Diesel Portable Generator

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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. 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.

Buyer’s Guide

  • 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.

Cummins Onan QD10000

  • 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. 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.

Frequently Asked Questions (FAQs)

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. Portability is poor. 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.

Best Portable Diesel Generators

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.

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.

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.

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.

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Also Read: Best Portable Generators [2022]. 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. 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.

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:. 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.

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. It’s better to always use the oil recommended in the generator’s manual.

Generac XD5000E Diesel Generator

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.

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.

I’ve always been a lover of Mechanics and the engineering that goes on behind it.

Naturally had a knack for fixing things and i’ve had lots of adventures that generators are second nature to me.

Factors to Consider When Shopping for the Best Portable Diesel Generator

In this buyer’s guide section, you will know about those things that you must look at before purchasing a diesel generator. So, what are those things? Take a look.

Types of Diesel Generator

First of all, it is necessary for you to decide which type of generator you want to buy. For this, you have to do some research to find out the types of diesel generators.

First, it is necessary to make sure whether you want a standby diesel generator or a portable diesel generator.

A standby generator doesn’t need your presence to turn it on during a power outage. It automatically turns on when the light goes and keeps your appliances running.

On the other hand, a portable generator needs a person to start and stop the generator manually. But since they are portable, you can easily move them from one place to another.

That is the main difference between the two. Other differences include, all the standby generators feature fully enclosed frames whereas not all the portable diesel generators come with enclosed frames, have exposed engine parts.

In order to run your sensitive appliances, it is best to go for a standby generator. They are responsible for providing consistent and clean power to your appliances, whereas not all the portable generators are responsible for doing so.

The type further extends according to the use and purpose. So, when we classify the diesel generators according to the use and purpose, we get two types. One is the industrial generator, and the other one is the domestic generator.

The industrial diesel generator is used in industries and at the construction sites and large settings. They are the big units that produce more output power.

On the other hand, a domestic diesel generator is designed to use at homes where you need less output power to run your appliances.

Also, you can classify a diesel generator on the basis of the start-up system. Some portable generators feature recoil start systems whereas some units come with and an electric start system. Also, you will find some units that feature a remote start system or come with two or all the three start systems. On the other hand, standby generators, feature automatic or manual start systems or both of them.

Moreover, you can also classify diesel generators on the basis of their cooling systems. Some diesel generators are air-cooled diesel generators whereas some units are called water-cooled diesel generators.

In the air-cooled diesel generators, the air is responsible for cooling the heated engine. A specialized air intake system cools the burning engine. On the other hand, water-cooled diesel generator uses water to cool up the heated engine with the help of an additional radiator and water pump.

Power Outage

The power output of a diesel generator is the first thing that you should look at after selecting the type. A big unit will definitely produce more power output as compared to a small or undersized diesel generator. So, it all depends on your needs and the purpose of your usage. If you are looking for a diesel generator for your RV or a small house, then a unit having low starting and running watts will be enough. But for large settings, it is necessary to buy a generator having high power output.

Run Time

If you have a fuel-efficient diesel generator then you will get more run time. Also, the tank size of the generator determines the run time. Other than this, how much load your generator is bearing also changes the run time of the generator. Your unit will offer a different run time on 25% load and different run time on 50% load.

Noise Level

In general, diesel generators are loud. They produce more sound as compared to the gasoline generators. But it doesn’t mean that every diesel generator makes noise. Some manufacturers make these generators with the enclosed frame to reduce the operational sound. Also, they use a noise-damping feature such as muffler. Moreover, the mounting system helps to reduce vibration which also results in lower noise levels.

Control Panel

It is also necessary for you to focus on the control panel of your diesel generator to make sure that it has enough power outlets to meet your needs. Some generators come with two 120V household outlets whereas some units feature four. Also, a 120V and 120/240V twist-lock outlets are must. Moreover, a 12V DC outlet is a plus.

Other things that a control panel must feature include circuit breakers, voltmeter, an hour meter, and low-fuel and oil indicators.


If you are planning to buy a diesel generator for your RV, campsites, and tailgate parties, then the unit must be portable. We have discussed the portable diesel generators in the diesel generator types, but here you should keep in mind the following things.

First of all, make sure that the wheels available are long-lasting. The size of the wheels creates problems when you pull or push your generator on a rough surface. Small tires may create problems, but a unit with big tires will not. If your unit is small or medium-sized, then small tires may be suitable, but for bigger units, big tires are a must.

Other than this, make sure that the handle or handles are ergonomically designed so that you can pull, push, or lift your generator easily and comfortably.

Safety Features

Your diesel generator must have some safety features. The safety features include low oil and fuel indicators, overheat protection, and overload protection. Also, your unit must have a safety feature to prevent short-circuiting.

Moreover, you can also go for diesel inverter generators that feature less than 5% of total harmonic distortion. This THD rating is ideal for sensitive electronics as it ensures a clean power supply.


Price is another factor that everyone should consider. If you are looking for a full-featured model, then it will be expensive, but the low-priced models come with fewer features. So, it all depends on your budget to either go for an expensive unit or a lowly-priced unit. But the most important thing is to purchase a unit that meets your power needs, no matter how much expensive it is.


Advantages of Portable Diesel Generators

If you always buy gasoline-powered or dual fuel generators that feature gasoline and propane, then you must go for them. But if you want to buy a fuel-efficient unit, then a diesel generator is the ideal choice. Even though these generators make more noise, have a shorter shelf life, and sometimes may not be easily available; these units use less fuel to provide the maximum output power. They are fuel-efficient and most of the users love to use fuel-efficient generators. Another advantage of using diesel to power your generator is that it is the least flammable fuel source. Also, diesel generators require less maintenance and are more durable as compared to gasoline generators. Also, diesel is easy to store.

Disadvantages of Portable Diesel Generators

Many people ask this question, and its answer is that it all depends on your generator model. It is recommended to go through the user manual of your generator to know which type of oil is ideal for your unit.

But if you have lost a user manual and have no idea about the oil type, then it is recommended to consider the air temperature. For high air temperatures, it is best to use more viscous oil and for lower air temperatures, use the less viscous one.

Best Portable Generators [2022]

Another advantage of using diesel generators is that they require less maintenance. They are different from the standard generators that need frequent maintenance. But it doesn’t mean that diesel generators don’t need oil changes. You must change the oil every 200 to 300 hours. Also, you can check the color and viscosity of the oil to determine the time of oil change.