How To Use and Maintain an Onboard RV Generator

Contributor

Tucker Ballister

Favorite Trip

5 Months Solo on the Road

Home Base

Hendersonville, NC

Favorite RV

2008 Fleetwood Bounder

About Contributor

Tucker Ballister is our Content Strategist. He’s a lover of the open road and the proud owner of a 2021 Sunlite Classic travel trailer (his 3rd RV to date). Check out more of his RV adventures, gear reviews, and outdoor advice at thebackpackguide.com.

You’ll find onboard – also known as “built-in” or “permanent mount” – RV generators on many motorhomes and some toy haulers. A generator allows you to enjoy more comfortable boondocking because you essentially have a built-in way to generate AC power. 

Instead of relying solely on your battery’s storage capacity, you can fire up your generator to deliver safe, efficient power to your appliances while recharging your batteries. If your RV came equipped with an onboard generator, let’s cover the basics of how to use and maintain it properly: 

How To Use an Onboard RV Generator

Man pushing start button on onboard rv generator
Photo by Camping World

For starters, all RV owners should read their owner’s manual for the manufacturer’s recommended operating procedures. For example, air-cooled generators must have an access door in place for proper cooling. Your owner’s manual is your best resource when learning how to use your RV’s onboard generator. 

Most onboard RV generators can be started by a button on the unit or a secondary button on a remote control panel inside the RV. Before you start your generator, check that all appliances are powered down – especially large appliances like your air conditioner, microwave, and electric fireplace (if equipped).

Depending on your manufacturer’s recommendation, you may need to prime the generator’s fuel system by pressing and holding the stop button for the recommended interval. To start your gas generator, press and hold the button. Gas RV generators will immediately crank, but you may need to hold the button for 5-10 seconds until you hear the engine turn over. 

Diesel generators are designed to complete a series of internal checks before starting. You’ll need to continue to hold the button until it starts. On cold mornings, your generator could take up to 30 seconds to start.

Allow your generator to run for at least two minutes before placing it under load (i.e. turning on large appliances). The generator will then continue to run until you use the switch to shut it down. When ready to shut it down, start by turning off all appliances. Allow it to run without a load for 3-5 minutes. Then hit the stop button to power your generator down.

Tips for Smart Generator Use

cummins onan generator in tiffin allegro breeze
Photo by Camping World

Built-in RV generators are expensive pieces of equipment that are much easier to maintain than to replace. Here are a few tips for safe, smart generator use: 

  • Run your generator regularly. Most manufacturers recommend running your generator at least once a month. To exercise your generator:
    • Start it and let it run without load for two minutes. 
    • Run it at 50% load for a minimum of two hours, either all at once or in two, hour-long sessions.
    • Turn off all appliances and let it run without load for 3-5 minutes. 
    • Power it off. 
  • Avoid running it for long periods without a load.
  • Ensure the generator’s exhaust pipe extends at least one inch beyond the RV’s exterior and is at least six inches away from any openings. Your generator’s air intake and discharge must be free from any blockages.
  • Check that the access door is in place. This must be ensured when operating for cooling purposes.
  • Know the effects of altitude. Generators are typically rated at 500 feet of elevation. Power will decrease approximately 3.5% for every 1,000 feet of elevation increased beyond that initial 500 feet. Take altitude into account when calculating the maximum load you can place on your generator to avoid overloading it.
  • Check your CO detector. Verify that the batteries are good and the detector is installed according to their listing. Use the manufacturer’s recommended protocol to test the unit and ensure it works properly.

How To Maintain an Onboard RV Generator

motorhome on lift in maintenance garage
Photo by Camping World

Again, your owner’s manual will be your best resource. The manufacturer will provide service intervals and, in some cases, recommended service procedures for the many items mentioned below – and possibly others. That said, here are a couple of general recommendations:

  • Cummins Onan generators have a pretty easy requirement: the first oil change is 50 hours for diesel and every 150 hours (or 250 hours for larger units) or once yearly thereafter.
  • Gasoline models require oil changes every 150 hours or once per year, whichever comes first.

In addition to regular oil changes, here are a few other tips for maintaining your onboard RV generator: 

Keep the Generator’s Compartment Clean 

The less dust and debris you allow to accumulate in the generator’s compartment, the less its air filter will need to work to ensure clean air flow and keep the engine from overheating – not to mention keeping potentially damaging debris from getting into the engine and potentially damaging internal components.

Check and Clean the Filters Regularly 

Most generators are equipped with an air filter and a fuel filter. The fuel filter must be replaced according to the manufacturer’s recommended interval. The air filter must be cleaned regularly by tapping it on a flat surface. Avoid using water or compressed air to clean a generator’s air filter.

Regularly Inspect the Exhaust System and Fuel Lines 

Look carefully for damage and leaks. Use your owner’s manual to understand what to look for in these checks. 


Proper generator maintenance is vital to keeping it running efficiently to deliver safe power to your RV. If you need your generator serviced, contact your local Camping World Service Center to schedule an appointment.

What questions do you have about using and maintaining an onboard RV generator? Let us know in the comments below.

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