Today’s RVs, whether they’re fancy motor coaches or simple campers, have a generous offering of amenities like stoves, refrigerators, air conditioners, etc. It’s a far cry from the early days of RV campers when all you had were a few lights powered by a coach battery.
To power all these modern comforts, you need an electric generator. This can either be a built-in RV generator or a regular portable generator used for camping.
In this RV generator buyer’s guide, we’ll dive into the need for an RV generator, the different types, and how to choose the best one for your vehicle.
If you spent serious money buying a motor coach RV, which comes with all those shiny electrical appliances, you’re squandering your investment by not getting an RV generator.
Now, if you own a small, towable camper or travel trailer, you may be fine without a powerful generator, but you could still use some basic backup power at least.
Sure, onsite power is an option at many campsites, but not all. If you're planning on taking your RV off the beaten path, then you can't count on there being shore power. Ensure your independence with a generator.
The first step in choosing an RV generator is distinguishing between the two types: built-in and portable.
RV generators are high-powered, typically offering at least 3,000 watts of juice. There’s no manual setup because they come with push-button-start from inside the vehicle. Many models can even adjust performance to altitude if you’re camping at high elevations, like the Rockies.
For those with a large Class A or Class C motor coach, built-in generators are certainly better, since a small portable one won’t handle everything you want to power. Yes, you can plug in a large, open-frame portable unit, but those weigh hundreds of pounds and are extremely loud.
The downsides are that built-in generators can be difficult or expensive to access, maintain, and repair. They also sit inside your RV and, although they exhaust outside, you should still set up a CO alarm in case of malfunction. In addition, keep your windows shut when running one to prevent exhaust from creeping back inside.
Portable generators eliminate these worries because they’re situated several feet away from your RV and can be easily accessed and maintained. Still, their smaller output and manual operation make them better for smaller Class B RVs or towable campers that lack their own fuel source.
The following chart summarizes the key differences between built-in and portable generators:
| BUILT-IN RV GENERATORS | PORTABLE RV GENERATORS |
|---|---|
| Integrated/Wired into RV | Connected from Outside |
| Automatic Setup, Push-button Start | Manual Setup/Start |
| Up to 12,000+ Watts of Power | Up to 8,000+ Watts of Power |
| Uses RV's fuel tank | Requires separate fuel tank |
| Difficult to Access/Maintain | Simple Access/Maintenance |
| Higher Risk of Exhaust Leaks | Lower Risk of Exhaust Leaks |
| Typically Costs More | Typically Less Expensive |
Whether you choose a built-in RV generator or a portable RV generator, the most important step is to size it correctly.
To size an RV generator, you need to figure out both its physical dimensions and electrical output.
1. Make sure your generator will physically fit into your RV. Take measurements in your RV generator's compartment to make sure you select one that will fit.
2. Determine your power needs. Add up the starting wattage requirements of every appliance you will run simultaneously. The total is the minimum wattage needed.
Your A/C unit will require the most power to run, and has a higher starting wattage requirement than running wattage. The number of air conditioners in your RV is therefore crucial to determining your power needs. For more information, read our article on powering an RV air conditioner.
Here is a list of common appliances and their average wattages:
Suppose you want to run an RV fridge, a coffee maker, a microwave, a portable fan, and a small tube TV simultaneously. If you add the starting wattages of those together on the chart, you'll get 2,620 watts. Any generator will need to handle at least that. For an idea of how many watts you may need, use our portable generator sizing calculator.
You should add about 20% to your maximum load. That way, your unit won't suffer the abuse of running nonstop at full power. In our example, you'd probably want at least a 3,200-watt generator. If you think you would ever want to run even more items, factor that into your calculations.
Some people ask how to size a generator for a 50-amp RV or a 30-amp RV. That's the wrong way to go about it.
A 50-amp RV requires a 12,000-watt generator to power everything at 240 volts and a 6,000-watt generator at 120 volts. Your RV may not have enough physical space to contain that large of a generator. That's why you should always start with physical dimensions and then figure out how much you really need to power at one time by adding up wattages.
Built-in RV generators run on gasoline, diesel or propane. You should match your generator fuel type with that of your RV. In most cases, your built-in generator will pull fuel directly from your RV's tank until there's a quarter tank remaining (to prevent accidentally going empty).
For towable campers without their own fuel source, you may opt for a liquid propane generator. Otherwise, go with the fuel that makes the most economic sense where you live.
If you choose a portable generator, your options expand to include dual-fuel generators, which can switch between gasoline and propane for added flexibility. Just remember that portable generators will need an external fuel tank that you'll have to manage.
Owners of gasoline-fueled RV generators need to be aware of some crucial federal regulations which we'll outline in the next section.
According to the Environmental Protection Agency (EPA), gas fumes produced inside the tanks of built-in RV generators must be captured and returned to be burned. This has lead to the manufacturing of EVAP generators that are specially designed to meet these regulations.
Typically, motorized RVs already have a built-in system that complies with these regulations, but most tow-behinds don't. The towable RVs require that you install an EVAP generator, certified hose, special fittings, a specially designed metal tank, and a carbon canister.
If your built-in system is missing any one of these certified EVAP components, you'll be subject to a hefty fine should you get stopped and inspected. So unless your gas RV generator pulls its fuel from the chassis fuel tank, you'll want to be sure you're compliant on the roadway so you don't get stuck with a major fine.
At the end of the day, choose an RV generator that will be practical for your needs and won't get in the way of enjoying your trip. Focus on embracing the great outdoors and making every day an adventure out there.
If you need more help choosing an RV generator, call us at 1 (800) 800-3317 to talk with an expert.