Your guide to purchasing an onboard RV generator

Thinking about installing an onboard RV generator in your motorized or towable RV? There are some key considerations when choosing the right RV generator for your needs, so our RV power generation experts have a breakdown of everything you need to know to make the most out of your Cummins onboard RV generator purchase.


What exactly is an onboard RV generator?

You can significantly improve your RV experience with an onboard RV generator. Installed RV generators travel with you everywhere you go, require less hassle, and offer unbeatable convenience.

Choosing an onboard RV generator saves you the hassle of moving your generator in and out as you change locations. Bolted directly into its own compartment, it’s always safe, secure, and protected from the elements.

An installed generator connects directly to your RV’s electrical system and starts with the flip of a switch. Because it receives fuel directly from your RV’s fuel tank, the need for extra gas cans and power cords is eliminated. You’ll save space and setup time, making life on the road easier and far less complicated.

Onboard RV generators can be used in both motorized and towable RVs. Cummins offers a variety of generator sizes and types to accommodate everything from Class B Vans and Class C RVs all the way up to Class A RVs and Fifth Wheel rigs with multiple AC units.

With an integrated and interconnected generator, you have power at the push of a button, just like at home.


Do you need an onboard RV generator?

In simple terms, you do not need to have an onboard RV generator to travel enjoyably. However, there are certain advantages to choosing an installed generator for your RV.

A fixed-mount RV generator gives you access to the power you need when you need it. Not only are they enclosed and protected - you won't worry about losing power, having to set it up or move it, nor will you need to manage gas cans and extra power cords.

For instance, the Onan QG2800i offers:

  • 60% quieter operation
  • 50% improvement in fuel economy in gasoline and, 25% in LP
  • 40% larger oil capacity
  • No daily maintenance requirements

An outstanding benefit of an onboard RV generator is that with the correct wattage, amperage, and voltage, you can run all of your appliances at once without worrying about losing power. That means your air conditioner, fridge, TV, and microwave can all be used simultaneously, just like at home. No more choosing what gets power or taking turns running what you need.

There are simple methods you can use to narrow your options: find the answers to common generator sizing questions here.


Portable vs. onboard RV generators

Still unsure if an installed or portable RV generator is the right choice for you? Here are some things to consider:


Onboard RV generators vs. Portable RV generators

Onboard RV Generators Portable RV Generators
No setup required. Require setup and take down.
Connected to your RV’s electrical system; start with the push of a button. Plug-in required and separate fueling.
Protected from the elements. Exposed.
Can be used while driving. Cannot be used while driving.
Can conveniently accommodate heavy power needs; sized and installed to meet your RV’s power needs. The more power you require, the larger the unit necessary to accommodate those needs.
Common installed generator power: 4000 – 12500 Watts Common portable generator power: 2000 – 4000 Watts
Protected from the elements, giving you the ability to run it regardless of weather conditions. Exposed to the elements, which can affect both performance and your ability to use it.
Offer the power you need wherever you go. Require setup and a power source; less convenient with more use restrictions.

Convenience is a key factor in choosing the generator type best suited to your needs. When considering the option of using a portable generator vs. an onboard RV generator, the key points to consider are convenience, setup time, exposure to the elements, the need for extra equipment, and more limited options for where you are able to stay.


Choosing the right size onboard generator for your RV

There are a handful of things to consider when deciding the ideal generator size for your needs. There are lots of options; however, at the end of the day, the size of the generator you need depends on the specific equipment you have within your RV.

Here is a breakdown of RV type and recommended generator wattage:


Type of RV Recommended Generator Wattage
Class B Van with one AC unit 2,500 to 2,800 watts
Class C RV with one AC unit 3,200 to 4,000 watts
Class A RV with two AC units (15,000 BTU each) 5,500 to 8,000 watts
Class A RV with three AC units (15,000 BTU each) 10,000 to 12,500 watts
Fifth wheel with two AC units 5,500 to 7,000 watts


Ranges vary based on your unique equipment, the two most important loads on your RV being the air conditioner(s) and the converter. The above table offers general guidance in making the best choice for your needs. We offer a deeper dive into determining just how much power you’ll need based on your appliances, accessories, and power requirements:, learn more here.

If you are new to RV generators, check out RV generator basics for an intro.


RV Generator Operation


Fueling your Generator: gas, diesel, or LP?

Fuel options are another important consideration in making your RV generator choice.

The most common are gas, liquid propane (LP), and diesel, but which is the right choice for you?

LP and gas generators have a lower initial cost than those requiring diesel fuel. The units themselves also tend to be smaller and lighter than their counterparts.

Another option for you to consider is an electronic fuel-injected (EFI) gasoline RV generator. The EFI technology used in Onan QG RV generator models uses the same technology as the automotive industry. EFI provides quieter operation than carburetor versions, and it is also more fuel efficient. The benefits of diesel generators include longer engine life, lower fuel consumption, and cost savings, as diesel fuel costs less than LP. A diesel generator gives you a common fuel system and the convenience of operating your generator from the vehicle’s main fuel supply. Many diesel RV generators, including the Onan Quiet Diesel Series, dramatically lower noise, vibration, and harshness levels.

The RV generator best for you depends on your use and your personal preferences.


How to install an onboard RV generator

While installing an onboard RV generator yourself is possible, due to the complexity of installation and critical safety precautions, most opt for professional installation.

If you do opt to install your onboard generator, there is quite a bit to keep in mind. Here are a few of the most important considerations:

As the installer, you are responsible for selecting the appropriate genset and proper installation. The set must meet the basic requirements of the Standard for Safety for Engine Generator Sets for Recreational Vehicles and will be specific to your particular rig.

Installation codes and recommendations can change from time to time and vary based on location. It is recommended that the installation standards listed here be obtained for reference.

Additionally, the location of your onboard RV generator is important as you ensure that you have proper access in an unobstructed space, so your generator is properly ventilated and safely separated from any flammable vapors. Proper mounting, insulation, and ventilation are paramount to achieving optimal performance and safety.

You can learn more about installing your onboard RV generator here or explore one of the 1,500 Cummins Sales and Service locations for quick and easy expert installation.


How to use your onboard RV generator

Whether it’s remote-start controls or installation-friendly automatic start systems, Onan onboard RV generators are powerful and easy to use.

One of the greatest conveniences of having an onboard generator is the ability to start it with the push of a button.

Your onboard RV generator can be started and stopped from the generator control panel or an optional remote control panel inside your RV. Here are a few things to keep in mind:

  • Before starting the generator, turn off anything requiring a large electrical load, like AC units.
  • Press and hold the start button on the control panel.
  • Allow your generator to warm up for a few minutes before turning on appliances. Turn off air conditioners and large electrical loads and allow the generator to run for 3-5 minutes before stopping to allow the generator to cool down.

Cummins also offers Energy Command - AGS+, an innovative remote start control system that gives you the ability to operate your generator using your phone or another device. With this easy-to-install technology, you’re able to start the generator while away from the RV, ensure that the battery is charged before quiet hours, regulate the temperature, and start or shut down the system using voice commands or your device.

Onboard RV generator maintenance

All generators require periodic maintenance for dependable performance. Maintenance intervals are based on hours of running time. If your generator does not come equipped with an hour meter, install one to keep track of the hours your generator runs.

Your generator handbook is a great reference for everything you need to know from a maintenance perspective. You’ll want to consult your Operator’s Manual for procedures and maintenance intervals specific to your model.

Along with keeping your generator clean and periodically inspecting it for damage, here are a few other helpful tips:

  • Turn off all appliances in cold weather before starting your generator.
  • Follow a maintenance schedule based on a running hour meter.
  • Regularly check the exhaust system for damage.
  • Periodically check the air filter and keep it clean.
  • Exercise your generator regularly.
  • Follow the safety precautions listed in your manual.
  • Change the fuel filter on a regular maintenance schedule.
  • Do not run the generator for long periods without using it to power appliances.
  • Do not attempt to adjust the carburetor, governor, choke, etc., yourself.
  • Do not run your generator set with the door panel open.

Cummins Onan onboard RV generators are supported by the industry’s largest service network in the U.S. and Canada, so you are never far from expert service.


Is an onboard RV generator right for you?

While there are many critical points to consider when choosing the type of generator best equipped to suit your needs, it boils down to a few key considerations.

Onan onboard RV generators offer unbeatable convenience. You have instant access to consistent, reliable power, and they require minimal maintenance and eliminate the need for extra equipment. Additionally, you’ll never have to haul your generator on and off your rig again, exposing it to the elements, wear and tear, and possible damage.

Choosing an onboard RV generator opens up a world of possibilities. Gone are the days of worrying about where you can and can’t travel, spending precious vacation time navigating a complicated and needy generator and waiting around a campsite for the generator to power on so you can enjoy the simple pleasures of life on the road.

Cummins RV generators offer power at the push of a button and the largest service network in the U.S. and Canada so you can go wherever, whenever.


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