I'm tired... of RV resort excuses for voltage

/rant on

Over half of the RV resorts I frequent have low voltage. I've seen voltages under 100 volts, when powering up the microwave. It's one of the reasons I have the microwave on the inverter side of the 120 volt system. RV techs warn RV'ers that continuous operation of motors under 108 volts will damage and shorten their life expectancy. I recently purchased a Hughes Autoformer to combat the problem. Autoformers boost the voltage by two percent whenever they are plugged in, until the voltage gets to 116 volts, then a boost feature kicks in, boosting the voltage by ten (10) percent. When at 116 the voltage will magically jump to 127 or 128 volts, which everything happily consumes.

We as consumers have been slowly led to believe 110 volts is normal, IT IS NOT.. Check your labels, 120 volts is what everything has been designed for, and the appliances are happy with anything up to 132 volts, 135 volts is when most overvoltage situations kick in. Voltages lower than 120 lead to more heat, and then lead to shorter life of the appliance. It's a conspiracy, shorter life of product means more sales over the consumers life, and it's all about money, folks. /rant off

A friend emailed me a question recently.

"Is the autoformer the voltage regulator/booster device?
Why are you getting it? I know I have hit a few older parks with shakey power, is that why?
They looked kinda pricey just for the voltage regilator.
Just curious and also where you gonna put it?"

You hit the nail on the head, unfortunately the the majority of the parks I've stayed in have low voltage. I define low voltage as anything under 110 volts. It's one of the things I keep track of.

As you may or may not know, in a travel trailer there are two types of loads, resistive and inductive. That is, heaters/lights/fridge (resistive)(fans-inductive) and air conditioning/ microwave (inductive), the converter (120 to ~12v) is inductive. Getting a little deeper into electric theory, Power is made up of two things, the voltage and the amperage. They have a direct relationship as expressed by the formula (P=EI) (P)ower is expressed in watts, (E)lectro motive force is measured in voltage and I (current) is measured in amperage.

Resistive loads are usually happy with whatever they are fed, if they get low voltage, they may be a little dimmer, but it doesn't hurt the resistive load, the amperage/current is used to heat directly. (an incandescent light bulb heats a wire until it glows and gives out light.)

However, most lights in trailers are 12+- volts, so the actual 120 volts doesn't affect brightness or performance.

Onto inductive loads, anything with a motor or transformer, they are most happy and will last longer with higher voltage and lower current/amperage. The reason is current flowing through a wire heats it to some degree, resistive loads depend on the concept, unfortunately the motor/transformer does not need heat, it literally can destroy the motor (usually by melting the wire covering, be it enamel or vinyl/plastic/rubber and shorting out the device.) Motors and transformers in converters are wire wrapped devices and a short (or open) makes it not want to work, (an open causing the current to stop flowing, and a short causing the current to flow more with the possibility of fire.)

Motors need a certain amount of Power to run, for an easy example, say a motor requires 1200 watts of power, that would be 10 amps at 120 volts. The motor is usually (if 100% duty cycle) designed to handle the amount of heat 10 amps produces. If your voltage drops to 100 volts, the motor now requires 12 amps to run continuously, producing more heat, and over time it will affect the life of the device because it's running hotter than design. However, the air conditioner (13.5k BTU) will pull about 23 amps/120 volts (~2800 watts) to start, then settle down to run at 10 amps. If starting at 100 volts, it will pull at least 28 amps, a great increase in amperage (and heat.) (remember, heat destroys)

By the way, these are real world figures for my trailer,(Nash 22H,) as I had some time and voltage problems on my hands in Rock Springs, Wy. The problems were cured by the power company changing the center tap on the pole transformer (a larger autoformer) and giving the house/shop it's rightful 124 volts.

To sum it up, higher voltages (to about 135v) are better because they produce lower current (heat.) The electric company doesn't care, they get paid for "power" (kilowatts actually). You ever wonder how they get away with using such small lines across the country to deliver it? They use the same theory, very high voltage and small current, (remember, current heats) and then use various transformers/pole transformers to reduce the voltage to something usable by us little guys.

The autoformer/power booster helps the trailer to be more reliable and your appliances to be longer lived. A popular booster increases the voltage by 10% whenever the voltage drops below 116v, ie: 116 + 11.6 volts = 127 volts, if the voltage goes to 110 volts (very common) your voltage would be 121 volts.

Contrary to popular belief and despite what park managers will tell you, an autoformer does NOT steal power, it merely makes what is AVAILABLE more efficient, the autoformer by itself only drops about 1 percent of the load making it 99% efficient.

So while in Palm Desert/Palm Springs, I installed my new (to me) autoformer.

Area formerly under the Jack Knife bed, (now storage area-see blog) where 120/12 volt wiring and panel are. Seems there is some room in betwixt those wires.

A slight modification to the cord box, a little insulation and presto, it fits along all the other wiring.


I converted the 30 amp power cord with appropriate plugs/receptacles so I can use any 30 amp extension. I can also bypass the autoformer if needed.

For a wiring diagram, see my other blog posts on installing the 3000 watt inverter.

I am not affiliated in anyway with Hughes Autoformer, Franks RV power booster, Surge Guard Voltage Regulators or Powermaster Voltage Booster.

By way of CV, I graduated from Denver Institute of Technology with an Electronic Engineering Certificate (AAS) and spent a couple of years working for Texas Instruments (North Building) in Dallas, Tx. A couple of years working on televisions and radios in Rock Springs, Wy. then years of hobby electronics, including hidden cameras, power supply's, building and troubleshooting my own computers, becoming a computer forensics expert, and designing simple circuits for jobs around the house/trailer.

Also see Valiant Sacrifice my hughes autoformer dies