What an RV generator does and why you might need one
An RV generator is a machine that makes electricity when your RV is not plugged into shore power at a campground. It runs on fuel — usually gasoline, diesel, or propane — and produces the power to run your lights, refrigerator, air conditioning, and other appliances while you are parked away from electrical hookups.
Most RVs have a battery that powers basic systems like lights and the water pump for a few hours, but a battery alone cannot run an air conditioner or microwave for long. A generator fills that gap. If you plan to camp in places without electrical hookups, or if you want to run air conditioning or other high-power devices while boondocking, a generator is the main way to do it.
Some RVs come with a generator already built in. Others do not, and you can add a portable generator or have one installed. The choice depends on how often you camp without hookups, what appliances you want to run, and how much noise and fuel consumption you are willing to accept.
Key Takeaways
- RV generators produce electricity from fuel so you can run appliances and air conditioning when not plugged into a campground's electrical system.
- Built-in generators are quieter and more convenient but cost more upfront and use fuel even when you are not using much power.
- Portable generators are cheaper and only run when you turn them on, but they are louder and take up storage space.
- Generator size is measured in watts; most RVs need between 3,000 and 7,500 watts depending on which appliances you want to run at the same time.
- Inverter generators are quieter and safer for sensitive electronics than conventional generators, but they cost more.
Built-in versus portable generators
A built-in generator is permanently mounted in your RV, usually underneath or at the back. It runs on the RV's fuel tank (gasoline, diesel, or propane) and starts automatically or with a switch inside the RV. Built-in generators are quieter than portable ones, they do not take up storage space, and you do not have to set them up. The downside is that they cost several thousand dollars to install, they use fuel even when you are only running a few lights, and repairs require a technician who knows RVs.
A portable generator is a separate machine you can move around. You set it outside your RV, plug a heavy-duty cord into it and into your RV's inlet, and turn it on when you need power. Portable generators cost much less — often $500 to $2,000 — and you only run them when you actually need electricity. The trade-offs are noise (they are significantly louder than built-in models), the need to store and transport them, and the risk of running out of fuel if you forget to refill.
If you camp mostly at RV parks with full hookups, you may not need either. If you boondock regularly or want to run air conditioning off-grid, a built-in generator is more convenient. If you camp without hookups only occasionally, a portable generator is usually the better financial choice.
Understanding generator size in watts
Generator size is measured in watts, which describe how much power the generator can produce. A larger wattage means you can run more appliances at the same time. Most RVs need between 3,000 and 7,500 watts.
Here is why size matters: when an appliance starts up, it draws much more power for a moment than it uses while running. An air conditioner might use 1,500 watts while running but draw 3,000 watts when it first turns on. If your generator is too small, it will shut down or fail to start the appliance. If it is larger than you need, you are paying for power you will never use.
To figure out what size you need, add up the wattage of the appliances you want to run at the same time. A microwave uses about 1,000 watts, a refrigerator about 600 watts, an air conditioner about 3,000 to 4,000 watts at startup. If you want to run an air conditioner and a microwave together, you need at least 4,000 to 5,000 watts. If you only want to run lights, a refrigerator, and a water pump, 3,000 watts may be enough. Check your appliances' manuals or the labels on the back for their wattage.
Inverter generators versus conventional generators
An inverter generator produces electricity in a way that is safer for computers, phones, and other sensitive electronics. It keeps the power steady and clean, which means your devices charge faster and are less likely to be damaged. Inverter generators are also quieter — often 20 to 30 decibels quieter than conventional models — which matters if you are camping near other people.
A conventional generator produces raw electricity that fluctuates slightly. This is fine for lights, a refrigerator, or a water pump, but it can shorten the life of a laptop, phone charger, or modern RV appliances. Conventional generators are louder and cheaper, but the savings usually do not make up for the risk to your electronics.
If you own a modern RV with digital controls, a smart refrigerator, or you plan to charge laptops and phones regularly, an inverter generator is worth the extra cost. If you only need to run basic appliances and do not care about noise, a conventional generator will work.
Fuel types and how they affect your choice
Built-in generators run on whatever fuel your RV uses — gasoline, diesel, or propane. Gasoline generators are the most common and cheapest, but gasoline can go bad if stored for months. Diesel generators are more efficient and last longer, but they cost more upfront. Propane generators are quieter and cleaner, and propane does not go bad, but they are less common and harder to find parts for.
Portable generators almost always run on gasoline. You buy fuel at any gas station and store it in a jerry can. The downside is that gasoline stored in a can degrades over time, especially in heat. If you store a portable generator for the winter, add fuel stabilizer to the tank and run it dry before putting it away, or drain the tank completely.
Some newer portable generators run on propane, which does not degrade. Propane generators are quieter and cleaner, but they are more expensive and less widely available. If you boondock in remote areas where gas stations are far apart, propane might be worth the extra cost.
Noise levels and campground rules
Generator noise is measured in decibels. A conventional portable generator at 20 feet away produces about 80 to 90 decibels — roughly as loud as a lawn mower. An inverter generator produces about 60 to 70 decibels at the same distance — more like a normal conversation. A built-in generator is quieter still, usually 70 to 75 decibels.
Many RV parks and campgrounds have rules about when and how long you can run a generator. Some allow generators only between certain hours, like 8 a.m. to 8 p.m. Others ban them entirely. Before you buy a portable generator, check the rules at the places where you plan to camp. If you camp at quiet or upscale parks, an inverter generator is nearly essential.
If you boondock on public land or private property where you have permission, generator noise is usually not a problem. But if you camp near other people, a quieter generator keeps the peace and makes your camping experience more pleasant.
Maintenance and how to keep a generator running
A generator needs regular maintenance to stay reliable. For a portable generator, change the oil every 50 to 100 hours of use, check the air filter before each trip, and run it for 15 to 20 minutes every month even if you are not using it. Before storing it for the season, drain the fuel tank or add stabilizer and run it until the carburetor is clean.
Built-in generators need professional service once a year or every 100 to 200 hours of use, depending on the manufacturer. You should also run them for 20 to 30 minutes every month to keep the engine in good condition. Built-in generators use your RV's fuel tank, so you do not have to worry about fuel going bad, but you do need to keep the tank at least one-quarter full so the generator does not suck up sediment from the bottom.
Neglecting maintenance is the most common reason generators fail when you need them. A few minutes of work each month is much cheaper than a repair call or a ruined camping trip.
Frequently Asked Questions
Can I run my air conditioner on a portable generator?
Yes, but only if the generator is large enough. Most RV air conditioners need 3,000 to 4,000 watts at startup, so you need at least a 5,000 to 6,000-watt generator to run it safely. You also cannot run much else at the same time. If you want to run an air conditioner regularly, a built-in generator is more practical.
How long does a generator run on a tank of fuel?
It depends on the size of the generator, the size of the fuel tank, and how much power you are drawing. A portable generator with a 5-gallon tank might run 8 to 12 hours at half load, or 4 to 6 hours at full load. A built-in generator using your RV's fuel tank could run much longer. Check the manufacturer's specifications for your specific model.
Is it safe to run a generator inside my RV?
No. Generators produce carbon monoxide, a deadly gas that has no smell or color. Always run a generator outside, at least 15 feet away from windows, doors, and vents. Never run it in a garage, basement, or enclosed space, even with ventilation.
What is the difference between running watts and starting watts?
Running watts is the steady power a generator produces. Starting watts is the extra power it produces for a few seconds when an appliance first turns on. When you buy a generator, make sure the starting watts are high enough for your largest appliance. A generator rated 5,000 running watts might have 6,000 starting watts.
Can I use a generator to charge my RV battery while boondocking?
Yes. The generator powers your RV's converter, which charges the battery. This is useful if you want to run the generator for a few hours in the morning to charge the battery, then turn it off and use the battery power for the rest of the day. It reduces fuel use and noise.