Gas, Propane, or Diesel? Fueling Your RV Generator

Gas, Propane, or Diesel? Fueling Your RV Generator

One of the key appeals of RVing is the freedom it offers – the ability to park your home-on-wheels in breathtaking locations, far from the constraints of traditional hookups. While solar power has become increasingly popular, for reliable, high-wattage power on demand, especially for running air conditioners, microwaves, or charging systems quickly, an RV generator remains an indispensable piece of equipment for many travelers.

But once you decide you need a generator, a fundamental question arises: what fuel source is best? The three primary options are gasoline, propane (LP gas), and diesel. Each has its own set of advantages and disadvantages, influencing everything from the initial cost and fuel availability to efficiency, maintenance, and environmental impact. Understanding these differences is crucial for choosing the right generator for your RVing style.

Let’s break down each option.

Gasoline Generators: The Common Standard

Gasoline generators are perhaps the most common type found in a wide variety of RVs, from smaller Class C motorhomes to many Class A units and even some larger travel trailers designed for dry camping. Their prevalence is largely due to the ubiquity of gasoline and the fact that in most motorized RVs, the generator draws fuel directly from the vehicle’s main gasoline tank.

Pros:

1. Widespread Availability: Gasoline stations are everywhere, making refueling incredibly easy. You’re rarely far from a fuel source.
2. Convenient Fuel Source: For motorized RVs, the generator is typically plumbed directly into the main vehicle fuel tank. This eliminates the need for separate fuel storage beyond the primary tank.
3. Lower Upfront Cost: Generally, gasoline generators tend to have a lower purchase price compared to similarly sized propane or diesel models.
4. Good Power Output: Gasoline engines are capable of producing significant wattage relative to their size and weight.

Cons:

1. Flammability & Storage: Gasoline is highly volatile. While onboard tanks are designed for safety, carrying extra gasoline in jerry cans requires careful handling and secure storage due to the risk of fire and fumes.
2. Fuel Degradation: Gasoline can degrade over time, especially when stored for long periods without stabilizers. This can gum up carburetors and fuel lines, leading to starting problems and maintenance issues.
3. Efficiency: Gasoline generators are generally less fuel-efficient than diesel models, meaning they burn through fuel faster for the same power output.
4. Noise and Emissions: While modern generators are much quieter than older models, gasoline generators can still be relatively noisy, especially under heavy load. Their exhaust fumes are also a consideration.
5. Tank Level Limitation: Generators plumbed into the main fuel tank are usually designed to shut off automatically when the tank reaches a certain low level (often around 1/4 full). This prevents you from running the main vehicle tank dry but means you can’t use the last quarter of your fuel for the generator.

Best Suited For: Motorized RVs (Class A, B, C) where the main vehicle fuel is gasoline. RVers who value convenience and widespread fuel availability, and who plan to use the generator regularly enough to avoid long-term fuel storage issues.

Propane (LP Gas) Generators: The Clean Option

Propane generators, which run on liquid petroleum gas (LPG), are a popular choice, particularly for towable RVs (travel trailers, fifth wheels) and some motorhomes that already have significant onboard propane storage for appliances like refrigerators, heaters, and stoves.

Pros:

1. Clean Burning: Propane is a much cleaner-burning fuel than gasoline or diesel. This results in less carbon buildup in the engine, less noticeable exhaust smell and fumes, and potentially lower maintenance requirements over time.
2. Stable Fuel: Propane does not degrade over time like gasoline. You can store it indefinitely without worrying about it causing engine problems due to staleness.
3. Convenient Storage (if you already use LP): If your RV uses propane for other appliances, you likely already have one or more sizable propane tanks onboard. The generator simply taps into this existing supply, eliminating the need for separate fuel storage for the generator.
4. Quieter Operation: Propane generators are often designed to be quieter than comparable gasoline or diesel models.
5. Environmentally Friendlier: Propane produces fewer emissions compared to gasoline or diesel.

Cons:

1. Fuel Efficiency: Propane generators are generally less fuel-efficient than both gasoline and diesel generators. This means you’ll consume more propane to generate the same amount of electricity, potentially leading to more frequent refueling stops.
2. Fuel Availability: While available in many places (campgrounds, RV dealerships, some gas stations, dedicated propane dealers), propane refueling is not as universally available as gasoline. You may need adapters or specific facilities.
3. Lower Output (Sometimes): Some propane generators may have a slightly lower power output compared to equally sized gasoline or diesel units, though this varies by model.
4. Fuel Cost: The cost of propane per gallon can fluctuate significantly and may be higher than gasoline or diesel in many areas.
5. Tank Level Limitation: Like gasoline, the generator taps into your existing propane supply. If you run low on propane, it affects not just the generator but also your stove, fridge, and heater.

Best Suited For: Towable RVs and motorhomes that have ample onboard propane storage. RVers who prioritize clean operation, quietness, and long-term fuel storage stability, and who are comfortable managing their overall propane supply.

Diesel Generators: The Powerhouse

Diesel generators are most commonly found in larger, high-end Class A diesel pusher motorhomes and some very large fifth wheels designed for extended boondocking. These generators are built for heavy-duty use and efficiency.

Pros:

1. Exceptional Fuel Efficiency: Diesel generators are the most fuel-efficient option. They provide the longest run time per gallon of fuel, making them ideal for extended boondocking.
2. High Power Output: Diesel generators are often larger and more powerful, capable of running multiple high-draw appliances simultaneously.
3. Reliability & Longevity: Diesel engines are known for their durability and long lifespan, often requiring less frequent maintenance (though more costly when needed) than gasoline engines.
4. Fuel Safety: Diesel fuel is less volatile and less flammable than gasoline, making it safer to store.
5. Single Fuel Source: Like gasoline generators in motorhomes, diesel generators draw fuel from the vehicle’s main diesel tank, simplifying refueling.
6. Better High-Altitude Performance: Diesel engines are generally less affected by altitude than gasoline engines.

Cons:

1. Highest Upfront Cost: Diesel generators are significantly more expensive to purchase than comparable gasoline or propane models.
2. Noise and Vibrations: Diesel engines are typically the loudest and can produce more noticeable vibrations than gasoline or propane generators.
3. Maintenance Costs: While less frequent, maintenance for diesel engines can be more complex and expensive.
4. Cold Weather Issues: Diesel fuel can "gel" in very cold temperatures, requiring anti-gelling additives or engine block heaters to ensure reliable starting.
5. Exhaust Smell and Soot: Diesel exhaust has a distinct, strong smell and can produce soot, especially on older or poorly maintained units.
6. Tank Level Limitation: Similar to gasoline, diesel generators usually shut off when the main fuel tank is at 1/4 capacity.

Best Suited For: Large Class A diesel pusher motorhomes and large, heavy-duty fifth wheels. RVers who require significant power output, prioritize fuel efficiency for long boondocking stays, and have the budget for the higher initial cost and potentially higher maintenance costs.

Which Fuel is Right for You?

The choice of generator fuel type is often dictated by the type of RV you own, as many onboard generators are pre-installed and designed to use the same fuel as the main vehicle engine or readily available onboard fuel source (like propane).

However, if you have a choice (perhaps installing a new generator in a rig that didn’t have one, or choosing between different models offered in a new RV), consider these factors:

• Your RV Type: Motorhomes (gas or diesel) typically have onboard generators tied to the main tank. Towables often have propane or separate gasoline generators.
• How You RV: Frequent boondockers needing long run times might favor diesel or manage propane/gasoline fuel storage carefully. Weekend warriors might find gasoline or propane more than adequate.
• Budget: Diesel generators are the most expensive upfront.
• Maintenance Tolerance: Gasoline requires attention to fuel freshness; diesel maintenance can be complex. Propane is relatively low maintenance for the fuel system itself.
• Noise Sensitivity: Propane generators are often the quietest, while diesel can be the loudest.
• Power Needs: Larger rigs with multiple ACs often benefit from the higher output of diesel or large gasoline generators.

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FAQs: Your RV Generator Fuel Questions Answered

Q: Can I convert my generator to use a different fuel type?
A: Yes, conversion kits exist, especially for converting gasoline generators to run on propane. However, this is often a complex and expensive process, and it may void the generator’s warranty. It’s generally best to choose a generator designed for the fuel you intend to use.

Q: How long will my generator run on a tank of fuel?
A: This varies greatly depending on the generator’s size (kilowatt output), the load it’s running (how much electricity you’re using), and the fuel type. A large generator running an air conditioner will consume fuel much faster than a smaller generator just charging batteries. Check your generator’s manual for estimated run times at various load levels. Propane generally has the shortest run time per gallon, while diesel has the longest.

Q: Do I need to run my generator regularly if I don’t use it often?
A: Yes, absolutely. Generators, especially gasoline ones, need to be run periodically under a load (e.g., running the AC or microwave) to keep the carburetor clean, lubricate seals, and ensure it’s ready when you need it. Follow the manufacturer’s recommendations, but monthly is a good general guideline.

Q: Is one fuel type better for high altitudes?
A: Diesel engines are generally less affected by altitude than gasoline or propane engines, which can lose power as oxygen becomes thinner.

Q: What about portable generators? Do they use the same fuels?
A: Most portable RV generators are gasoline or dual-fuel (gasoline and propane). They are separate units you carry and connect externally, offering flexibility but requiring manual refueling from jerry cans or separate propane tanks.

Q: Is the "minimum fuel level" for tank-integrated generators adjustable?
A: No, this is a built-in safety feature designed by the RV or generator manufacturer to prevent you from being stranded. It cannot be easily disabled or adjusted.

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Conclusion

Choosing or understanding your RV generator’s fuel source is a key part of mastering off-grid power. Gasoline offers convenience and low initial cost but requires attention to fuel freshness and storage safety. Propane provides a clean-burning, stable, and often quieter option that integrates well with existing LP systems but is less fuel-efficient. Diesel is the powerhouse choice for efficiency and longevity, primarily found in larger rigs, but comes with the highest upfront cost and different maintenance considerations.

Ultimately, the "best" fuel is the one that aligns with your RV type, your travel habits, power needs, and budget. By understanding the pros and cons of gas, propane, and diesel, you can ensure your RV generator is a reliable source of power, enabling you to enjoy the freedom and adventure of RVing wherever the road takes you.