Best Portable Diesel Generator

A portable diesel generator can serve as a reliable solution for a temporary home backup and for use on remote sites. When looking to choose between a gasoline, propane, or diesel portable generator, you’ll come across a variety of positives & negatives for each type.

As for a diesel generator, its main advantage is — it provides superior fuel efficiency, translating to longer runtimes and lower fuel expenses overall.  Precisely, this kind of generators has been found to be up to 20 percent more efficient compared with the other types of generator.

And this better fuel efficiency of portable diesel generators comes down to one thing: Diesel’s energy density is much higher, which yields more power per unit. In other words, if you rely on a portable generator to supply power to different power-hungry tools & appliances often, in the long run, a diesel generator will save you a lot of money in fuel costs.

In this post, we take a look at some of the best portable diesel generators on the market.

Best Portable Diesel Generators

Generac XD5000E Diesel Generator [eBAY]

The Generac XD5000E diesel portable generator runs on a Yanmar LW Series 435cc air-cooled direct injection, industrial-grade diesel engine, which pumps out 5,500 peak watts & 5,000 running watts.

Generally, diesel generators aren’t the same as inverters. This Generac model isn’t a portable generator either, but it produces cleaner power compared with a lot of the other diesel generators.

This is as a result of its True Power Technology that offers less than 5 per cent THD (total harmonic distortion). That implies the power is not only clean but also smooth, enabling you to even make use of this machine for powering some of your sensitive electronics.

It’s a very durable model, which has a tough and fully-welded 1-1/4″ steel frame. Also, the frame is remarkably sturdy, designed for making lifting for transport easier.

The set is pretty heavy at about 250 pounds, but the frame design has handles, making it much easier to lift. Also, you can purchase a wheel kit separately to ensure it can be transported even easier. If you seek a long runtime, The Generac XD5000E could be the best portable diesel generator for you.

With its massive 12-gallon fuel tank, you can use the generator for slightly more than 32 hours on a 50% load.

The generator is easy to start, and you can either choose between a recoil pull start or an easy push-button electric start. Unfortunately, neither is the battery included for the electric start nor is a remote start option offered.

In the control panel, we’ve an hour meter, a 23-amp main circuit breaker, one 120/240V selector switch, two 20-amp push-button circuit breakers, one 30-amp push-button circuit breaker, four 120-volt 20-amp outlets as well as two 120-volt TwistLock outlets.

There’s an automatic shutdown option if the oil pressure becomes too low, and a compression release lever is available, ensuring the unit is easier to start in cold weather.

The machine’s drawback is, it isn’t the most affordable option considering the output it provides as a gasoline-powered version in the 5000W range may only come with half or even a quarter of this Generac XD5000E’s price. This higher price tag will offer you a more efficient unit that has lower maintenance costs & requirements.

These are things an average buyer wants.


  • Sturdy steel frame
  • Affordable compared to the competition
  • Portable design
  • Large fuel tank & super long runtime
  • Hour meter for monitoring maintenance schedule
  • 2-year limited warranty
  • EPA/CARB compliant
  • Cleaner power with less than 5 per cent THD


  • Requires you to buy a battery separately

Cummins Onan QD10000 [EBAY]

The Cummins Onan QD10000 Diesel Generator specifically designed for residential vehicles (RVs). It’s a powerful diesel generator, which can handle running 3 AC units simultaneously. It delivers 10000W surge power and 8000W running power. This makes it also a suitable option for use as a home standby generator.

Because there’s no fuel tank inside the casing, you’ll need to connect a separate fuel tank so you can get the engine running. Please, note that it makes use of up 0.43 gallons of diesel every hour when running a 50 per cent load.

Some of the highlights of the Cummins Onan unit are, it’s technologically advanced with a computer-controlled variable speed, has a microprocessor for self-analyzing for any issues & troubleshoot, and gives pure sine wave output. With these features, you’ve in your possession a low maintenance & high-performance diesel generator.

The maker has included many noise-cancelling elements, like a casing, muffler, as well as an enclosed cooling system that takes the rated noise level down to 70dB. This enables the machine to meet the US National Park sound requirements.

Also, the portable diesel generator is also fully compliant with EPA and CARB regulations, allowing you to power your RV in any state in the United States.

Though an electrical start is the standard option in diesel generators, the Quiet Series RV QD10000 takes it a step further by including a remote start. In the package, you’ll find a key fob, allowing you to start the engine from a distance. This feature is useful when you’re on the other side of your RV.

The major downside of this model is, its portability leaves much to be desired as it weighs more than 750 pounds. To make matters worse, it doesn’t have any tires or pulling handles, so this isn’t a generator designed for mobile use.

This unit is a reliable off-grid power source, ideal for users planning to embark on an epic road trip in their RV or looking for an emergency standby generator for their home. It offers high output and low THD. These make it a smarter option for connecting sensitive devices.


  • Remote start
  • High pure sine wave output


  • Portability is poor
  • Expensive

Buyer’s Guide

Advantages of Portable Diesel Generators

Fuel Efficiency

Why do you think nearly all infrastructural and high-power job site projects primarily make use of diesel generators? The answer is simple: Such generators are relatively highly efficient, and that translates to cost-effectiveness. Further, portable diesel generators are much more efficient in comparison with gas generators due to the ignition type they feature.

Though gas-powered generators utilize a spark plug for igniting a mixture of air & fuel, their diesel-engine counterparts subject air to high compression, causing high temperatures in the engine. Once diesel gets injected, it brings about powerful explosions, resulting in less fuel wastage. Thus, a diesel-powered generator will operate longer with the same amount of fuel.

Easier Maintenance

Since diesel engines rely on combustion-ignition, they don’t make use of a carburetor & spark plug. As a result of this, accessing the engine for maintenance and general lubrication is a lot easier. Additionally, that the carburetor & spark plug aren’t available basically means you’ve 2 fewer components to maintain.

Longer Shelf Life

All things being equal, portable diesel generators are often longer-last than their gasoline counterparts since gas burns hotter in comparison with diesel, resulting in reduced life span in gas-powered units.

Another factor that’s often considered trivial is that diesel generators self-lubricate, which mitigates against wear and tear.

Longer Lifespan

When it comes to lifespan, portable diesel generators have built a solid reputation for their ruggedness. When proper maintenance is provided, experts believe a diesel generator can last longer than a similar size gas generator by as much as three times.

This implies that though the initial outlay for diesel power units is typically comparatively higher, in the long run, the generators are practically more affordable.

Also Read: Best Portable Generators [2022]

Disadvantages of Portable Diesel Generators

Repairs and Servicing Could Be Costly

Due to the large & heavy components used in making diesel engines, the cost of repairs can be high. But they compensate for that with their infrequent maintenance needs.

High Noise Levels

As you might have noticed, diesel generators are known for their high noise levels. Though contemporary models come with superior features for handling this issue, they still operate at higher decibels in comparison with models of similar sizes.

Factors to Consider When Shopping for the Best Portable Diesel Generator

Apart from the price of a portable diesel generator, other things to pay attention to are power output, noise level, runtime, and portability. Let’s look at each of them in detail:

Power Output

Based on what you intend using the diesel generator for, it’s to be powerful enough to carry the appliances you plan running on it.

Noise Level

Go through the generator’s spec sheet to know the dBA level. For long, diesel generators haven’t been the best performers as regards noise level, but nearly all the recent offerings now feature top-quality mufflers & silencers, which make them quiet. Despite that, if you require a quieter model, we recommend you check the best quiet generators.


This term has to do with how long in hours a portable diesel generator will be able to run when it’s on a full tank at 25 per cent, 50 per cent, or 100 per cent load. Generally, runtime depends on the tank size. Hence, large tanks provide longer runtimes. However, it’s also affected by the load since the higher the load on the generator, the more fuel gets consumed.


It’s essential to consider how easy it’s to move your diesel generator. Depending on the generator’s weight, consider whether it comes with a wheel kit or sturdy grab handles. In the same vein, its dimensions are also important especially if you prefer a model, which you can carry on a truck.

Frequently Asked Questions (FAQs)

Which oil is recommended for use for a diesel generator?

It’s better to always use the oil recommended in the generator’s manual. For instance, the recommended oil type for the Generac 6864 is SAE 10W-30. That oil may be a safe bet for every diesel generator but consider checking the manual to be sure. The correct oil type for a lot of diesel generators should consider the current ambient air temperature.

For colder temperatures, you can make use of an oil that has a lower viscosity such as 5W-20. But for really hot temperatures, you can go for an oil that has a higher viscosity such as SAE 40. Irrespective of the specific type of oil you choose, it’s essential to follow all the oil-related maintenance procedure as stated in the user’s manual for the diesel generator. Generally, this comprises things like checking the oil in the generator regularly, usually before every start.

After so many hours of use, you must also change the oil completely. The generators above have an indicator on the control panel, which notifies you when a change of oil is due. If you fail to follow the maintenance instructions in the generator’s manual, the generator won’t serve you for as long as it should, and that could even void its warranty.

What’s the lifespan of a diesel-powered generator?

No exact answer can be given for how long a portable diesel-powered generator lasts because a lot of several factors are responsible for that, such as proper loading, regular & timely maintenance, etc. But if a gasoline generator can last 10000 hours, all things being equal, diesel generator of the same size can definitely last up to 30000 hours.


To conclude today’s post on the best portable diesel generator, let’s do a recap of all what we’ve discussed so far. First, we told you that the best diesel-powered generators are the Generac XD5000E and the Cummins Onan QD10000.

Then, we reviewed the features of these models, outlining their pros and cons. Taking a look at some of the best advantages of portable diesel generators, we stated that fuel efficiency, easier maintenance, longer shelf life, and a longer lifespan are some of these advantages.

As for their disadvantages, these include high cost of repairs & servicing and high noise levels of the units. Lastly, when shopping for the best portable diesel generators, important things to take into account are power output, noise level, runtime, and portability.

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