AC vs DC Power Supply and Your RV’s Electrical System


Melody Kimball

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Melody enjoys translating dense technical topics into do-it-yourself guides. Her passion is empowering people for self-sufficiency and making informed decisions. When she isn’t climbing, sky diving, or traveling with her canine co-pilots, she finds foodie gems and customizes RVs to match lifestyle capability needs.

For those of us new to RVing, it may seem puzzling how the components inside of our home on wheels still function even when not plugged into a campground’s shore power outlet.

Houses are stationary in order to receive electricity, right? So how can our RV, with all its modern amenities, go just about anywhere and still have power?

Fortunately, your motorhome or travel trailer is engineered to take and make electrical power wherever you may roam. To understand this, you need to understand AC/DC power.

Why Is It Important to Understand RV Electricity?

Unless we’re in the middle of a power outage, we often take for granted electricity and the ways it improves our quality of life every day. Contrary to popular belief, electricity is much simpler to understand than you may think.

Whether you own, rent, or borrow your friend’s rig for the weekend, knowing the basics of how electricity works in your RV will help you safely operate and troubleshoot electrical components on your RV.

A Basic Understanding of RV Electrical Systems

A Class C motorhome at a campground
Keep your RV in great condition by understanding its electrical system (Image from Camping World).

RVs draw from three separate electrical systems to power the RV technology you use to conveniently travel in comfort.

  • The standardized 12-volt DC system (for anything in the “house” of the RV)
  • A 120-volt AC system (shore power)
  • An automotive DC system (for vehicle powertrain in motorhomes)

So, What Is AC/DC Power?

DC stands for Direct Current because the electrical current flows in only one direction. This type of current is routinely used on things that run off of battery power. In your RV, this means slideouts, interior lights, fans, power awning, etc.

AC stands for Alternating Current because the electrical current alternates (or changes) direction in a pulsating motion.

The collection of electrical systems of your RV are powered using a combination of AC and DC power.

Why Do RVs Have AC and DC Power?

With two types of electrical current, it’s natural to question:  Why don’t all electronic components run on a single type?

RV electrical systems are designed to operate efficiently in all the environments you might take your rig, whether it be to a developed campground or the middle of the desert. In order to do this, you need both AC and DC power.

Multiple configurations create energy efficiency, system redundancies, and circuit isolation. In short, it lets you utilize both AC power coming from shore power when you’re plugged in, and DC power from the RV’s batteries when you are not plugged in to shore power. It’s the best of both worlds.

Venn diagram listing RV House Electric-Powered Components drawing from either or both 12-volt DC and 120-volt AC electrical systems.
Venn diagram listing RV House Electric-Powered Components drawing from either or both 12-volt DC and 120-volt AC electrical systems (Image from Melody Kimball).

Shore power hookup lets you leverage the same power grid you would at home. Generators and solar panels allow you to make your own power from anywhere as long as you have an energy source, like gas, diesel, propane, sunlight.

Regardless of configuration, RV batteries are the heart of every RV electrical system across all RV classes. Inverters and converters are used to transform the electrical current from its original state (either AC/DC power) into the type of electrical current required to power specific components of your RV.

Basic Troubleshooting for Your RV’s Electrical System

First, figure out which electrical circuit is involved. The Venn Diagram above will help with this. Once you’ve identified what circuit you need to worry about, follow the flowchart below:

Flowchart - Basic Troubleshooting RV Electrical System
This flowchart should help you troubleshoot any basic electrical problems you could have (Image from Melody Kimball).

If It Is a DC Circuit

Check ground connection. When the grounding connection is the culprit, either the ground wire is loose or unintentionally inhibited by paint thickness or corrosion.

Not sure where to find the ground connection? Good Sam members can call the Elite Service Tech Advisor support line for a real-time, step-by-step troubleshooting walkthrough for your specific RV model.

Beyond the ground wire connection, the Elite Service Tech Advisor can also help you determine the next steps to fully or temporarily restore electrical function.

If It Is an AC Circuit

Check whether the outlet has Ground Fault Circuit Interrupter (GFCI) protection. A GFCI outlet is easy to identify because it has TEST and RESET buttons located in the center of the outlet.

You’ll need to find out if the GFCI outlet was tripped. GFCIs are designed to prevent electrocution and fire by detecting circuit overload, electric current leakage, and built-up moisture.

Circuit Overload

Circuit overload could trip either or both the GFCI and circuit breaker. The circuit breaker disrupts electrical connection when excessive current overloads the circuit. It is designed to trip before the wires’ heat level reaches dangerous levels.

If you believe circuit overload is your issue, then consider removing a power draw from that circuit. For example, if you have a coffee maker and a microwave plugged into the same outlet, they could overload the circuit and trip the GFCI or circuit breaker. So, you’d need to remove one of those items from that circuit.

Electric Current Leakage

Current leakage could be from things plugged into an outlet, the outlet itself, or the wiring of the RV. Check what you’ve plugged into the outlet first. If those look fine—no damaged cords or plugs—then move onto the outlet. If the outlet seems to be working properly, it could be the wiring of your RV.

Determine whether you have the skills, proper tools, and safety gear before attempting to troubleshoot wiring issues because of potential injury—any electrical shock is dangerous.


Moisture accumulation is caused by humidity and splashing liquid. Both of these can cause a GFCI to trip.

Reduce moisture build-up by promptly cleaning up spills, using dehumidifiers, desiccants, and opening windows at times. Anything you can do to keep your outlets dry will help.

Easy Math: Exceeding Available Power

If you think your issue is due to circuit overload, there’s an easy way to be sure. Your RV’s circuit only has so much power to give. If you have too many things plugged in and drawing power from that circuit, you will have an issue. That’s where a little simple math comes in.

You can do the following formulas to determine how much power your circuit has to give. Then look at the power draw the items you plugged into the circuit will create. From there, you should be able to tell if you’re overloading the circuit.

If you’ve ever purchased or changed a lightbulb, then you’re already somewhat familiar with watts, volts, and amps. All three factors are important. Electrical power is measured in watts. Electrical current is measured in amps. Electrical force is measured in volts.

To use the formulas for determining how much power your circuit has to give, look at the numeric ratings of the connected components and plug those numbers into the following equations.

  • Maximum Amps = The amount of electricity the RV receives from the power source
    For example, shore power would be 30 amps or 50 amps. Moochdocking power would be limited to 15 amps usually.
  • Amps = Watts ÷ Volts
    This calculates the amount of power draw created by a specific component. Divide the component’s watts by the volts for the circuit.
  • Total Amps = Add up the Amps for each connected component
    This calculates total power draw from the circuit.
  • Remaining Amps Available = Maximum Amps — Total Amps
    This calculates how much power your circuit has left to give.

If your Total Amps exceeds your Maximum Amps, you’ll overload the circuit. That means you likely need to unplug some things from that circuit.

Simplified: RV Electricity

a family enjoying some outdoor lighting of their RV
When you better understand your RV’s electrical system, you can camp worry-free (Image from Tyler Cave).

The inner workings of RV electricity are actually relatively simple. What creates the appearance of complexity are the multiple customizable configuration options available to design your RV electrical system to match your power consumption needs.

Adding to the illusion of complexity are acronyms and shorthand usage used to describe units of measurement as well as the components (end items and piece parts).

What you really need to know is that your RV operates with AC and DC power, and be able to identify which electrical component or system runs on what type of current. As always, if you would like to, you can schedule an appointment at your nearest Camping World location or chat with our service team about your RV issues.

  • Comment (5)
  • Cliff says:

    I have a 2001 rexhall aerobus. I understand difference between ac and DC power. My problem is I overloaded an outlet circuit. My breakers aren’t tripped but half my outlets work and other half don’t. I only found 1 gfci outlet, it was not tripped but I tried resetting anyway… luck. There must be a reset somewhere I’m missing. Any ideas? Oh yeah bus is plugged into 50amp shoreline.

    • Hi Cliff,

      Have you checked the breakers at the power pedestal as well?

      I reached out to our technical service team and they also cautioned that the problem could be related to a generator transfer switch, as only one of the two legs is receiving AC power at some point.

  • M Heisler says:

    Being aware of the need for DC for the controls (and propane ignition) on the furnace, refrigerator and water heater is important when dry camping. They add to the battery drain. We tend not to think about it when on shore power but it’s good to know you still need the DC for the controls. Thanks

  • Robin Capps says:

    Wow this is great. I was gifted with an older (91) well preserved RV. But NO MANUAL. No schematic map. Manage to get all bulbs working. Broken, untaped or capped. But gosh, if anyone can find a’91 Gulfstream Highrise could sure make life easier. Even the company says they don’t. Am a ham radio operater. Can anyone help?

  • Kelsey Glennon says:

    Great tip!

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