Generator Fuel Consumption Guide: How Long Generators run on Gas/Propane/Diesel?

To keep all your appliances running at home or recharge your electronics at the campsite, a generator is a great choice. It is useful in many aspects of our life. But, sometimes so happens that you run out of fuel in between a blackout and have no fuel stored. Also, if your generator runs on gasoline, then all the gas at the gas station is sold out. This is how your generators are limited.

Generators have fuel tanks that will determine the runtime of it, and the fuel tank limits the usability of a generator. Most of the generators will provide a runtime of 8 to 10 hours. That is good and can get you through the night.

But, if the blackout continues for days, then you might want to store the fuel to get you through the days. In this article, we have discussed how much runtime different sizes of generator will provide for a certain volume of fuel. You can use this data to calculate how much fuel you should have handy to keep your generator running for an extended period.

How long can the generator run Continuously?

Generators have mechanical parts inside them accompanied by the engine, and it is the same as every other engine in an automobile. It can’t run continuously for longer periods. The portable generators are designed to power the appliances during power outages, not to use as a permanent replacement for your electrical utilities.

If it runs for longer, without a break, then the mechanical parts and engine inside the generator will fail. For how long a generator can run before it needs to cool down depends on many factors. It depends on how much power is used of the total capacity, fuel type, and fuel tank size.

Let’s first talk about the tank size. A portable generator can have a tank ranging from few gallons to more than 10 gallons. The larger the tank, the more the runtime. The runtime will be affected by the wattage utilized, but a general estimate tells that a generator can run for one and half hours to three hours on a gallon of fuel.

This means that if the load connected is supposed to be 25%, then a generator can run for three hours and sometimes even more. But when the load increases, the runtime will decrease. You might get one and a half hours of runtime if the load connected is 100%.

Now, let’s take an example. Suppose you have a generator with a fuel capacity of 6 gallons. If the connected load to the generator is 50%, then it will be a good estimate if we say that the generator offers two hours of runtime per gallon.

So, considering fuel tank size, it will run for 12 hours continuously. But, if the load connected is 100%, then you might get only a few hours of runtime from it before it needs to cool down. Once it cools down, you can refuel it, reoil it then it is ready for another session.

Another parameter that varies the runtime is the fuel used instead of gasoline; if propane is used as fuel, then you will get a few hours more runtime as propane is more efficient than gasoline. This means it will be used in less amount compared to gasoline.

A generator can have a varying runtime based on the model and its efficiency, and it depends on the fuel and the tank size. Some generators can offer a runtime of 2 hours, and there are those which can run continuously for 24-hours.

The runtime of a generator on a 1 gallon of gasoline

Gasoline is the most preferred fuel for most homeowners due to its easy availability, but they are a bit pricey. Gasoline generates power more efficiently than any other fuel. It is highly flammable, so it isn’t a good idea to store them in large volumes; it may result in fire and explosion.

Now, coming to the point, a generator’s runtime depends on the tank’s size and the load connected. If a 5000-watt generator has 18 gallons of fuel in the tank, then it will run for 24 hours. That fuel tank size for any portable generator is unrealistic and impractical.

But it can help users to determine the runtime of that 5000-watt generator on 1 gallon of fuel. Assuming that a generator is an inverter generator, it can last for 7 to 10 hours. You can expect that it will give a runtime of no less than 5 hours on a single gallon of gasoline.

The runtime of a generator on 5 gallons of gasoline

As we keep reminding you that the runtime is a variable and many factors can affect it, the major one is the number of appliances plugged in the generator. There are generators in the market which have to offer an impeccable runtime and power output.

Generally, 5 gallons of gas used for a 5000-watt generator will give a runtime of 8 hours. But it highly depends on the power you are drawing from the generator. If the load connected is low to moderate, then you might be able to get a runtime of more than 12 hours and sometimes even 24 hours from that generator.

But, even if the generator is running at its full capacity, then you shouldn’t expect a runtime of fewer than 8 hours.

For how long will the power be available when propane is used?

The propane is becoming quite popular nowadays and the reason being its longer shelf life and very efficient operation. It won’t go bad for as long as 12 years, and that too without any stabilizers. Propane is available in the tank of various sizes. For portable use, they are available in smaller tanks like 25-lbs tanks, while for standby power needs, people generally install a larger tank at the house.

The general size of a generator to have at home is 5 kW, 7 kW, 12 kW. They can either run a few heavy-duty appliances or can even power all the appliances of the house if the house is small. On 100 gallons of a propane tank, a 7kW generator offers the runtime of 66 hours, while for the same, a 12 kW generator will run for 36 hours.

If the generator is of 5000 kW size and the tank is of 5000 gallons, yes, people install that much larger tank as the propane doesn’t go bad. The runtime will be 920 hours. If used on a 24lbs propane tank, then this 5000 kW generator provides a runtime of one and half hours.

If we talk about the smaller generator, a 3000 kW generator, then a 5000 gallons propane tank provides a runtime of 1200 hours. Whereas, for portable use, on a 25 lbs. propane tank, the runtime will be 50 to 60 minutes.

How long does the diesel generator run?

The main purpose of a diesel generator is to be used as a backup where a large quantity of power is required, whether it is a large home, hospital, or any other commercial building. They use diesel generators as a power backup.

Along with the generator, the owner keeps the large quantity of diesel at hand so it can be quickly refueled without any hassle. The runtime of the generator will depend on the load it powers and the total fuel you have. So, what we will do is provide the runtime of a diesel generator at various loads connected for gallons of diesel used per hour. From that, you can easily calculate how long your generator will run based on the fuel you have at hand.

Suppose a 20kW generator is running at a quarter of its total load capacity, then it will consume 0.6 gallons of fuel per hour. When the load increases to half, the fuel consumption will be 0.9 gallons per hour. Now, as the generator load increases to 3/4 and up to the full capacity, the diesel used per hour is 1.3 gallons and 1.6 gallons, respectively.

Conclusion

As we conclude our discussion, we hope that you got all the necessary information regarding the generator fuel consumption and its runtime. Generators are a great and very useful tool, especially in a long blackout. So, When one of those longer blackouts hits, with this information, you will be prepared with enough fuel to get through it.

Again, the runtime of the generator will depend on the fuel tank size, the appliances connected and the type of fuel used. So, you can now determine how much fuel you will need to store so that you can run your generator for a predetermined time. Also, to avoid all this hiccup for generator runtime, you can use dual fuel generator so that you can use any fuel as per your convenience rather than being dependent on your fuel available at hand.

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