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How Do RV Inverters & Converters Work?

In RV living by Christopher SchopfLeave a Comment

If you’ve been doing research on RV and tiny home electrical systems, you know that they can run both AC and DC power.  You may have also discovered that they do this by using an inverter and a converter.

How do RV inverters and converters work on RVs? An inverter increases the voltage coming from the DC power supply and changes the current from running in one direction only to running in alternating directions.  A converter does the opposite. In simple terms, an RV inverter changes DC power to AC power and an RV converter changes AC power to DC power.

AC vs DC Explained For RVers

First, we need to understand a few technical aspects.

Then we can move on to explain how the inverters and converters function on our motorhomes and RVs.

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The term AC stands for “alternating current”.  This is because AC power is constantly changing between positive and negative. DC stands for “direct current”.  The reason it is named direct current because the power always runs from negative to positive and never changes.

According to Energy.gov, the United States used to run off of DC power but switched its electrical grid to AC power once it was established that the high voltages of AC power could be sent over much longer distances than DC power could.

In recent years, this has changed and DC power can be run over long distances at high voltages, but the AC power grid remains the same.

DC power has traditionally been used in smaller and more portable applications like batteries.

Now let’s get back to talking about RVs.

Since an RV is designed to run off of the electrical grid as well as a 12-volt battery, it uses both AC and DC power.

RV lights are usually 12-volt lights and some of the appliances can run off of 12 volts as well.  Other appliances like microwaves and televisions run off of AC power.

In order for an RVer to use their AC appliances while working from just their battery, they’ll need to use an inverter.  When RV’s are hooked up to the electrical grid at home or at a campground, they need to make use of a converter.

This converter will charge the RV’s battery and the RV will continue to run any DC appliances and lights without losing its charge.

AC power can be dangeruos.  A 12-volt DC battery, on the other hand, is not less dangerous.  Either way, extreme caution should be used when working with electricity.

Converters For RVs Explained

A converter is used to change AC power to DC power.  RV systems have converters built into them so that you can charge your battery while you’re parked at a campsite that has electricity.

There are many different types of converters but the one that is used in an RV is known as a controlled rectifier.  This is because the process of converting AC to DC power is called rectification.  Other types of converters include DC choppers, AC voltage regulators, and static switches.

An AC to DC power converter usually runs between $100.00 to $200.00.  The price changes based off of how many amps the AC converter can handle.  Here are two quick examples of AC to DC power converters.

  1. The PowerMax PM4 100 amp 110 Volt AC to DC Converter – This converter has a 100 amp DC power output and sell for around $170.00.
  2. The PowerMax PM3 35 amp 110 Volt AC to DC Converter – This converter has a 35 amp DC power output and sells for around $125.00.

You can find the actual prices here at Amazon.com.

As you can see, the higher performing converter doesn’t cost much more than one that is half as powerful.

Inverters For RVs Explained

An inverter is a type of converter that converts DC power to AC power.  RV systems use inverters to enable the battery to run AC appliances.  An inverter can only convert so many watts at a time so RVers need to choose an inverter that has a high enough watt rating to run everything they want to run at one time.

For example, a 1,000-watt inverter will not be able to run a 1,500-watt electric space heater.  A 2,000-watt inverter will not be able to run a 1,500-watt space heater and a 600-watt microwave at the same time.

At this point, you’re probably wondering why people don’t just buy 10,000-watt inverters so they don’t have to worry about power restrictions.  The reason for this is inverters with higher watt ratings also come at a higher cost.

They’re also larger in most cases and weigh more.

Even if you have a 10,000-watt inverter, you may find that your battery does not have enough power to run everything you want to run.  For more information on this, see our page on camper batteries.

3 Types Of Inverters

Inverters don’t just come in various watt ratings, they also come in different varieties.  There are three types of inverters to choose from.  These are:

  1. Square Wave Inverters,
  2. Modified Sine Wave Inverters,
  3. and Pure Sine Wave Inverters.

1) Square Wave Inverters

The square wave Inverters change the current but they do it abruptly.

This means they change immediately between positive to negative rather than in the smooth and natural way of native AC power.  While a square wave inverter is very inexpensive, it is not very useful to RVers since its power might not even run everything and can even damage AC appliances.

2) Modified Sine Wave Inverters

Modified sine wave inverters are a bit smoother than square inverters and have pauses built into them between direction shifts.  These are less expensive than pure sine wave inverters but more expensive than square wave inverters.

A modified sine wave inverter will run some AC appliances but not others.  This will vary between inverters as well as appliances.  Once again, these inverters may damage your AC appliances.

3) Pure Sine Wave Inverters

A pure sine wave inverter creates AC power that is the same as native AC power.

These inverters are usually quite expensive but they are worth the price as they will run all of your AC appliances without damaging them.

Pricing Examples for RV Inverters

EDECOA 3,000 Watt Power Inverter – Modified Sine Wave – This inverter is a modified sine wave inverter that can handle up to a 3,000-watt power draw.  It is currently selling for only $225.00.

Power TechOn 1,500 Watt Inverter – Pure Sine Wave – This inverter is a pure sine wave inverter and can handle up to 1,500 watts.  It is currently selling for $250.00.  As you can see, even though it can only handle half of the watts of the modified sine wave inverter, it is actually more expensive.

Power TechOn 1,000 Watt Inverter – Pure Sine Wave – This inverter is a pure sine wave inverter and can handle up to 1,000 watts.  This is currently selling for $170.00.
Lowering the power capacity by 1/3rd lowered the price by about 1/3rd.

What About Amps?

Amps also come into play when using an inverter.

This is because inverters are usually only rated for a certain amount of amps and the inverter may have a fuse that will blow if the amp draw is too high.

My recommendation is to buy an inverter that has a higher amp rating and watt rating than you think you’ll ever need.  This way, you won’t ever have to worry about what appliances you can use and when you can use them.

Additional Information on Inverters and Converters

One thing to note when using inverters or converters is that some power is lost through the conversion process.

Because of this, it is always best to use an appliance or light that is built to run directly off of the power source you’re using.

For example, if you have a solar setup and plan to run completely off of DC power, you’d be better off buying a 12-volt television over buying an AC converter to run a standard AC powered television.

Many RVs come standard with modified sinewave converters.  This is fine for the appliances that came with the RV but it might not be great for other electronic devices you bring into your RV.  This is especially true for people who are going to live full-time in their RVs.

Another thought to keep in mind is that a modified sine wave inverter may not hurt your device on the first try.  This means that you could run a humidifier off of your inverter for a month before it ended up ruining it and you’d never suspect it was your RV that did it.

Running On Solar Power?

If you’re running a solar powered system, you may not need to buy an inverter or a converter.

Solar panels run DC currents so you won’t have to worry about converting this power before it can charge your battery.  If you decide to use all DC appliances and lights with this setup, you won’t have to worry about an inverter either.  This is because the power from your battery will not need to be converted to AC before it can be used.

This being said, it is wise to add an inverter and converter to your system.

You never know when you’ll need to charge your battery using 110 volt AC power and you never know when you might want to charge an AC electronic.

In Summary

Inverters and converters are an essential part of any well-rounded RV.

These devices allow an RVer to run their lights and appliances regardless of what power source they are using.

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