Can you Refuel a Portable Generator while it’s Running?

Refueling Portable Generator while Running

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Maybe you forgot to refuel your generator before starting it, and as you settle down in your RV, the thought arrives.

I don’t have sufficient fuel in my generator to last me the evening.

Refueling the generator at this stage seems like a daunting task, as you have to turn off all the appliances, including the generator itself.

An easy way to get around this hustle would be to fill gas into your generator while in operation.

But, can you refuel a portable generator while it’s running?

You should never add gas or diesel to a running generator or when the unit is hot. Gasoline is highly flammable, which can cause an uncontrollable fire or, worse, an explosion if it comes in contact with the hot engine or exhaust. To refuel a portable generator safely, you need to turn off the motor and let it cool down to avoid fire hazards.

Though adding gas to a running generator is not advisable there are ways to extend the runtime of a generator.

In this post, we’ll talk about the safest way to add gas to a portable generator while also looking at ways to extend the run time.

Before that, let’s talk about the dangers associated with refueling a generator while it’s running.

What are the Dangers of Refueling a Running Generator?

The dangers of refueling a generator while it is running mainly come from fire. Both the vapor and the fuel itself are highly flammable and will catch fire as they come in contact with the hot engine and the exhaust system.

Because portable generators are small, all their mechanical parts live close to each other. This puts the engine and the exhaust pipe sit inches away from the fuel tank.

Depending on the size of your generator and the type of fuel you’re using, most portable generator motors and exhaust pipes will reach a temperature between 600-1000 °F. This is much higher than the autoignition temperature of gasoline (536 °F).

As you pour gas into your generator’s fuel tank from a container, the vapor from the gasoline spreads around. The increase in the vapor concentration in the air increases the risk of an explosion.

Moreover, gas from the fuel container if spilled or overfilled accidentally, will instantly catch fire. This may result in severe burns to even fatalities and may burn down your entire rig.

Fire is the #1 reason why you should avoid filling gas into your generator while it is running. A dealy of 15-20 minutes won’t kill you but a fire will.

Having a Fire Extinguisher in your RV is the cheapest and the most reliable insurance you can purchase.

How to Refuel a Portable Generator Safely?

To safely refuel a generator, first shut down the motor and let both the engine and exhaust pipe cool down. Now, using a no-spill gas can pour the fuel into your generator’s fuel tank without overfilling.

Filling gas into a generator can quickly turn into a life-threatening emergency if you don’t follow the proper procedure. Especially when you’re out in the wild where help is maybe a few hours away.

To avoid such a catastrophe, you need to follow proper safety guidelines when refueling your generator. Here we’ll talk about how you should refuel a generator that is currently running.

  1. First, turn off all the RV appliances that are being powered by the generator and remove the power cord
  2. Now use the engine off switch or turn the fuel off to kill the engine
  3. The most important step! Let the generator sit without use for at least 15-20 minutes or unit cool enough to touch the engine and exhaust pipe
  4. Using a 5-gallon gas can with a spigot, pour the gas into the fuel tank while keeping in mind not to overfill
  5. With a cloth, wipe off any spilled fuel and let it air dry for some time before starting the generator

Following the above guideline in the correct order will eliminate all sorts of hazards related to generator refueling.

How to Extend the Runtime of your Generator?

There are a few ways to extend the runtime of a portable generator safely. You can either reduce the load on it, keep a second generator, get a fuel-efficient generator, or use an extended-run gas tank.

Refueling a generator can be a time-consuming task where you need to shut down the unit, wait for it to cool down before filling gas. This is 

especially painful when you’re in a hurry or the middle of the night

However, there are ways you can run your generator for extended periods safely without having to go through the time-consuming refuel procedure.

The easiest way to extend your generator runtime on a single tank of fuel is to reduce the electrical load on the generator. For example, the Honda EU2200i on a full tank of gas will run for 3.2 hours on its rated load. Whereas the same unit will run for 8.1 hours at 25% load.

Another way many RVers avoid refueling a generator without losing power is by keeping a backup generator. Let’s say you have two Honda EU2200i units and run them one at a time. Now you have just doubled your runtime without needing to refuel.

Another option is to get a fuel-efficient generator with the largest fuel capacity. The combination of fuel efficiency and a large fuel tank will ensure you get your desired runtime without juggling with a gas can every few hours.
The last option to safely extend the runtime of your portable generator is to use an extended-run gas tank kit. All you have to do is buy an extended run fuel cap, a fuel line, and a portable fuel tank. This system uses a vacuum to pull gas from the extended gas tank into the generator but only works with Honda units, unfortunately.

Is it Bad to Run a Generator Out of Gas?

Yes, letting a generator run out of gas can be damaging for both the generator and RV appliances connected to it. If done regularly will demagnetize the coil preventing it from producing power. On the other hand, the fluctuations in voltage before it shutdown can damage electronics.

Unless you’re preparing your generator for storage, letting the unit starve out of gas regularly can damage the generator. Generators use coils to create a magnetic field which is essential to producing electricity. 

There are large voltage spikes that are caused when the unit runs out of gas. Over time, the coils lose their ability to create an adequate magnetic field reducing the production of electricity.

On the other hand, voltage fluctuations can damage the electronics that are connected to the generator. This is especially true for sensitive electronics like your cell phone, tablets, laptops, and TV.

Therefore, make sure you track your generator runtime depending on the load and avoid letting your generator run out of gas.


Refueling a generator while running is risky for both you, your family, and your RV. It can cause an uncontrollable fire that will be hard to deal with when out in the wild.

To fill gas into your generator, you need to follow the proper safety procedures. Moreover, there are various ways you can extend your generator’s runtime without the need to refuel.