By Mike Sokol
Dear Readers,
Not a week goes by without me receiving at least a few emails and questions about the Hughes Autoformer. This is advertised as a cure for low campground voltage, and its users are adamant about how great it works, and everyone else at the campground is shutting down while their own air conditioner is still working, etc.
Note that in the 2020 National Electrical Code any voltage boosting transformers have been made a violation of NFPA 1192, allowing campgrounds to force you to disconnect or leave. This is based on the premise that an Autoformer (or autotransformer) increases the amperage draw of your RV’s electrical system to make up for the lower voltage.
There’s nothing magical about the Hughes Autoformer since it’s basically an autotransformer with a voltage sensor and transfer relay. When the incoming voltage goes below a certain value, the relay kicks in adding a 10% voltage boost. I’ve been installing autotransformers (the manual version of this product is called a buck/boost transformer) in industrial buildings and churches for more than 40 years, and I know exactly how they work.
According to the NEC, these autotransformers increase the amperage load in a campground electrical grid because they draw 10% more amperage than the RV should be using. But according to Hughes, they actually help reduce overall amperage draw because air conditioner and refrigerator compressor motors tend to draw more current as the campground voltage gets lower.
According to me, I know that both of these statements are true to some extent, but I don’t know which one has the greater effect on campground power. Do RV air conditioners really draw more amperage as the voltage goes down? All my textbooks say so. Does the Hughes Autoformer have the ability to negate that extra amperage draw enough to make up for the extra amperage it uses to boost the voltage? Heck if I know for sure. I can run textbook calculations all day long, but it’s hard to know all the variables.
However, I do know one way to find out. I’ve just bought a 3kVa variable transformer (a VariAC) that can vary the line voltage from 0 to 140 volts. And my HRDL (High Speed Data Logger) meter can monitor both voltage and current going in and out of my VariAC with extreme accuracy. And while I’m at it, I’ll also do this experiment with both a SoftStartRV controller and the factory starting capacitor on a Dometic Penguin II 15KBTU air conditioner.
Finally, if Hughes will send me a 30-amp Autoformer to try out, I’ll be glad to put that in the circuit as well and share all my test data with them as well as you. Be be aware, this will be a warts-and-all review, so whether it works as Hughes says it does or not, I’m publishing either way. That’s my guiding principle.
Sadly, I have no budget for any of this so I’ll have to spend dozens of hours and hundreds of dollars to do this experiment. But I think it’s worth it in the long run to answer the Hughes Autoformer question for the RV industry once and for all.
Stay tuned for a real scientific study on this technology. See you then.
Let’s play safe out there….
Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.
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Mike, going back to a statement in the article “Note that in the 2020 National Electrical Code any voltage boosting transformers have been made a violation of NFPA 1192″… Is the updated code a broad statement or more refined… asking because aren’t all those large transformers all around the campground (installed by the power company) doing the same thing to regulate the campground power from the power company?
Al, well those transformers installed by the power company are something completely different. Their job is to step down the 11,000 to 17,000 volts coming from the power company substation, to split-phase 240/120-volt (and sometimes 3-phase 208/120-volt) power so you can plug your RV directly into a pedestal outlet. The Hughes Autoformer is an automated switching buck/boost transformer which boosts the voltage by 10% when it drops below a certain value.
Thanks Mike, that is what I thought… just wanted experts confirmation.
I remember from my quite abbreviated career as a EE college student (I mean REALLY abbreviated) that electrical power is measured by multiplying voltage times amperage. Since a transformer only changes voltage, then power in equals power out (less any inefficiencies in the device). How a bunch of smart electrical guys didn’t know that implies someone might have had an ax to grind.
Sure it will promote more power consumption. When the voltage drops low enough, those of us with power protection will disconnect and sit there hot and dark. If we condition the electricity we’re paying for, we’ll use it.
Shame on Hughes if they made unrealistic claims. I guess you reap what you sow.
Michael, it’s a little more complicated than that. The voltage time amperage equation only works for resistive loads, not inductive AC loads with a spinning motor which behaves in a non-linear fashion due to reduced back EMF at lower source voltage. Add in PWM power supplies and electric water heater elements and you have a wild mixture of reactive loads, some of which are auto compensating. I agree that the Hughes marketing literature seems to be misleading, but I’ll soon know if any of their claims are false or not. Stay tuned for science….
Just as an aside to this- I quit using the 30a. receptacle at the campground pedestal years ago. I use a 50 to 30a dog bone to use 1 leg of the 50 for my power. The design is superior to the 30a. and it should handle higher amperage better. In addition- one leg of the 50 is 50 amps, where the only hot of the 30 is just 30 (in a park where the 30a. receptacle is new or nearly new.)
Drew, I’ve actually ran into RV Parks that prohibit dog-bones on any kind… 30-to-50 or 50-to-30. Their real reason to ban both is because of the 30-to-50 that they claim you will be trying to pull 50amps out of a 30amp circuit and damaging their pedestal!
I know everyone thinks this is a game of hide and seek, but it’s a real issue that needs science to prove one way or another. That’s why I’m going to spend 40 hours or so this month testing both sides of the theory. Does the Hughes Autoformer actually steal power from other campsite pedestals (as the NEC alleges) or does it save campground power by allowing the air conditioners to run more efficiently at their design voltage? That’s the subject of my test. Please stand by….
“But fact is, many of them are in serious trouble trying to supply power through an antiquated power grid.”
Mike this is your comment and I agree 100%. I the last two weeks my local energy coop has limited ( thru electronic monitoring installed) my AC usage when it is really hot. The AC is turned off and back on automatically according to overall grid usage and health. Campgrounds I am sure are in the same boat.
So Mike, Reading you column and thanks it is great, Interested in the hard start cap test.
But with the Autoformer I have a question. If my voltage goes to say 100 vac and the Autoformer kicks in, I understand that the amps increase. W= VxA. So if I pull more amps, wouldn’t I be limited by the 50 amp breaker at the pedestal? So using that logic, If the campground is properly configured for power and 50 amp pedestals, you really should not overload the system. In theory, the system should not be affected, however I am sure most systems are not built for full 50 amp draw on a continuous basis. Interested in your thoughts!
Sounds to me that the campgrounds need to be brought up to code and the autotransformer wouldn’t be needed.
I look forward to your test results. Thanks for your research and dedication.
I suspect that our RV electric appliances have a shorter life from poor campground voltage. Wonder if a test could show if an AC run at 120 volts lasts longer than one run at 110.
That would be a pretty expensive test to do. My wife already complains that the monthly electric bill goes up by $100 to $200 when I’m doing load testing, I’m sure this would take a few thousand hours of running time with two identical air conditioners, one running on 120 volts and the other on, say, 105 volts. You would want to monitor current as well as voltage, and a few temperature monitors along with a FLIR camera doing time lapse photos would be good data. Yikes…. That’s a lotta data gathering tools that I suspect even Dometic doesn’t do. As I’ve said before, I need a bigger lab and a budget. Then I could do some really interesting stuff.
Plan A: Use your autoformer and have a good day.
Plan B: Have your A/C struggle, drawing serious amps, and burn out like the others.
Plan C: Sit in the dark and heat since your overpriced EMS shut you down.
Does anyone believe that a campground full of struggling, over-heating and damaged air conditioners is a safe thing?
The point is I don’t know how well this works to reduce overall current. That’s what Hughes claims and that’s why I’m doing this test.
Mike, you are a rock star. Oh, wait a rock star equipment guru.
Actually, I am a rock star. Or at least I was back in the ’70s when I was crazy enough to jump through fireballs in a chrome jumpsuit and crowd surf with a cut Mini-Moog synth strapped around my neck. Seriously…
Any pictures? It’s nice to read about another side of you, other than the RV electrical genius we’ve come to know you as! 😜
I’ll have to dig out a few. I fancied myself on the keyboards as a cross between Rick Wakeman and Keith Emerson, with a little Jon Lord and Ray Manzarik thrown in. Oh, me and Frank Zappa as well as Alan Parsons and Roger Nichols were engineering brothers under the hoop. All of the above engineers and musicians were great and helped inspire me to play and record music better. And music is the reason I got interested in electricity and electronics.
I’ve had a 50 amp Huges transformer for the last 5 years of our fulltiming & it’s the most wonderful piece of equipment I’ve added, along with my air conditioner Soft Start module. We’ve been in so many parks where the voltage drops well below 110V when the air is running, especially when the parks are full on a hot day. The transformer does a wonderful job of bringing the voltage back up to an acceptable level. My 5th wheel set up allows me to have the transformer inside my basement, near the electrical plug in point of the rv, so no one knows I am using a transformer.
I’m right there with ya, Fred. I was able to shoehorn mine in next to my cord reel so it’s never seen. It will be interesting to read what Mike comes up with, however.
Fred, after encountering several neighbors at several campgrounds complaining to me that my (visible next to the pedestal) Hughes was stealing their power… I did some rewiring inside my electrical bay and just installed the Hughes in there (out of sight
). Just looks like a 50amp cord coming out of the RV directly to the pedestal… No More Complaints for the last 3 years!
If you’re paying for 30 or 50 AMPS, you can legally use it. Are we going down the road of banning things because campgrounds have outdated electrical systems? Thanks to Mike, I began monitoring campground voltage last Winter. My wife said it nearly ruined our camping because I saw how terrible campground voltage was and was reluctant to turn on the AC. Prior to being “educated “, I was dumb and happy and ran AC as much as we wanted.
Actually, transformers are currently banned in campgrounds as of the 2020 NEC. It’s only a matter of when each state will adopt the 2020 code. Now seriously folks, I’m on your side. But I need real empirical data to prove or disprove the value of this technology. I can’t use anecdotal evidence at all since everyone who owns a Hughes Autoformer is emotionally attached to it. I’m just a scientist/engineer and occasionally a rock musician. Don’t worry, I’ll get to the truth of the matter.
There is a breaker on the pedestal, anything that doesn’t trip it should be legal.
Again, this is not a legal thing, it’s a code thing. And I agree that campgrounds should supply you with the power you’re paying for. But fact is, many of them are in serious trouble trying to supply power through an antiquated power grid. I need to learn the whole picture before I can make recommendations to the industry.
Obviously anything plugged into a 30A or 50A circuit breaker is not going to draw more than 30A or 50A, except for a very short duration. So I don’t understand the argument against them.
More on this later….
The first time I used my Hughes at a campground was last weekend. I tried it at home but it never went into boost mode. So at the campground, while I was working at the picnic table, I had a multi meter plugged in next to me. I could hear the AC get louder and seem to slow down. I looked at the meter, and watched the voltage drop. As soon as the voltage hit 112, it jumped to 120. I could hear the AC run normal as it was breathing a sigh of relief as it wasn’t struggling anymore. For me, if it will extend the life of my RV components, it’s worth it. Next time out I’m taking my ammeter with. I’m also going to be trying something else. I ordered a 50 amp dog bone adapter with 2-30 amp outlets. I plan on seeing if 1 leg has a higher voltage, I plan on plugging into that one which should help the campground situation. Unless the installer took time to split the 30 amp legs from site to site, 1 side of the 50 amp should have higher voltage.
Actually, best practice is to swap the two hot poles from pedestal to pedestal, and that will even out the 30-amp drooping leg problem. But I don’t think many campgrounds know this free trick to reducing voltage drops.
Yes exactly what I meant. reversing legs from pedestal to pedestal would split the loads, so to speak. But, when most of these systems were put in, who would think it would be an issue.
It would actually be doable for 3 or 4 hours of technician or electrician time for each campground “loop”. I would think 30 minutes per pedestal would do it. Of course you would have to power down that particular loop for the duration of the work and do proper LOTO (Lock Out Tag Out) safety precautions on the service panel breakers. But doing it would really help the 30-amp overload problem a lot and not cost too much money.
I do it throughout our park and it make a big difference.
Alternated the feeds 35 years ago to help balance the loads. Problem is that most of us never envisioned three air conditioners, electric water heaters, electric unit heaters, washers and dryers, electric frying pans, electric hair dryers drawing 15 amps, etc., etc. now being included in RV’s. Makes it cheaper for the manufacturer to build but much more expensive for a campground to meet these requirements. Campgrounds that properly meet these requirements will need to fairly charge to meet these demands.
It’s a simple thing that could have been done during the original campground power installation. But you are 100% correct that nobody anticipated the huge increase in RV power demands over the last few decades. I ran a poll last month which showed some 59% of RVers had 1 air conditioner, 30% had 2 air conditioners, and 5% had 3 air conditioners. That leaves only around 5% of RVers who don’t need any air conditioner power. I’ll bet if we could take a poll from 35 years ago there would only be a relatively small percentage of RVs with a single air conditioner, and the majority wouldn’t have any air conditioners at all. I’m doing my best to figure out simple maintenance techniques that can help reduce lost power, but there’s no simple answer for this problem. Interestingly, I recently read a report which stated that 12% of the world’s energy usage is spent on climate control (air conditioning).
I’ve never understood the campground’s concern with autotransformers. If it is plugged into 30 amp service at the pedestal then it isn’t going to draw more than 30 amps no matter how hard it tries to offset the low voltage condition. If the campground’s electrical infrastructure can’t handle the rated amperage that would seem to be their problem.
Three RV’s are having electrical problems but one is not and it has an Autoformer sitting at the pedestal. Clearly, that RV is stealing power from the other three and causing the complaints and the problems. (insert “rolls eyes” emoji here)
It’s a lot easier and cheaper for a campground owner to deflect blame away from themselves than to correct the problem. Because if everyone is having problems, it must be the electric company’s fault, right? (insert “rolls eyes” emoji here)
That’s why mine is mounted inside the electrical bay. Out of sight, out of mind, and when people say they’re having electrical problems I just nod my head and say nothing.
To be fair, the National Electric Code, which is neither “national” or a “code”, does not require that 100% of the pedestal rating be available to 100% of the sites and 100% of the time. I think the current requirement is 80% capacity because they understand that no one runs at 100% capacity on their entire system.
Actually, the National Electrical Code is exactly that. It is a national codebook of best practices, but it must be adopted by each state and locality before it becomes “the rule”. Just because they tell you something you don’t want to hear doesn’t mean it’s wrong. In fact, there are hundreds of very smart people on the code committees who continually improve electrical safety. I personally think there’s a lot of things that should change in the code about how campground power is designed, but until I gather enough empirical data on actual usage patterns, they’ll still be using derating charts that are antiquated. Note that I don’t have a horse in this race, except for finding truthful answers to important questions. And I think the questions about campground power are vitally important to the RV owners as well as campground owners and RV manufacturers. Stand by for some interesting data in a few weeks.
Fact is, Hughes misrepresented how their Autoformer works in their sales literature, saying that it could restore 3,600 watts of power from a 30-amp pedestal that had 100 volts. I called them out on this obviously incorrect statement years ago and offered to help them rewrite their literature for free. But they ignored me until someone on the NEC panel got wind of these false claims and decided that autotransformers won’t solve low campground power issues. Much more for me to study, and you can expect a 100% truthful report from me in a month or so. Right now I won’t argue the pros or cons of their Autoformer because I haven’t tested one yet. And I only write about things I can test.
Mike,
I can’t wait for your review! This week during days with temps in the 100 degree range, voltage inside my rig averaged from 108 down to 98 volts during peak usage hours. My ems shut down the rv at 102 but by then I shut off both ac’s and other big loads…then sat outside in the shade. My rv got to 90 degrees inside and I wasn’t able to use my ac’s until around 8pm when voltage stopped sagging and returned to a range around 110 volts. Please, please do this review asap- I want to be able to use an Autoformer- or a competing product.
Working on it. Low voltage (brownouts) in campgrounds has become an escalating issue over the last few decades beginning when RVs added more air conditioners and campgrounds became more crowded. Unfortunately, nobody identified the problem until it has become critical. Now I’m trying to figure out ways to improve the situation without having campgrounds go bankrupt trying to correct their low voltage brownouts.