How To Protect Your RV From Low Voltage

TheRVgeeks Electrical, Great RV Products 70 Comments


Hughes Autoformers is now offering RVgeeks viewers a 10% discount when you order either a 30-amp (Model #RV2130-SP) or 50-amp (Model #RV220-50-SP) direct from them at Use the Coupon Code “RVGEEKS” at checkout!
NOTE: this discount does not apply to any other Hughes products

Over eleven years of full-time RVing, we can’t begin to count the number of times we’ve hooked up at RV parks and seen readings on our voltmeter that are way too low. Low voltage can cause valuable electronic equipment to draw more amps, or current, which can lead to overheating and premature failure.

The solution to low voltage is an autoformer. We use the name that’s synonymous with autoformers: Hughes.

So we’re excited to announce our newest RVgeeks Contest! On Monday, May 5, 2014 at 8pm Pacific Time, two lucky RVgeeks viewers will each win a Hughes Autoformer! We’ll be giving away one 50-amp unit and one 30-amp unit, with a total retail value of over $900!

The contest ends on Monday, May 5, 2014 at 8 pm Pacific time, so watch the video for details and be sure to enter today!


( Don’t forget to subscribe to our blog to be notified of  upcoming giveaways! )

While low voltage isn’t desirable for any equipment, the things most vulnerable to damage are devices with motors in them, like clothes washers & dryers, residential refrigerators and expensive equipment that just about every RV uses, such as microwave ovens and especially air conditioners.

Visit Hughes for more information & Use coupon code “RVGEEKS” at checkout to save 10% on the purchase of a 30-amp (Model #RV2130-SP) or 50-amp (Model #RV220-50-SP) autoformer!

Be sure to enter the contest, and good luck!


Congratulations to our winners!

Scott T. (Entry #13) won a 50-Amp Hughes Autoformer
for his 2008 Grand Junction 5th Wheel.

Doug H. (Entry #684) won a 30-Amp Hughes Autoformer
for his 2007 Fleetwood Pioneer Travel Trailer.

Scott & Doug have already been contacted
and their prizes are on the way to them!

Thanks to everyone who entered.  Stay tuned
for the next RVgeeks contest, coming soon.

We're handy RVers, not professional technicians. We're happy with the techniques and products we use, but be sure to confirm that all methods and materials you use are compatible with your equipment and abilities. Regardless of what we recommend, consult a professional if you're unsure about working on your RV. Any task you perform or product you purchase based on any information we provide is strictly at your own risk.

We sometimes receive products for evaluation at no cost, and The RVgeeks are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites. But our opinions are our own, you won’t pay an extra penny, and we only link to products we personally use, love and can recommend to friends with complete confidence.

Comments 70

  1. I like the concept and design of the Hughes Autoformer RV220-50SP — portable protection and correction for power surges and brown outs. But I have a question: other than power correction, what advantages would a Hughes product have over a solution like a Progressive Industries EMSHW50C Surge Protector?

    As I understand it, like the Hughes Autoformer, the EMSHW50C (which can be built in) will protect against surges and brown outs by isolating your coach from the shore power source. The Progressive solution will not, however, adjust/correct inbound voltage like the Hughes. Another obvious difference is the price. The Hughes Autoformer is significantly more expensive than the Progressive solution.

    Online reviews of both products are very positive. So is this just a choice between getting more or less functionality based upon perceived needs? BTW: we are not full-timers, but we do spend a few months every year enjoying the open road.

    1. Post

      Hi Thomas! We’re not 100% up-to-date on all the features of the Progressive unit, but one of the features that the Hughes Autoformer has (in addition to also providing the power boosting, which the Progressive unit doesn’t do) is that the surge protection (which has a higher Joule rating at 4,800J vs Progressive’s 3,850J) is a user-replaceable unit. So if the Hughes protects you from a surge, you can order and replace the part of the unit that sacrificed itself to save your other devices. The Progressive unit reports that it is “field serviceable”… but we don’t know if that means you, the end user… or a certified repair location.

      Now… to be fair… in 15 years of full-time RVing, we have never had our surge protection trip (knock on wood). But we HAVE had LOTS of parks with low voltage situations, where running equipment like Air Conditioners and other high amp-draw devices benefit from the voltage boosting of the Hughes.

      Hope that helps!

      1. Not surprisingly, your posts on various RV topics have helped me to apply DIY solutions to a number projects (e.g. slide topper awning removal/repair). In addition, I put a lot of stock in your opinions regarding RV systems and technologies (e.g. the VIAIR-400P-RV, which we purchased).

        Your response to my question regarding popular power protection systems certainly helps our decision making regarding an upgrade: we’re going with the Hughes – definitely worth it.

        Thanks again!

  2. I just wanted to thank you guys for turning me onto Hughes Autoformers. We just started staying at a permanent campground. The first warm weekend our Progressive Ind. EMS shut off the power due to low voltage. We had never had this happen in 5 years of camping but I knew low voltage was bad for the A/C unit. Got the Autoformer and no more worries. Thanks again!!

    PS – Love your videos. VERY informative. Keep up the great work.

    1. Post

      Hi Les! Thank you so much for taking the time to share your experience, and let us know we’ve been helpful. Hearing things like this makes everything we do feel worthwhile, and we can’t thank you enough for making our day. So glad you love your autoformer as much as we do. ?

  3. I’m so glad I found this information! We purchased the 50 amp autoformer based on your video and I feel so much safer by doing so. Thanks! Love your videos, which I only discovered after watching you crew with the Wynns in Panama.

    1. Post
  4. Thinking of buying our first RV to live in full time. Love your videos, helps to really understand the maintenance needed.

    Question… will this Hughes protector (that you have installed of the shore power) protect your power from the batteries and/or the generator? Do you need any protection from a generator and/or batteries?

    Thanks again for all the fun stuff on here!

    1. Post

      Hi Joe! The Hughes protects the shore power and we’ve never had, nor been aware of the need for, protection from generator or battery power. Thanks for the nice comment and great question. ?

  5. Gentlemen,

    I have a few questions, and comments; the cheapest item I’ve found on your site is boiling eggs, I do that regularly now, in fact, this morning, I’ve bought almost everything else.

    I have a 2016 Tiffin Red, three years later, since your low voltage video, is the Hughes 50 amp low voltage booster still recommended, and a 50 amp extension cord?

    I am considering dumping my bulky ladder for a seven foot folding ladder, but I haven’t seen you on it on any of your videos, do you like your folding ladder?

    Lastley, do you have any comment about 303 vs Protect All?

    You guys have the best videos and comments, hands down, really enjoy your site.

    Be safe,


    1. Post

      Hi Todd!

      Thanks very much for your kind comments.

      First off, we’re sorry we’ve cost you so much money. We do hear that quite a lot. LOL If you want to find something even cheaper than eggs, we do have a little video about celery, which is probably even less. ;-)

      We do indeed still love our autoformer, and use it just about everywhere, along with a 50-amp extension cord. If we had it to do over again, we’d skip the separate surge guard (which we hard-wired in long before we’d ever heard of Hughes) and simply hard-wire in a Hughes unit, which already includes surge protection. Hard-wiring it in would eliminate the need for a 50-amp extension cord for us.

      We’ve had the same compact collapsible ladder for most of the time we’ve been on the road. It folds up into a long, thin, easily-stowable shape, and we really like it. It’s in our favorite gear listing here.

      Protect-All and 303 are supposedly very similar products, but we’ve only used 303, which we love, so no experience with Protect-All.

      Hope this helps a bit!

  6. Hey guys I have to stop coming to your site as you are costing me way too much money :-) Just ordered one of these and the PressurePro TPMS and the Wifi Ranger and the Viair and the Roadmaster 576 and a Honda CRV (just kidding on the CRV). None of which are cheap items. I think I am set now I hope! Thanks for everything you guys put out there, I will feel much safer and prepared in this new journey.

    1. Post
  7. I’ve read where if one has a 30 amp system, buy a 50 amp surge protector. It will work on a 30 amp system and if one moves to a 50 amp no upgrade necessary. Could the same be said about a Hughes auto former? Or should one stay with 30 amp to 30 amp.

    1. Post

      Hi Joel! The ONLY reason we can think of to spend the extra money to buy a 50-amp autoformer for a 30-amp RV is is you specifically plan to buy a 50-amp RV to replace your current one. It’s not needed on the 30-amp rig, and will require you to use a dog-bone adapter from the RV to connect to the autoformer (30-amp female to 50-amp male), and a second dog-bone (50-amp female to 30-amp male) to plug into a 30-amp pedestal. It can certainly be done that way without harming anything, but the added cost and weight of the 50-amp autoformer, and the extra dog-bone (you would have no reason to own a 50-amp female to 30-amp male with a 30-amp RV), would lead us to recommend going with the 30-amp unit unless you have a pretty good idea that you’ll want to upgrade to a bigger RV within a reasonable period of time.

  8. Hi,
    My wife and I will begin full-time RVing this summer and we have enjoyed viewing your videos and learning from your experience. We are planning on purchasing a Hughes Autoformer and placing it inside the RV as you do. My question is: How long of a 50amp extension cord would you recommend? We will be completely knew to this so don’t have much of an idea on what is typically needed. Thanks so much.

    1. Post

      Hi Larry & Karen! It’s so good to hear that we’ve been helpful. Thanks for the nice comment. The Hughes unit is so great, and even though the way we’ve chosen to keep it (inside) prevents us from easily using our electric cord reel, it’s worth the effort to use a 50-amp extension cord instead. This 30-footer is one we recommend will do the job for you in most circumstances: 50-amp cords are so heavy that anything longer than that would be fairly cumbersome, and 30 feet is more than enough for the vast majority of situations. In a pinch, if we’re just too far away from the pedestal, we very occasionally reel out some of the built-in cord to add that length to the extension cord. That of course means that the Autoformer is now either not used, or would have to be outside. In those cases, we opt for the former, not wanting to leave our autoformer outside. In that rare situation where the pedestal is that far away, we have one other option, which we’ve used a couple of times. That is to break out our 50-foot 30-amp extension cord (we keep one of these on board as well: ) and just dog-bone down to 30 amps with a 30M-to-50F adapter ( ). That works great in places where we don’t need too much power (basically as long as the A/C isn’t needed). In those cases, 30 amps is plenty.

      One other option, if you’re comfortable cutting your power cord and installing it, is a hard-wire kit from Hughes. We’ve never bothered doing that because our electrical compartment is pretty tight, and we already cut the cord to install a surge protector years ago (which we don’t actually need any more because the Hughes unit provides surge protection too). Hope this all helps, and hope you have a blast going full-time. We’re excited for you both!

  9. I was just at a State Park over the weekend. The park only had 30 AMP service. When nothing was running the power read Line 1 = 118 Line 2 = 121. When one of the heat pumps clicked on the volts dropped to Line 1 = 103 Line 2 = 103. My question is would an auto former of helped us here or was there some other issue going on here that would cause the voltage to drop so much when only one heat pump was running?

    Thanks and Great Videos and Web Site.

    BTW I have a 2014 Itasca Meridian 40U.

    1. Post

      Hi Tom. Not sure about the discrepancy in the lines, but it’s possibly due to normal variation. The extremely low voltage that you experienced when you turned on your heat pump is precisely the problem that an autoformer is designed to solve. When you’re in a park with such weak power that a single heat pump pulls it down that much, an autoformer will basically swap out amps for volts, providing you with enough voltage to avoid damaging your equipment. Your RV has 50-amp service, so you’d need the same unit we have… the one we showed in the video… but they’ve updated it with a new & improved model: Hughes offers our viewers a 10% discount… just use the discount code RVGEEKS to save 10% at checkout. They’re still a bit pricey… but so are replacement air conditioners. ;-) Our RV is 10 years old and we’ve never had a day of trouble with either heat pump / air conditioner, or any other electronics for that matter.

  10. I’m a newbie to this RVing so maybe this a dumb question, do I need two Autoformers 30amp & 50amp? I have a Diesel Pusher I just got and it’s 50amp but I’m told that not all parks are 50amp only 30amp.
    That said since I plan on going across the U.S. and staying at all kinds of parks, would it be wise to have both?

    1. Hi Jeff! Not a dumb question at all. You only need a 50-amp autoformer, which you can plug your RV into, and then plug it into 30-amp pedestals using a dogbone, the same as if you weren’t using an autorformer at all. In case you need more info about dogbones, here’s a video we made with everything you need to know: Hope this helps!

  11. magnificent post, very informative. I ponder why the opposite
    experts of this sector do not notice this. You must proceed your writing.
    I’m confident, you’ve a great readers’ base already!

  12. I got a Hughes Autoformer (haven’t used it yet), but I was wondering if you also use a surge protector in your setup? If not, why not?



    1. Hi Mark. Long before we had ever heard of autoformers, we purchased and permanently installed a surge protector, so we now have both as a result. If we knew then what we know now, we simply would have purchased the autoformer, since it includes search protection.

    2. Hi Mark. Long before we had ever heard of autoformers, we purchased and permanently installed a surge protector, so we now have both as a result. If we knew then what we know now, we simply would have purchased the autoformer, since it includes search protection.

  13. Just found the web site and boosted my wifi signal so I can get them uninterrupted !!! All RV’ers need these! We are full-timers for almost two years and I wish I had these when we started.

  14. Wow just started looking at your videos. You do a fantastic job. Very informative. I think I will be contacting M4 very soon
    One question with the puck lights that where using the old JC10 bulb how did the LEDs workout in the puck. Do you have the LEDs blow out often like the old bulbs would? Seams I am always feeding my trailer JC10 bulbs every time I take it out somewhere. Just wondering if the LEDs last in the puck lights.
    thanks and keep up the good work

    1. Hi Anthony! Thanks for the nice comment and welcome to our video blog. We haven’t had the LEDs very long yet, but we’ve never had a problem with our halogens burning out (or the new LEDs of course). Is it possible that the voltage in your RV is fluctuating and/or spiking? There are a couple of possible problems. First, if you have an old battery charger, it might be failing or possibly set incorrectly, putting out excessive voltage. Or you might have one or more old batteries which are failing, causing the charger to keep the voltage higher than usual to compensate. That higher voltage might be causing the bulbs to burn out. The LEDs at M4 have good capacitors designed to make them resistant to voltage fluctuations (check the specs on M4’s website for the bulbs you have in mind to be sure they list 10-30 volt range). If you’re getting very high voltage readings, it might be a good idea to find the source of the high voltage first and fix it before possibly damaging nice new LEDs. ;-)

  15. I’m a newbie at all this! Starting right off in the RV world with no prior experience. I will be going FT on June 15th! I could really use the 30amp autoformer! I really like your videos! SOOOOO informative! Thank you!!

  16. Hi,
    about a year and a half ago I discovered your videos and have enjoyed them very much. The best thing I liked right from the start is I have the same motorhome as you. I have gone through all your videos from adjusting the hold tank levels, I changed out three of my slide toppers using your recommended supplier, changed my water filters and many of your other things you pointed out in your videos. I was delighted when you recommended M4 for LED lamps. I have retrofitted my entire Mountain Aire using M 4 about 8 months ago. Steve was a big help to me also. I have also installed a water softener which will help preserve my Hydro Hot water system. Another addition I have installed is a Samsung all electric refrigerator that runs on 5 amps or less. My next project will be installing a 600 watt solar system. I want to thank you for giving me you knowledge and tips in all your videos. I really enjoy and look forward to more of your videos.
    Thank You
    Robert Van Setten

    1. Thanks fore making our day Robert! And we hope you love your Mountain Aire as much as we do. And we sure do agree with you about Steve at M4. He is the best. :)

  17. I, like many, have never heard of this before. But, it makes loads of sense. I am a police officer that is on the threshold of retiring and going the full tilt on Rving with a 5th wheel. Thanks so much for all of your VERY instructional videos. I have amassed a full book of notes just from them. Keep it going guys!

    1. Thank you so much for your kind comments Keith! It’s always great to hear that we’ve been of help. Happy to hear you’ll soon be full-timing too. It’s a wonderful way to live.

  18. I am a senior grandmother and solo travel. I do not know how to use a multi meter. I have a volt plug in monitor that I have plugged in. It is my understanding I should use the multi meter at the post before I plug in. I’ve seen them from $10-$50 don’t know what I should get or how to use it. Any suggestions and or referrals where I can find out about this would be appreciated.

    Tks, Dy

    1. Hi Dy! It’s so great to hear that you’re out there traveling as a solo senior. Good for you! We’ve also heard that in an ideal world, you should test the power at the pedestal before plugging in. We’ve never done that, because we always used to use a surge guard and we now use the autoformer. Both automatically check for correct pedestal wiring, so we don’t bother using a multi-meter too.

    2. Hi, Dy: I, too, am a senior solo — not full time but way past part-time. This Autoformer sounds perfect in that apparently you don’t have to monitor current constantly; it does it for you. How cool is that? I didn’t know about it before.

      You probably have the plug-in voltmeter that I have for monitoring, which is very helpful. Another brand that you may want to look into to plug in in the interior is Kill-A-Watt. It can give volts, amps, and other stuff. I don’t pretend to understand it all, but at least I know when there’s something amiss. You’d be surprised about how many volts your coffee maker draws.

      Anyway, Amazon now carries a nice selection of electronic surge protectors for monitoring purposes — that’s the category I’d start with, “surge protectors” — and online places like Tweety’s, Camping World, and PPL.. I have a cheap surge protector that alerts me to miswiring and other things that go awry at the pedestal, but the proof is what the plug-in voltmeter says. I’ve recently left an RV park that only was reading 110 volts consistently.

      With this Autoformer, you can enjoy your site stay without the constant sense of needing to make sure your current is in the safe range. It monitors it for you. What a great invention!!!

      Don’t pay any attention to those who call you a fussbudget or worse. It’s your rig. Protect it.

  19. Can you explain how the autoformer hooks up when you put it inside the electrical compartment? Is special wiring required or am I making this more complicated than need be? :) Thanks for the informative vids.

    1. The way we have keep our autoformer (as shown inside our electrical compartment in the video) is simply with it sitting inside the RV with our 25′ 50-amp extension cord plugged into it, then feeding the cord out through the access port at the base of the compartment door and over to the park’s power pedestal. The RVs power cord stays reeled up on its reel, since it only has to reach the outlet on the autoformer, which is sitting right there. If we were to use the Hughes installation kit, that involves cutting our main power cord and mounting the autoformer in line with it, so that it could remain in the power bay. Hope that explains everything!

  20. Very good info there and all ways a great eye opener thanks great Job
    see ya in the Camp ground


  21. Thank you for your informative videos. As a new 5th wheel owner (10 months)we have gleaned very useful information. We are heading out this weekend camping and will definitely be taking a voltage meter. Thank you for the opportunity to enter your contest.

      1. Unfortunately we were blown out for the weekend and I forgot the multi-meter. Headed to Lone Pine California but cut short at Inyokern due to wind. 5 tractor trailers were blown over so went back home. Headed to Texas in a month so will make sure to check voltages along the way.

  22. Hello and thanks for the great information you always share!

    I am wondering if I should return the $225 surge protector and get an auto former instead? (For $100 more)

    Do I need both?

    Thanks for clearing this up for a newbie! I love your emails as I learn so much, but this auto former vs. Surge protector has me a little confused.

    1. Besides boosting voltage, the autoformer also provides surge and spike protection, so you don’t need to own both. Of course a unit that only provides surge & spike protection won’t do anything to fix low voltage.

    1. I also didnt know there was such a thing and here I was trying to figure out one myself and thinking about it till it hurt LOL Thanks again Geeks

      p.s. mine would not have auto boosted like this one does thats not in my range of knowledge

  23. Great Video!

    Have you ever had to leave a campground due to low voltage? If so, at what level would cause you to leave?


    1. That’s a great question Mark. We can’t recall ever actually leaving a park, but we sure can recall many times (before we had an autoformer) that we had to forego running either air conditioner or using the microwave, and had to use propane to heat water instead of electric. If we were in a really beautiful spot for only a short time, and no other camping options were available nearby, we’ve managed to live with that. If we were planning to be there for a long time, we’d almost certainly move elsewhere, especially if it was very hot and A/C was a must.

      We always used to worry about damaging things, especially our A/C units, when voltage drops too low (anywhere south of 110 starts to make us feel uncomfortable putting our expensive equipment at risk… but that’s just us). With our Hughes unit, we don’t have to worry about it. The only problem would be parks with power below about the mid-90s or so, because that’s so low that even an autoformer can’t make up the difference. We’ve seen power that bad only rarely, but at this point I’d say that would be cause to move, since we’d be paying for power that we basically couldn’t use.

  24. As a long time RV’er I have to say I am a bit embarrassed that I don’t know how to use a volt meter except for the most basic of functions. I do use a voltage regulator that shuts power off to the coach if power drops out of range. How about a quick tutorial video on basic uses for voltage meters for the RV’er? Love the site!!

    1. We actually don’t use our voltmeter for anything else, Jeff. But we do use our multimeter for all kinds of stuff, so we’ll have to look for opportunities to show it in action! :)

  25. Another great video thanks! Full timing for 3 years I can recall a few parks that specifically have rules against using autoformers, not sure why? I like the way you have your power cable, specifically where it enters the coach. I see there is no hatch to pull the cable through. Did your coach come that way?

    Thanks, Ray

    1. Some people (including some park owners apparently) think that the way autoformers work is to “steal” power from other sites. That is absolutely untrue. They simply swap amps for volts. Our RV electrical compartment came with that great little pass-through at the bottom to allow you to close the door with the cord out. Our water hose extends through a similar opening.

  26. Hey guys thanks for tips regarding the Hughes. I have used one
    For years and what a great investment to protect all our
    Rv appliances.

  27. I never though about if the peds are getting the proper voltage until now. We are going camping this weekend and will definitely bring my meter with me. This was another outstanding video on protecting your RV. Thank you again and thank you for taking your time to share your experiences.

  28. I would like to enter the contest, but can’t bring myself to allow access to my friends list. I can think of only one reason why the contest administrator wants that information; to send advertisements to them. I’m not willing to subject my friends to un-requested advertisements.

    1. Hi Lowell. Sorry I’m not following you. Are you referring to being able to log in and enter via Facebook? If that’s a concern, please feel free to enter using your e-mail address instead. Thanks! Peter

    1. We know RVers who don’t even own a voltmeter, because when we’ve asked about the voltage in a particular park, they have no idea and seem to wonder why we even care. lol I think that if the power is on at all, they just figure “power is power.” NOT! ;-)

  29. I love theses articles for my camper. I am way ahead of my friends with what I learn from these articles.

We'd Love To Hear From You... Leave A Comment!

This site uses Akismet to reduce spam. Learn how your comment data is processed.