How Long Can a Dual Fuel Generator Run on Propane?

A dual-fuel generator can be a lifesaver in power outages, especially if you use propane. 

Many propane generators will kick in automatically to supply backup power to your electronics, appliances, or even your entire home, depending on the generator’s power output capacity. 

A standard dual fuel generator can last anywhere from six to twelve hours on propane. But the run time depends on multiple factors, including the wattage demand and how much propane you have. 

This guide explains the steps for calculating how much propane you need and its many benefits as a fuel source. 

Let’s begin! 

How to Calculate How Much Propane Is Needed to Run a Dual-Fuel Generator

Calculating the amount of propane your dual fuel generator uses per hour helps determine how much liquefied petroleum gas (LPG) you need in stock. 

The formula is as follows: 

Total LPG (gallons)  = propane used per hour (gallons) x number of hours 

However, a few calculations are needed to find your generator’s LPG consumption rate. Follow the steps below. 

Step 1: Calculate Horsepower

First, calculate how much horsepower the generator uses. You’ll obtain the horsepower by dividing the total watts by 1,000 and multiplying the results by 2. 

Horsepower = (watts / 1000) x 2 

Let’s say you have a power demand of 4,000 watts. Your generator requires 8 horsepower. 

Step 2: Determine How Fast the Unit Burns Fuel 

Next, you’ll want to determine how fast the fuel of propane burns with your machine. 

BTU = horsepower x 10,000 

In this example, a 4,000-watt load requires fuel that produces 80,000 BTU per hour. (8 horsepower x 10,000) 

Step 3: Figure Out the Propane Consumption Rate

Now you can determine how much propane this is in gallons. 

Gallons of LPG = BTU / 92,000

Then divide the burning index by the fuel value of LPG, which is 92,000. 

In this case, the gallons of propane is equivalent to 80,000/92,000 = 0.87

As a result, your LPG consumption rate would be 0.87 gallons per hour to run a 4,000-watt load generator. 

Step 4: Putting Everything Together

You can now refer to the original formula to calculate the total amount of propane you need. 

Total propane = LPG used per hour x total number of hours 

In this example, let’s say you’d like to run your 4000-watt generator for three days (i.e., 72 hours) worth of fuel. 

0.87 gallons x 72 hours  = 62.64 gallons 

You’ll need 62.64 gallons of LPG to survive roughly three days of constant power output. 

You can convert the total propane in gallons to figure out how many 20 lb LPG tanks you’d need. A 20lb tank of propane contains 4.6 gallons when full:

62.64 gallons needed / 4.6 gallons in a tank = 13.6

Round up, and you’d need 14 20 lb LPG tanks to run your generator for three days.

Keep in mind that this is if you strictly use propane. The beauty of dual-fuel generators is that they can switch between LPG and a secondary fuel source (like petrol), making your generator run longer. 

How Efficient Are Propane Generators?

From a fuel efficiency perspective, propane generators are about twice as efficient as natural gas generators. A propane generator uses half the fuel to generate the same electricity as a natural gas-powered generator. For example, one cubic foot of LPG has 2,490 BTU, while natural gas has only 1,040 BTU per cubic foot. 

Of course, you can always pair your propane generator with other generators — such as solar power generators — to provide more output and storage capacity. Products like the EcoFlow Dual-Fuel Smart Generator pair seamlessly with the DELTA Max or DELTA Pro and solar panels

Benefits of Using Propane Generators

Propane is an excellent alternative fuel source, with several benefits over other fossil fuel types, such as petrol or diesel. 

Cleaner Fuel 

Propane burns cleaner and produces fewer emissions than petrol or diesel. It contains less carbon and produces less carbon pollution, making it more environmentally friendly than other fossil fuel options. For example, the EcoFlow Smart Generator produces 10% of the carbon monoxide as petrol options, creating fewer fumes. 

Granted, there are far more eco-friendly options, like EcoFlow Portable Solar Panels paired with a DELTA Pro Solar Generator for a clean, renewable energy source. However, alternative fuel sources like propane can be invaluable as a last line of defence for backup power. 

Longer Shelf Life

LPG fuel can last a long time without losing its burnable energy as long as you store it safely. It can last several years when stored in pressurised containers and has one of the longest shelf lives of liquid fuels. 

Other fossil fuel sources can’t last long. Petrol degrades within a few months, and diesel lasts for 18 to 24 months but requires specialised storage tanks. 

Due to the propane’s inherent longevity, you won’t need to purchase expensive stabilisers to prevent it from going bad. 

Little to No Additional Maintenance  

Petrol and diesel generators create large carbon deposits in their exhaust and engine, which requires regular cleaning to prevent residue build-up in the fuel lines and system components. 

Propane is a cleaner fuel source: going months, sometimes years, between cleanings or service dates. 

Cold temperatures also don’t negatively impact propane generators like diesel or gasoline-powered setups. Propane doesn’t freeze until it reaches -152 Celsius, so you won’t have to worry about the machine failing when the temperature drops. 

Ease of Availability 

Propane is easily accessible in many hardware stores, petrol stations, and dedicated propane suppliers. It’s also safe to transport in your vehicle, which makes it a good choice for emergencies or camping outdoors. 

How Long Can EcoFlow’s Smart Generator (Dual Fuel) Run Solely on Propane?

EcoFlow’s Smart Generator can last up to 12.5 hours of runtime on a 4-litre tank of LPG (propane). You can generate as much as 20 kWh to run appliances and fast-charge your DELTA Max or DELTA Pro portable power station in as little as 1.8 hours.

EcoFlow’s Smart Generator provides seamless additional backup power capacity for your Smart Home Ecosystem with a fuel-efficient option when your solar power runs out. 

Frequently Asked Questions

How Long Can a Generator Run on 20 lbs of Propane?

A standard 20 lbs (4.6 gallons) propane tank lasts about 5 hours. However, the actual run time depends on the wattage demand of the generator. Naturally, the run time decreases as consumption increases. 

How Long Will a 1000-gallon Propane Tank Run a Generator?

Most propane-powered generators have a maximum capacity of 1,000 gallons. At a typical rate of burning 2 to 3 gallons per hour, a 1,000-gallon propane tank can run a generator for about 200 (8.3 days) to 400 hours (16.7 days).

Final Thoughts

Knowing how much propane you need to power your dual-fuel generator helps you prepare for the worst. 

Many variables affect the run time, such as the generator’s power consumption and how efficiently it uses propane. 

Investing in a dual-fuel generator is a wise choice, whether riding out a blackout or going off-grid. Shop EcoFlow today for energy-efficient backup power solutions. 

EcoFlow is a portable power and renewable energy solutions company. Since its founding in 2017, EcoFlow has provided peace-of-mind power to customers in over 85 markets through its DELTA and RIVER product lines of portable power stations and eco-friendly accessories.


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