Correct campground voltage is very important. If you attempt to operate your RV on low campground voltage you will damage your RV. For my RV I have decided to install a Hughes Autoformer to make the correct campground voltage every time I plug in the RV.
It took nearly two years to write the article about correct campground voltage. Here is a quick timeline.
It all started when we got our new to us 2008 Tiffin Bus. Unlike our previous RV, this one is power-hungry mostly because it has a residential refrigerator. Here is a link to the story. Our New RV
About three weeks later our air conditioner failed and we had to replace it. During the conversation with the technician, he mentioned that they fail due to prolonged operation and getting too hot. I thought it somewhat amusing because you don’t run the air conditioner when it is cold outside. This was the first time I heard of low voltage operation creating more heat. At the time I didn’t know you could correct the campground voltage.
During the first year of owning our power-hungry RV, I started occasionally hearing our air conditioners slow down and they were not putting out as much cold air. This was because of low campground voltage but I didn’t know it at the time.
I became suspicious when I installed a full-time voltmeter to monitor the problem and could occasionally see the brownout voltages. When this happened, the air conditioner would slow down. The low voltage slowdown never happened when we were operating our RV either from our generator or from solar but only when we were plugged in at the campground. Although you can’t call it correct campground voltage both my inverter and generator put out the correct voltage.
So I got a Hughes Autoformer to correct campground voltage back to voltage within ideal limits (this is the grey box in the picture above). I didn’t want to replace air conditioners due to pre-mature failure. They are expensive and because of Covid-related supply chain issues, they are hard to get.
About six months ago (about six months after I installed the Hughes Autoformer) I wrote the article below about correct campground voltage and offered it to FMCA to publish.
So this article was picked up in its original form by the Family Motor Coach Association Family RVing magazine and published in the May 2022 edition.
The difference between this post and the FMCA published article is that I am able to include a few more words and some more pictures. Extra information in this post can be identified by the stars. (***) The other difference is that not all readers of this blog are members of FMCA. Typically articles like this only appear in the FMCA magazine, but since I wrote it, I can share it here.
We were not compensated by FMCA, Hughes, or anyone else for our article.
FMCA is a wonderful RV club. We are proud to be members. Family RVing is their first-class RV print magazine. A couple of years ago we were lucky to be chosen for the very first non-professional cover photo. Here is a link to our article about the cover photo. We made the cover photo
If you are an RVer, I endorse membership in the FMCA RV club. Here is a link to the FMCA website. FMCA
Boosting low campground voltage
Article by Scott Fox FMCA Family RVing Magazine, May 2022
Voltage spikes receive considerable attention, but low voltage also can cause damage. The Hughes Autoformer is designed to combat that issue.
Campground voltage can be very low – Why is this a problem?
What is the ideal campground voltage? If the campground voltage is low, can you boost your voltage? Why would you want to boost your voltage? What is an RV Hughes Autoformer? Do I need one? How does it work?
We have installed a Hughes Autoformer voltage booster on our RV, and after researching and using the product, I’d like to answer the above questions and explain why you might consider adding one to your RV as well.
*** Picture of my full-time voltmeter showing low voltage. ***
A Hughes Autoformer plugs into the electrical pedestal at the campground, and then the RV power cord plugs into the Autoformer. Because I wanted to keep the Autoformer inside the RV, I mounted it in one of our storage compartments between the power cord and RV – rather than between the electrical pedestal and the cord. To do this, I cut the power cord inside the RV and hardwired the Autoformer into the cord before the automatic transfer switch.
In the unlikely event that you never plan to plug into a campground electrical system, you do not need an automatic transfer switch or a Hughes Autoformer voltage booster. But if you use campground electricity, this device can be a valuable addition to your RV.
What is the ideal campground voltage?
*** What is the correct campground voltage? Is it 110-volts or 120-volts? ***
The voltage delivered to your house (or RV) is ideally 120-volts. (In the U.S. we use a split system of two 120-volt wires to create the possibility of 240-volts.) Acceptable voltage is a range between 110-volts and 120-volts. Some appliances can function at voltages down to 108-volts. Voltages up to 132v typically will not cause damage. Most appliances require a minimum of 110-volts and ideally will be 120-volts.
*** Picture of the inside of my 50-amp electrical plug. ***
A low voltage situation exists below 110-volts and is considered a “brownout” situation. All lower voltages cause higher amperage draws for motors. The amount of effort (load) required by the motor doesn’t change.
Think of the load (the device you want to operate electrically) as a weight on the end of a lever. If the lever is long (higher correct voltage) then the weight will be easy to lift with a given force (current). If however, the lever is short (low voltage) then the load will require more force to lift (higher current).
Loads do not change when the voltage changes. Assuming the voltage remains low, the current required to operate the load increases. The problem is that increased current causes increased heat associated with the increased current.
Voltage, amperage, and watts
The relationship between voltage, current, and watts is simple. The one thing to remember when discussing electricity use is that loads (watts required) don’t change. A 1500-watt load requires 1500 watts (of energy) to run. The two variables are voltage (potential energy) and amperage (current). If one goes up, the other can go down and still operate the same load. To run a 1500-watt load at 120-volts you need 12.5 amps of current. To run a 1500-watt load at 110-volts you need 13.63 amps of current. The issue associated with using extra current is that extra current creates extra heat. Extra heat leads to accelerated wear.
Current and resistance
As current increases, resistance to the flow of the current increases. As current increases in a river, resistance creates erosion on the banks of the river. In terms of electricity, resistance creates heat both in the wires and in the devices that the current is powering. In motors increased heat leads to decreased efficiency and decreased lifespan. Increased voltage decreases current and decreases heat due to the decreased resistance.
*** Picture of the inside of my transfer switch. ***
***Can you correct low campground voltage? yes, you can ***
More than a transformer
The primary component of a Hughes Autoformer voltage booster is a transformer. Almost all transformers are used either to step up voltages or step down voltages. The power company uses transformers to change the voltage before it enters your house. Without transformers, we would not have an effective electrical system anywhere in the world.
The Hughes Autoformer voltage booster is a special type of smart step-up transformer. The voltage booster takes a lower voltage and increases it, sacrificing a little of the available current that is used to power the device. This potential current loss is not significant. The greater efficiency associated with operating at the correct voltage makes up for most of the current loss.
Not an autotransformer
The Autoformer is not an autotransformer. It has multiple windings, whereas an autotransformer has a single winding with multiple taps that allow for different voltages. Without multiple windings, any electrical failure in an autotransformer can be a significant safety issue.
*** A transformer will provide electrical isolation between its windings. An Autoformer does the same thing the same way. An autotransformer does not provide electrical isolation. The names are almost the same. It is important not to confuse the two words or think that the devices are the same thing. An autotransformer is not an acceptable way to correct campground voltage. ***
An autotransformer, with its single winding, does not provide for isolation between source and output. Thus, a failure in an autotransformer can result in full input voltage being delivered to the output when not needed, resulting in undesired high voltages.
*** Picture of my electrical compartment. The transfer switch is at the top left. ***
As a multiple-winding, computer-controlled, smart transformer, the Hughes Autoformer is designed to provide additional levels of protection.
The output on the Hughes Autoformer adjusts by load demand and input voltage. When no extra voltage is needed, the voltage is boosted by 2 percent. When a larger boost in voltage is required, the extra windings on the output side of the transformer will engage and step the voltage up to or close to the desired 120-volt output (10 percent).
Why do I need it?
As the number of RVs in a campground increases, the additional occupancy increases the amount of electricity required from the campground electrical system. Each additional RV in the campground adds to the load. And since most campgrounds were not designed for the new, more power-hungry RVs, their electrical systems may not be sufficient to accommodate the increased number of users. When this happens, voltages drop and can endanger every RV in the campground.
*** If the campground voltage is low, appliances will run at the lower voltages by drawing more current. This is because the load required to run the appliance doesn’t change. When this happens the extra current will create undesired extra heat in the circuit. Extra heat leads to extra wear on components and will lead to failure.***
When the electrical grid at the campground is perfect, you don’t need a Hughes Autoformer voltage booster. The problem is that in RV parks the electrical grid is undersized (for the number of RVs at the park) and not perfect. When an RV park is busy, let us say on a Saturday afternoon in the summer, there will be a large number of RVs all drawing power from the RV park electrical system, running air conditioners, and other electrical appliances.
*** Picture of the Autoformer installed inside my electrical compartment. ***
When this happens, the voltage at the park decreases, and because the voltage coming into each RV is now lower and the amperage used by each RV increases. As amperage increases, so does heat. As the voltage decreases each RV in the park is more and more at risk from low voltage damage. Each RV will use more current to accomplish the same task and each additional RV will add to the problem. Every inductive load (air conditioners) will get hotter due to the increase in current caused by the insufficient voltage.
Each RV that experiences low voltage will suffer electrical damage caused by the extra heat. This is not a club you want to join. Hence, it makes sense to boost your voltage and avoid the issue.
How does it correct for low voltage?
A Hughes Autoformer voltage booster corrects for the lower than desired voltage at the campground pedestal and increases the voltage inside the RV to protect it from low voltage operation. The Hughes Autoformer voltage booster corrects the RV park low voltage back to a more ideal grid voltage inside the RV.
Anytime the Hughes Autoformer voltage booster is plugged in, the voltages is boosted by a minimum of 2%. This will take an ideal input voltage of 120-volts to 122.4 volts making it slightly better. When the voltage drops to less than the acceptable 109-volts an extra 10% boost will correct this voltage back to nearly ideal 119.9-volts. Even if the voltage drops to a dangerously low voltage of say 96-volts then the Hughes Autoformer voltage booster will correct this by the same 10% back to 105.6-volts. As the voltage drops to these critically low levels, every RV in the campground will start to suffer damage. RVs equipped with electrical management systems (explained later in this article) will trigger their emergency power off relays and drop from the campground electrical distribution system.
What is the risk of low voltage?
During low-voltage operations, appliances such as air conditioners and refrigerators will run slower, get hotter than they normally would, and ultimately fail. This is because correcting for low voltage results in the electrical current increases, thus increasing the heat. Even if the appliance does not fail right away, the extra heat accelerates wear. This results in less effective operation. The accelerated wear increases the load and causes an even higher amperage draw, thus creating even more heat. All of this can be avoided with the correct voltage. Heat — especially excessive heat — is the enemy of electrical devices such as compressor motors in air conditioners.
Does it steal electricity from other campers?
Some people believe Hughes Autoformer owners use more than their share of electricity in a campground. They noticed that an RV with a Hughes Autoformer did not trip circuit breakers when their RV did. Thus, they concluded that the Autoformer allowed the RV to use extra electricity. Rather than using more electricity, the RV equipped with an Autoformer uses the electricity correctly, as designed. If you have a 30-amp RV on a 30-amp circuit, your limit is still 30-amps. The question is then, “How do you use the 30-amps?”
Do I need it on a 50-amp RV?
An RV with 50-amp electrical service can experience the same issues as a 30-amp RV. If the input voltage is low, it does not matter whether you have a 30-amp RV or a 50-amp RV. The company produces both 30-amp and 50-amp versions of the Autoformer.
Why is it more critical for a 30-amp RV?
That said, 30-amp RVs have more potential for electrical issues. This is because of the size of the wire in a 30-amp RV power cord. A 30-amp power cord typically has 10-gauge wires. My 50-amp power cord has 6-gauge wires. Each 6-gauge wire carries a maximum of 55 amps. Cord length also plays into this variable. Longer cords, and thinner wire = more resistance.
*** Picture of a 30-amp Autoformer.***
Fault Detection and Reporting
The Hughes Autoformer voltage booster will also detect faults in campground electrical systems. The display lights will reveal an open ground connection, an incorrectly wired neutral connection, and a reverse polarity condition. Any of these faults can damage an RV’s electrical system and appliances. The Autoformer includes both a surge protector and some functions — but not all fault detections — of an electrical management system (EMS).
What is an EMS?
An EMS is an electrical device that includes a surge protector and a relay that shuts off power to an RV when a damaging condition exists, such as low voltage. Conversely, the Autoformer corrects for low voltage instead of shutting off the power. Its fault detection feature reports malfunctions. The Hughes Autoformer does not replace an EMS but rather augments it.
The Hughes Autoformer’s voltage booster includes a built-in surge protector with indicator lights that identify if the unit has been hit by too many surges and can no longer provide protection. Not all surge protectors have an emergency power-off feature. Typically, this feature is part of an EMS that includes a surge protector.
Why not just use an EMS for voltage drops?
This is a fine idea for a temporary voltage drop. But do you really want to live without your air conditioner when what you really need is a boost in voltage to correct for an inadequate RV park electrical system?
Is an EMS still necessary?
I still have an EMS installed between the Autoformer and the automatic transfer switch on my RV. When a voltage boost is necessary, the Autoformer will perform this task before the EMS shuts down the power. If the Autoformer is unable to boost the voltage sufficiently, the EMS will protect my RV from issues not corrected by the Autoformer.
In my opinion, the Hughes Autoformer provides the highest level of correction and protection for my RV electrical system. I am glad I installed it.
About the author — Scott Fox is a retired Navy pilot and flight instructor who has been traveling full-time in his RV for almost four years and camping for more than 50 years. Scott’s blog, FoxRVTravel.com, shares stories and explains some of the more technical aspects of RVing.
That is it, the entire article about correcting campground voltage.
I want to thank the professional editors at FMCA for improving and helping me with the re-writes. Correct campground voltage is going to be a bigger problem as campground stays are being more popular. I suggest that at a minimum every RV have a robust EMS and that you test the electrical system before you plug in your RV.
This link is to the 50-amp Autoformer that we are using to get the correct campground voltage.
We also use the Hughes 50-amp Power Watchdog Smart Surge Protector EMS and are very happy with its performance but this article was about the Autoformer.
This is the Hughes voltmeter we have installed in our RV. Really on a 50 amp RV, you should have two of these voltmeters installed one on each 50-amp circuit.
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