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How Long Can You Run a Generator Continuously? Factors & Requirements


Generators can provide you with power while you’re out camping and keep your home functioning normally during a power outage or environmental disaster. Since these tools are so important, many people wonder how long you can continuously run one. If you want an answer to this question, keep reading as we discuss several factors that can affect how long a generator can run, so you can feel more comfortable using it during the next power outage.

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How Long Will My Generator Run?


The main thing affecting how long a generator can run continuously is what fuel it uses and how large the tank is. A solar power generator can only run while there’s enough sunlight to charge it, and it’s unlikely to run through the night, especially if you also use it during the day. Other brands use gasoline, diesel, propane, or natural gas. If you are using natural gas, you can connect the unit to your home line for an unlimited fuel supply, but the other kinds will have a tank that will only hold so much fuel, and you’ll need to stop the generator to refill the tank when it’s empty. Some generators can have large tanks, but you’ll still usually need to refill them within 12 hours of starting the machine.

gasoline powered portable generator
Image Credit: canoniroff, Shutterstock

Output Requirements

The more items you have connected to your generator, the harder the motor will run, which will use up the fuel faster. High-demand items, like the refrigerator, heater, or air conditioner, can use gas quickly, while a TV or LED lighting are less fuel intensive.


The age of your generator will also affect how long it will run continuously. An older, worn-out generator will be less efficient, using more fuel, outputting less power, and requiring more shutdowns.

Motor Size

The larger the motor in a generator, the more fuel it will use, leading to more frequent refills and engine stops. Large motors usually have a large fuel tank, giving them similar runtime to a small unit, though at a higher cost.

Portable Generator CARB compliant
Image Credit: N-sky, Shutterstock


Some manufacturers design generator motors and other components better than others, producing more output while using less fuel and giving users a much longer runtime.

Engine Rest

Although you will find a few generators stating that you can use them continuously for 500 hours and natural gas provides you with an unlimited fuel supply, most experts recommend shutting down the generator after 72 hours for at least 2 hours to give the motor a rest. Pushing even the best motors beyond 72 hours can cause premature wear, reducing the generator’s lifespan.

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Other Factors to Consider

  • Connecting your generator to the natural gas line in your home can be a great solution in most cases. However, during a natural disaster, the gas is often turned off to prevent explosions, which will leave you without power.
  • If you use a gasoline power generator and store fuel to power in an emergency, you will need to add ingredients to keep it fresh because gasoline goes bad quickly. So, it might not be useful when needed.
  • A changeover regulator on a propane generator will enable you to use two or more tanks simultaneously, allowing longer run times.
  • Always let a gasoline engine cool down before refilling it, as the high temperature can ignite the fuel.

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Top-of-the-line generators with an unlimited fuel source can usually run about 3 days before you need to shut it off for a couple of hours to let it cool down. However, the vast majority of generators will run 12 hours or less before they run out of fuel and you need to shut it down, let it cool, and refill it, with most typically lasting 6 to 8 hours on average.

Featured Image Credit: Virrage Images, Shutterstock


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