Best Portable Diesel Generator

Generators are a valuable piece of equipment for anyone looking for a temporary power source. They are perfect for powering homes when there is a blackout for powering RVs, campsites, and remote job sites. While portable diesel generators may not be as popular as portable gasoline models, they are the best alternatives to gasoline generators. Diesel portable diesel generators also have several perks, including long runtime and high power output. 


The best portable diesel generator is the best option for powering power-hungry items for long hours. However, not all diesel generators in the market are reliable. Some will look good when you are buying them only to turn out to be unreliable after running them for some months. So, how can you spot the best portable diesel generator? Here is a review of the five best diesel generators, a buying guide, and answers to frequently asked questions.


  1. Generac 6864 Diesel Powered Portable Generator 


The Generac 6864 is one of the best generators in the market, and it also happens to be one of the most expensive. You should invest money in this generator because it’s capable of delivering up to 5500 watts of starting power and 5000 watts for running applications. It can last for around 32.5 hours at a 50% load with a 12 gallons fuel tank capacity. With this runtime, you can easily power a small home in case of a blackout. Or power a small RV overnight and remain with fuel for the next day.


Thanks to its easy-to-use electric starter, the Generac 6864 is also easy to start. And it comes with a power panel with four 120V 20A sockets, 120V 30A, and one 120/240V 30A twist-lock socket. You can power your sensitive appliances with this generator, thanks to its less than 6% THD level. The best part about the generator is that it comes with a 3-year warranty which means you do not have to worry about buying another one after using it for some time.


This model weighs about 252 pounds. You can move it around easily with its wheel kit. The open-frame design with handles on top and sides makes it easier for you to lift or move the generator.




  • Very easy to start and use
  • It can last for around 32.5 hours with a 12-gallon fuel tank




  • It does not come with a battery and wheel kit; you have to buy them separately.


  1. Gilette GEN-PRO GPED-65EK Diesel


The Gilette GEN-PRO GPED-65EK Diesel is a heavy-duty, portable generator that’s perfect for contractors or anyone who needs reliable power on the go. It uses clean diesel fuel to run its reliable engine and is dependable power for emergencies. When you need dependable power that can also be portable, consider the GPED-65EK.


This generator has a starting wattage of 6500 watts and a running wattage of 5000 watts of clean power. This large power output makes it ideal for powering heavy-duty items, including tools, appliances, pumps, ATVs, etc. It can last 10 hours on a 4-gallon fuel tank, which means you have the freedom to power your equipment for more extended periods without worrying about refueling. For further convenience, this model has a built-in fuel gauge that comes in handy when you want to keep an eye on the fuel level.


This generator has six total outlets: 


  • Four 15-Amp 120V outlets
  • One 30-Amp 120V outlet
  • One 50-Amp 120/240V outlet.


You can power various items with this generator without worrying about tripping.  


Its open-frame design offers an easy time when it comes to lifting this heavy-duty generator. Its handles on top and sides also come in handy when moving it around. It comes with a wheel kit provision, so you can buy the kit for additional convenience.




  •  It offers a decent runtime
  • It comes with all the necessary outlets
  • Easy to start and stop



  • It does not come with a wheel kit to improve its portability.


  1. Power Products Sigma 7000W


The Sigma by Power Products is an excellent investment for homeowners with several devices that need power. With its high capacity, this product can serve all your needs, from air conditioning systems or refrigerators in the home to an electric stovetop and water pump.


This power equipment has a power output of 7000 starting watts and 5500 running watts. It has a powerful diesel engine that makes it ideal for powering heavy-duty items. It can provide continuous power for up to 8 hours at a 50% load with its 4-gallon fuel tank capacity. the 8 hours runtime is pretty enough to power your essential appliances. However, you can extend its runtime by attaching an external fuel tank. 


This model has 4 power outlets;

  • 120-volt 30amp twist lock
  • Two 120-volt 20A
  • 120/240 volts 20A


The power outlets have twist-lock functionality that allows you to plug an RV adaptor when you intend to power an RV.


You will find the fuel gauge, low oil warning light, and voltmeter on the control panel.


Unlike other diesel generators that are noisy, this model operates at 68 decibels. This makes it ideal for emergency backup power during an outage. It will run with low noise, and you won’t have to worry about bothering your neighbors with its noise output.


This yellow power beast is heavy. However, it comes with a set of wheels and handles that allow you to move it around easily. It weighs 363 lbs.




  • Easy to start up or stop (electric starter)
  • Its a powerful yet affordable diesel generator



  • At times, starting it during cold mornings can be challenging 


  1. DuroStar DS7000Q – Dependable Power & Great Value


This DuroStar DS7000Q is a great machine to depend on for powering up your home when there’s an outage. It is powerful enough to power kitchen appliances, heating units, and water pumps in your home. 


With its clean-burning diesel engine, this generator delivers 6000 surge wattage and 5500 rated watts which is reasonably enough for serving emergency power needs. It can achieve a runtime of about 12 hours at half load on a single tank, thanks to its 3.83 gallons fuel tank size.


This model offers three starting options; 


  • An integrated one-touch electric start makes it easy to start or stop the unit.
  • A remote control functionality. You can start and stop this generator from the comfort of your house.
  • A conventional recoil starter acts as a backup starting plan should the first two fail to work. 

This unit has four total outlets: two 120V 20A outlets for your standard household appliances. For high-powered devices, this model offers single 120V 30A and 120/240V 30A twist lock outlets. You can use this generator to provide power to your AC, refrigerator, furnace, TV, etc., without worrying about tripping.


This is a heavy generator. However, it comes with a wheel pack that makes it stress-free to move once it’s on the ground.


  • The model has a wheel kit
  • Electric and remote start and stop features


  • It is expensive to maintain


  1. Pulsar PG7000D Diesel Generator


This power equipment is an efficient workhorse ideal for powering your home appliances during a power outage. This model has a starting wattage of 7000 and running wattage of 5500, which means you can use it to run your refrigerator, microwave oven, TV, lights, and other household appliances.


It also has a fuel tank that can hold up to 4 gallons, offering a decent runtime of 9.5 hours at 50% load. With this runtime, you can be sure that your essential appliances will keep running during a power outage. It has a fuel gauge for convenient assessment of fuel level and helps you know when you need to refuel it.


Starting it up this model is pretty easy either through a standard recoil-pull start or an electric push-button option. The recoil-pull option is ideal when the generator battery has no charge. So, if you want to enjoy the electric push-button, you need to maintain the battery charge constantly.


This unit’s control panel holds a digital hour meter and a voltmeter that shows how much power is you are consuming. This generator offers you several power outlets:

  • Two 120V 20A outlets
  • 120V 30A TwistLock outlet
  • 120/240V 30A TwistLock outlet
  • 12V 8.3A DC outlet


According to the manufacturer, this generator operates with less than 70 decibels. While this is not a silent generator, the noise level is relatively low, considering it’s a diesel engine and high power output.


This fully enclosed generator has a weight of about 350 pounds. It has four wheels, and an integrated pull handle for easy moving once it is on level ground.


  • It’s one of the cheapest high-powered portable diesel generators.
  • It has multiple power outlets, including a 12V DC port.


  • It is not durable


Cummins Onan Quiet Series RV QD10000 (Best Mounting Generator for RVs)


This reasonably priced generator can power all of your appliances in an RV. It is also perfect for backup power at home. It’s a durable machine that will offer you years of service. It has a voltage regulator and automatic idle control to help conserve fuel and extend the engine’s life.


This generator offers two 120-volt 20 amp outlets, one 120-volt 30 amp outlet, and a single 240-volt 50 amp outlet. With its rated wattage of 10000 of clean power, this machine can easily power your AC, refrigerator, furnace, and other appliances without any problems. It also has a fuel tank that can hold up to 11 gallons of fuel. This ensures that you have plenty of runtime for all your needs.


This is a diesel generator, but it operates quietly. It is rated for a noise level of 60 decibels when running from 50 feet away and 70 decibels when operating from 10 feet away. The low noise level is because of its full enclosure design. 




  • It is quiet at just 60 decibels when running


  • User-friendly features




  • It is a heavy generator with no wheels nor handles to ease its movement.


Benefits of Buying the Best Portable Diesel Generator

Besides the low cost of buying portable diesel generators compared to gasoline models, it has several other advantages. Some of these benefits include:


Fuel Efficiency

Best Portable Diesel GeneratorDiesel generators are more fuel-efficient than their gasoline counterparts. This is because diesel generates about 15% to 20% more power from the same fuel than a gasoline generator uses. Since diesel is also cheaper compared to gas, you will end up spending less on operational costs and, at the same time, produce more power in the process.



Diesel engines are known to be more durable than gasoline engines. This is because diesel fuel doesn’t have the same properties that can cause knocking and pinging in a gasoline engine. As such, you will get more years of use from your diesel generator before it needs any major repairs or replacements.


Low Maintenance Costs

Generators that run on diesel require the least maintenance. Usually, you will only need to service them once a year. Diesel has a long shelf life of up to 12 months. When you store the fuel for several months, it will not clog up your generator’s carburetor or fuel system as gasoline does. That way, you will get the best performance from your generator for a long time.



Since diesel generators are used in different outdoor situations, they will find their way into homes and other premises that need reliable power sources. Diesel generators don’t break down as often as gasoline engines do, making them more favorable for use at home and offices, where even a few minutes of a power outage can cause significant disruptions.


Operate with Low Noise Output

Modern diesel engines have low noise output compared to the traditional models. This helps to reduce noise pollution when the generator is in operation. Modern models have high efficiency, requiring less energy, which means the motor does not run at full speed, hence the low operational noise.


Buyer’s Guide

When shopping for a portable diesel generator, there are some factors you need to consider. These include:



The first thing you need to know is the amount of power your appliances will require. Add up all those watts and divide them by 120 volts to get the amps you need. It will help you choose a generator with enough power to run all your appliances without any problems.


Will you be running sensitive appliances? If yes, you will a diesel generator that produces clean sine wave and has a surge protector. In our review, Generac 6864 is perfect for powering sensitive appliances like laptops and smartphones.



Where will you be using the generator? If you will be using it at home, then a heavy generator with wheels and handles is not necessary. However, if you need to move the generator around for outdoor activities like camping or a job site, you need a portable model. The best portable diesel generator comes with wheels and strategically placed handles. Wheels and handles make them easy for transportation.


Noise Output

Where will you be using the generator? If you will be using it at construction sites, then the noise level is not a problem. However, if you will be using it to power appliances at home or for recreational activities like camping, you need to get a low noise output generator. In our review, Cummins Onan Quiet Series RV QD10000 is the best for quiet operations.


Fuel Type

Diesel generators are available in both diesel and gasoline models. You need to decide which one you want depending on your needs. Diesel generators usually have long runtime hours, and they don’t break down as often as gasoline generators. 


Generators come in a wide range of prices from a few hundred dollars to a few thousand dollars. You need to decide how much you are willing to spend on a generator and then find one that fits your budget.


Additional features: Look out for other features like;


  • Electric and Remote start functionality: This comes in handy, especially if you will be using the generator for outdoor activities. With an electric start, you need to push a button, and the generator will start. With remote start, you can start the generator from a distance.
  • Built-in fuel gauge: This will help you keep track of the fuel level and know when to refill.
  • Hour meter: This tells you how many hours the generator has been used.
  • Automatic shut off when the fuel level is low: This feature will prevent the generator from running dry and damaging the engine.
  • Warranty: Diesel generators are expensive. You need to ensure you get one with a warranty so that the manufacturer can replace or repair it if it breaks down within the warranty period.


Frequently Asked Questions

  1. What is the best brand of diesel of generator?

Cummins is the best diesel generator brand. It manufactures top-of-the-line generators that are reliable and efficient. Cummins Onan Quiet Series RV QD10000 is the best diesel generator in our review. Cummins generators are also backed by a warranty.


  1. Who makes the most fuel-efficient generator?

Generac manufacturers, followed by Honda, are the best manufacturers of fuel-efficient generators. In our review, Generac 6864 is the most fuel-efficient generator. It has a runtime of 32 hours on a 50% load and a 12 gallons diesel tank.


  1. What is the quietest diesel generator?

The quietest diesel generator is the Cummins Onan Quiet Series RV QD10000. It operates at 60dBa, which is equivalent to background noise. It is perfect for recreational activities like camping and tailgating.


  1. What is the smallest diesel generator?

Dewey Electronics MEP-531A generator is the smallest portable diesel generator. This generator is used by the US military.


  1. Are diesel generators efficient?

Yes, diesel generators are more efficient than gasoline generators. This is because diesel fuel has a higher octane rating than gasoline. This means diesel generators can run for more hours than gasoline-powered models when running at the same capacity. In some cases, the consumption of diesel engines is about half that of comparable petrol engines.


  1. Does Generac have a diesel generator?

Yes, Generac manufactures diesel generators. In our review, we have featured Generac 6864 GP6500E as the best diesel generator. This generator is durable and has a long runtime. It also comes with a warranty from Generac.


  1. What is the most reliable diesel generator?

Cummins is the most reliable diesel generator. It manufactures top-of-the-line generators that are reliable and efficient. Cummins Onan Quiet Series RV QD10000 is the best diesel generator in our review. Cummins generators are also backed by a warranty.


  1. Who is the largest manufacturer of generators?

Caterpillar Inc., based in Illinois, USA, is the biggest manufacturer of generators in the world. The company produces a wide range of generators for residential and commercial use. It also has a wide range of prices to fit any budget.


  1. Which brand of generators is the best?

Honda is the best generator brand; it is known for its quality and durability. Generac manufacturer comes as a runner-up. Generac generators are known for their affordability and reliability.


  1. What is the most efficient generator design?

The most efficient generator design is the vertical design. This type of generator takes up less space and is easy to transport. It also has a longer lifespan than the horizontal design. Yamaha EF6300iSDE is an excellent example of a vertical generator.


  1. What is the quietest generator?

The quietest generator is the Honda EU2200i inverter model. It has a noise output level of 48 decibels, and it is only powered by gasoline. Yamaha EF2000iSv2 comes second with 51 decibels.


  1. How long will a diesel fuel generator last in a tank?

Diesel can last for up to 12 months in a tank if the generator is not in use. After 12 months, it will start reacting with oxygen found in the tank, leading to a gummy substance. If you use the generator frequently, you must refill it.


  1. How many types of diesel generators are there?

There are two main types of diesel generators. They include; portable and standby generators. The portable models come with wheels and handle for easy transportation. While standby models are permanent, you can only move them by truck.


  1. How many watts do you need to power a house?

Best Portable Diesel GeneratorThis depends on the size of your house and the appliances you want to power. A small house with a few devices will only need about 3000 watts. However, for large homes and those who want to power up many appliances, you will need a generator with at least 10000 watts.


To be precise, calculate your total watts demand by summing up the starting wattages of all your appliances. Then, add an extra 1000-watts to that number to ensure you have enough power. For example, if your total wattage demand is 4000 watts, you need a generator that can provide up to 5000 watts.


  1. How long can a diesel generator run continuously?

This will depend on the size of your diesel generator and the amount of power you are using. The larger generators can run for more than a day, with some going for up to 72 hours before refueling. However, the smaller generators will only run for a few hours continuously.


  1. How much diesel does a generator use per hour?

It depends on the size of the generator and how many watts it is producing. A small generator of 10 kW size generator running on a 50% load consumes about 0.53 gal/h, but when the load is full, it will consume 0.8 gal/h. While a 20KW model will consume 0.9 gal/h when running at 50% load and 1.6 gal/h at full load.


  1. Are diesel generators better than gas?

Diesel generators are more efficient than gas generators. They also run longer on a fuel tank and are less likely to experience power surges. However, diesel generators are heavier and can be noisier than gas generators. They are the best option for anyone looking for a generator that can run for long hours. They also have a longer lifespan and are less prone to breaking down.


  1. Which oil should I use in a diesel generator?

The best oil for a diesel generator is the one recommended by the manufacturer. However, if you have a small generator, use any motor oil that has an SAE rating of 40 or 50 and it should be suitable for your needs.



Diesel generators are a great option for anyone looking for a reliable and efficient generator. They are more expensive than gas generators, but they offer much better performance. If you are an RV reveler, We recommend the Cummins Onan Quiet Series RV QD10000 as the best diesel generator on the market. A warranty backs it, and it is very reliable. But if you are looking for a generator for your home and outdoor power needs, go for Generac 6864. The Pulsar PG7000D is ideal for anyone looking for a cheap portable diesel generator.

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About Steve Stuart

Steve Stuart is an electrical engineer who developed interest on generators during his school years. After school, he became a generator enthusiast. This is after encountering power supply problems at the area of residence where he lived. Power would be on and off and so food would go bad and the room heater would go off especially during winter. After trying the different generator brands for several years, Steve now provides information on the available brands and products in the market today. Based on his experience, he gives the do’s and the don’ts when it comes to generator use.

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