector and an autoformer.

Every RVer should have a surge protector and if you travel to different RV parks and campgrounds often it can be a good idea to get both a surge protector and autoformer whether it’s a combination of both or two separate things.

Related: Save 50% On Campgrounds All Over The United States With Passport America  

Now to the question, what is an RV autoformer? An autoformer is the combination of the two words “automatic” and “transformer.” But an RV autoformer is different from an autotransformer. Confused yet?

RV autoformers are used to increase the voltage going into your RV whenever it senses that it is too low. although it’s called an autoformer it’s actually a step-up transformer or a voltage booster. This differentiation is important because autotransformers are illegal to use on RV’s according to the National Electrical Code. Don’t let the language fool you, RV autoformers like Hughes Autoformers voltage boosters are legal to use with your RV because they are not autotransformers, they are RV voltage boosters.

See Also: RV Life Hack: 6 Things You Can Do To Fix A Broken RV Outlet

Why Should I Get An Autoformer For My RV?

The main reason you should get an autoformer for your RV is to protect the appliances in your RV. All electrical appliances are sensitive to low voltage, especially ones with motors and compressors like air conditioners, refrigerators, and microwaves. Smaller electronics like computers are also sensitive to low voltage and can be damaged over time.

The low voltage causes electrical appliances like these to draw more current to keep running. Overheating occurs and the electrical components start to get damaged. An easy to see example are the charging cables to computers. They get really hot when plugged into outlets with low voltage and will wear out faster than when they are plugged into outlets with the proper voltage.

See Also: The Surprising Differences Between 50A & 30A RVs

Lots of RV parks and campgrounds have problems with low voltage. Whether it’s from old age or high power demands you want to be able to protect your RV and the expensive appliances inside. Getting an autoformer will help keep the voltage in the safe range so everything can keep running safely without the risk of being damaged and overheating.

The Best RV Autoformer: Info & Review

Hughes Autoformers 50A RV Voltage Booster

Hughes Autoformers RV220-50SP Voltage Booster (with Surge Protection), 1 Pack

Check Price at Amazon

When it comes to RV autoformers that boost voltage and have surge protection Hughes Autoformers Voltage Boosters are the best of the best and the most popular step-up transformers for RVs on the market today. I’m going to review the 50 amp version but there is also a Hughes 30 amp Voltage Booster (click to view on Amazon) that has all the same features.

First off let’s talk about the step-up transformer part of this neat RV gadget. It’s 50 amp and has 12,000 watt capacity just like a 50 amp RV, 5th-wheel, or travel trailer. The total voltage boost can go as high as 10%. If you need more than 10% voltage boost to stay within safe voltage parameters (114-126 volt) then do not plug in your RV because there is something seriously wrong with the electrical system of the RV park or campground you are staying at.

See Also: RV Life Hack: Equalize RV Batteries That Can’t Hold A Charge

There is also a diagnostic feature on the Hughes Autoformers Voltage Booster. When you plug it into the power pedestal it will test the power going to both hot legs (only 1 hot leg on the 30 amp), as well as the ground and neutral connection. After testing, the light indicators will show green if the power is safe to plug into or not.

Hughes Autoformers RV220-50SP Voltage Booster (with Surge Protection), 1 Pack

You will also be shown when the autoformer is boosting voltage or in the non-boosting mode which will only be boosting the voltage at a low 2%.

Not only does the Hughes Autoformer boost voltage it’s one of the best surge protectors on the market today. That’s why I recommend the voltage booster to people who were going to buy a surge protector anyways. It has up to 4,800 joules of protection on the 50 amp version and 2,400 joules for the 30 amp version, which is standard for all high-quality surge protectors.

There are indicator lights that will shine green when the surge protection is functioning and red lights that will show if the surge protection unit is damaged. Unlike a lot of other lower quality surge protectors, the unit is replaceable. So you don’t have to worry about needing to buy a new RV autoformer if the surge protection ever needs to be replaced.

The Huges Autoformers RV Voltage Booster is not waterproof or weather-resistant so you will need to keep it covered when it rains. The box is fairly small in size and you can put it on a block of wood and place a bucket over it to keep it dry. Or you can do what a lot of RVers do and mount it inside your RV. This will protect it from the weather, theft, and prying eyes.

Because so many people like to install their RV autoformer/surge protectors inside their RV they sell easy to use installation kits for both 50 amp (click to view on Amazon) and 30 amp (click to view on Amazon).

Install Kit - 50 Amp

The Hughes Autoformers 50A RV Voltage Booster and its 30 amp version are high-quality, dependable products that will protect your RV. Whether it’s low voltage or high power surges Hughes Autoformers have you covered.

Every RVer should have a surge protector no matter how often they hook up to electricity. A dangerous surge only needs to happen once to fry the electrical system and appliances. Low voltage the other killer of electrical appliances and you may as well have that protection as well. If you RV in hot places during the summertime and need to run one or even two AC units an RV step-up transformer like Hughs Autoformer’s is a must-have.

See Also: Best 13,500 & 15,000 BTU RV Air Conditioners


  • High-Quality Surge Protection
  • Pedestal Diagnostics
  • 10% Voltage Boost
  • Can Be Mounted Inside RV
  • Compatible With Adaptors

Frequently Asked Questions About RV Autoformers

How do I use an adaptor with an RV autoformer?

You can use adaptors to plug 50 amp RV autoformers to 30 amp power or vice versa. Just make sure you plug the adapter into the power outlet first, then plug in the RV autoformer, and then the RV.

See Also: Will A 50A Surge Protector Work In A 30A Outlet?

Are RV autoformers illegal?

An RV autoformer is technically a step-up transformer that is made to boost the voltage. These are legal. What’s illegal is an autotransformer. Some people confuse Hughes Autoformers RV voltage boosters with autotransformers because of the name Hughes Autoformers. Their voltage booster is not an autotransformer, it’s a booster, and it’s legal to use with an RV.

That being said some RV parks do not allow voltage boosters. Be very careful when staying at these kinds of places. They don’t want people using RV autoformers because they have a weak and possibly unsafe electrical system.

What is the right sequence to use an RV autoformer with a surge protector?

When using an individual RV autoformer with a surge protector you plug the autoformer into the pedestal first followed by the surge protector and then the RV. If you plug the surge protector in first the low voltage from the pedestal will cause it to keep shutting off.

Because you plug the surge protector in after the RV autoformer hard-wired surge protectors can be used with RV autoformers.

What do I do if my RV autoformer is boosting voltage too high?

If your RV autoformer is malfunctioning and boosting the voltage so much that the autoformer switches off (usually around 130 volts) you may have some loose wiring in your electrical connections. Turn off all the power to these cables and plugs and check each one to make sure your wires are tight.

If this doesn’t solve the problem your RV autoformer may require servicing. Most companies recommend sending the autoformers back to them to be fixed by their own knowledgeable professionals. n

Will an RV autoformer decrease the voltage for other RVs in the campground or RV park?

If the voltage in an RV park or campground is low then using an RV autoformer will boost the voltage for your RV but it will slightly decrease the voltage for the other RVers that are plugged into the same system as your RV. That’s a big reason why substandard RV parks and campgrounds don’t like RV autoformers. If everyone is using an autoformer it could blow their already stressed system.

There’s a lot of debate on if using an autoformer is ok or not in crowded RV parks and campgrounds. On the one hand, it isn’t ok or sometimes even legal for businesses like these to be suppling low voltage as it is a safety issue. Using an RV autoformer is only protecting your RV and the expensive equipment inside.

On the other hand, using an RV autoformer in a campground or park where there is very low voltage from heavy electrical demands will only make the problem worse for other RVs. It may even be what pushes the voltage so low that it damages the sensitive electronics in other RVs that don’t have an RV autoformer.

My suggestion would be to look at each situation and go from there. If you can avoid RV parks that have very low voltage that’s below 114 volts you should. If there are only a few RV’s plugged into the same system, then your RV autoformer shouldn’t make that much of a difference. If the voltage is sitting right at the 114-volt line and there are lots of RVs plugged into the same system using your autoformer may not be a good idea.

In the end, the decision is up to you and sometimes the RV park. Make sure you check with the rules of any place you stay, they may not allow RV autoformers.

How do I quickly test the voltage in an RV outlet?

To make sure your RV autoformer is working properly or to test the voltage in the outlet to your RV at any time you can use a few different devices like multimeters and voltage testers. A simple, easy to use, and quick gadget you can use is an outlet ac 120 volt meter like the . All you have to do is plug it into an outlet in your RV and it will tell you what the current-voltage is. It the dial is in the green the voltage is acceptable.

Don’t leave this meter plugged in all the time. Only use it when you want to test the voltage in an outlet.

Should I use a surge protector if I use an RV autoformer?

Yes, you don’t technically have to use a surge protector if you use an RV autoformer but you should always use a surge protector anyways. Even if you don’t use an RV autoformer a surge protector should be used to protect your RV from power surges caused by things like lightning and faulty wiring.

Can you use an RV autoformer with a generator?

This is a difficult question to answer. An RV autoformer should work with a generator because the generator shouldn’t be putting out low-voltage. If you have a hardwired RV autoformer then you may need to do this. If you have the option to not plug your autoformer into a generator then you should just not plug it into the generator instead.

If the RV autoformer is an autoformer and surge protector combo your generator might not work with the surge protector. For information on how to get a generator to work with a surge protector check out this article here.

See Also: The Best Camping Gas Generators That Will Run Your RV AC

Have any more questions about RV autoformers (voltage boosters)? Leave a comment below.

Jenni grew up in a small town in Idaho. With a family that loves camping, she has been towing trailers since a very young age.

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