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RV Electricity Basics

Whether you are renting an RV on Outdoorsy for the first time or purchasing an RV for travel or to rent out to others, it’s wise to learn the basics of RV electricity. This article is designed to give you a basic understanding of your RV’s systems, how they work, and what to be aware of in terms of safety. Long-term care and maintenance is a more complicated subject you should look into, if and when you become an RV owner.


The vast majority of RVs have two electrical systems. There is an AC (alternating current) system that is very much like the one in a typical home. There is also a DC (direct current) system that works very much like your car does. The AC system is powered by plugging your trailer into an external AC power source.  Your DC system runs off one or more battery systems installed in your RV. Your lights, water pump, fans, TV, and radio run off the DC power system. Big appliances like the Air Conditioning, Microwave, and your power outlets, run off the AC power system. The AC system is capable of generating a lot more power than the DC system which is limited by your RV batteries.

The two systems are connected such that if you have AC power coming into your RV it will charge up the batteries for the DC system. The device that does this is called a “Converter.” Most RVs also have an “Inverter” which is a device that turns DC power into AC. RVs with an inverter will have specially marked wall outlets that run on the DC battery system but provide AC power.

Most RVs are set up so that if you have shore power (more about that later) you can run pretty much everything in the RV. If you don’t have shore power, then you are running off the DC system which can run the essentials like the lights and water pump for a few days, provided you are frugal about it. Plugged in: all the comforts of home. Off the grid: just the basics, and use them sparingly.

Illustration by: Sigfried Trent

Power Sources

Let’s take a quick look at each of the sources of Power for an RV.

Your Batteries

Every RV will have a set of batteries installed. These provide your RV with a source of power when no external power is available. The amount of power the batteries can provide on their own is fairly low. They can run the lights, water pump, and small appliances for the better part of the day, but that is about all. They can’t drive the AC or Heating systems and will drain quickly when using the microwave or other plug-in appliances.

Your battery is charged any time an external power source is connected to your RV. This includes shore power, generators, vehicle engines, and solar. When you are in motion, your vehicle engine will be charging your battery.

Shore Power

Shore power is when you can plug your RV into an AC electrical grid. The available power you can draw on is measured in Amps. Common RV connections are 30amps, and 50amps. You can connect your RV to a line running from someone’s house, but use caution. Home outlets are generally only 15 amps.

Your RV will be set up to either use 50amps or 30amps. Bigger RVs are usually set up for 50amps. You can connect your RV to a lower Amp power source, but if you aren’t careful it can be dangerous. If you are connected to a lower source than your RV was designed for, you can damage the electrical systems if you try to draw more power than the shore power line is rated for. Typically the worst that happens is you blow fuses, but you could damage the power source or your trailer.

When you connect to shore power at an RV park, there will be a circuit breaker on the pedestal. Remember to turn that on after you hook up, and turn it off when you disconnect to leave.

Left to Right: Water inlet, outdoor shower, 50Amp Shore Power hookup. (Photo by: Sigfried Trent)


Generators work like Shore Power as they plug into your AC system and they provide AC power. Typically they don’t provide as much power as shore power does, but that really depends on the size of the generator. Generators are rated in watts rather than amps. A 1000w generator is about right for a small RV or if you don’t need to run major systems like Air Conditioning. A 3,500w generator is usually the next step up and can run most RV systems on most RVs. You can also daisy chain some 1000w generators to get more power.

Overdrawing a generator is not as risky as overdrawing shore power. If you try to overdraw a generator you simply won’t get enough power to make everything run properly. That could damage some appliances, though it is not likely.

Some motorhomes will have a built-in generator, separate from the main engine. These can be especially handy as they are insulated and thus not very noisy. The use of external generators is often limited by some parks due to the noise, especially at night. The most important safety rule for external generators is to never use them indoors. They produce a lot of carbon monoxide gas and it can become fatal very quickly in an enclosed space. Always run them outside.

Solar and wind

The important thing to understand about renewable energy sources is that they are designed to charge your battery, not to provide you with on-demand power. They generate DC current, rather than the AC you get from shore power and generators. Thus you are still limited by the amount of power your battery can provide, but you can keep that going far longer since you can recharge it over time. This gives you a renewable source of power “off the grid” – perfect for boondocking adventures.

The advantage is that your batteries are constantly being charged, the disadvantage is that you can’t run anything more demanding than you could normally run off the battery system alone. Typically that rules out the AC system, electric heaters, the microwave, and other high draw appliances.


Just like your house and car, RV’s have fuses that help protect the electrical system from overdrawing or power surges. If you lose power somewhere in your RV, chances are a fuse has blown somewhere. Chances are also good it blew because you were trying to draw too much power at once. You should make sure you know where the fuse panel is before taking out an RV. Most RVs will have re-settable fuses like those in your house, others may have ones you must replace like those commonly found in cars. If you have the replaceable kind, it’s a good idea to keep a few spares on hand in the RV.

Enjoying all the comforts of home while writing for Outdoorsy thanks to RV Electrical systems! (Photo by: Sigfried Trent)

Propane Vs Electricity

Your RV may have some appliances that can either run on Electricity or Propane. Heaters, water heaters, and refrigerators that can switch between the two are common. The rule of thumb with these is that if you are connected to shore power, use the Electricity option. If you are boondocking (camping off the grid), use the propane option. It really comes down to what do you have more of and which is cheaper – propane or electricity.

Surge Protectors

Some RVs will have a built-in surge protector, some will have an external one, and some have none at all. The purpose of them is to make sure the shore power is clean and steady before letting it into the trailer. This protects from power surges, both natural and unnatural. They are not essential, but they do help preserve the integrity of the RV’s electrical systems. If your RV has one of these, be aware that there is usually a short delay from when you connect power to when the surge protector allows power to the RV. Typically it is around 20 seconds. This can be confusing if you are not aware of it.

Final Thoughts

That covers the basics plus a little bit more. Generally, RV electricity is a no hassle situation, but it pays to know the basics so you can have a trouble-free adventure. If you want to learn more about basic RV systems, check out Learning Your Way Around an RV. If you want to dig a little deeper into electricity you can read more about it here.

Feeling charged up? Ready to zap boredom with a grand RV Adventure? Start your search for a great rental RV now!


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