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Diesel Generator Reviews: Best 3 And Ultimate Buying Guide

Purchasing a diesel generator is not something easy. You need to figure out all the needed information for the purchase. Down below is everything that you need to know, starting from the brand suggestions to the buying guide. Read them carefully before you decide on what generator product to purchase eventually.

The Best Product to Choose

These are three of the best products when it comes to generator of this kind. They are all offering great performance and everyone can basically use them flawlessly. Here they are for you to consider and compare. By doing so, you won’t get disappointed when the actual product comes as you have been spending time considering the pros and cons of them.

Best 3 Diesel-Powered Generators

1. DuroStar DS7000Q

The first diesel generator here is from DuroStar. This generator is mostly used by those who want to powered houses in smaller size. The generator has numerous great features that you have to consider. First of all, it has the ability of producing some massive 6,500 watts of power. They are just more than enough to power up a small flat or house.

The diesel generator is not hard to start and it is like just one push a button away. Besides of that, the generator will remind you if there are a lot of things that goes wrong with them, including low fuel and low oil. The best thing about this generator is that you can use them quite quietly. They are completed by muffler and vibration operation. Using the generator won’t even bother your surroundings.


  • It has 4-stroke engine for better performance
  • It comes with 6,500 Watt capability
  • Electric start is available
  • It has 3,8 gal/hr fuel tank capacity
  • Oil alert is available
  • Low fuel indicator is available
  • Vibration isolation feature is available
  • It uses super quiet muffler


  • The wqarranty is not disclosed

2. Generac 6864, 5000 Running Watts/5500 Starting Watts, Diesel Powered Portable Generator

The next diesel generator is from Generac. If you have been involved in the world of generator for a while, you will probably notice that the best generator often comes from Generac. This product is one of the best for sure. Seen from the power production available, the generator has the ability to produce 5,500 watts. It has single touch feature for the start. Besides of that the generator is also capable in making sure that you can transport them with ease.

Yes, this diesel generator is a portable one with handle on top. You can easily lift them to power up anything, including gadget, appliances and many more. For those who want to make sure that they generator is going to last for good, this one is the best as it has steel cradle to enforce the strength of the generator. This product has amazing performance and feature for everyone to consider them for sure.


  • It has massive 5500 Watts power
  • Single touch electric start is available
  • It is designed in 120/240 V voltage selector
  • Built-in hour meter is available
  • Steel cradle can enhance the strength
  • Air-cooled direct injection machine is used
  • It has 12 gallon fuel tank with 32, 4 hours of run time (50%)
  • It is generally easy to transport with its lifting eye


  • It needs to get rested every now and then to produce the power

3. Cummins Onan Quiet Series Diesel RV Generator

Last but not least, there is this diesel generator from Cummins Onan. It has numerous features that you can get and use. Basically, this is the generator that you need to use in an RV. Yes, using this generator, living in a RV won’t be such a hardship anymore as the electricity will keep being produced from time to time. The generator has hour meter for you to easily control the usage of the generator.

Besides of that, the diesel generator also has the ability of producing constant and steady power. It has the ability to power several appliances at once. The power generating ability is around 10kW. It has digital voltage regulation for you to use as well as auto shutdown feature. You can take the benefit of this generator by using its extremely quiet feature.

Your RV neighbor won’t get bothered by the noise and buzzing produced by generator as this one does not produce it almost at all. This is why the generator needs to be a choice when you are looking for the best one for the RV.


  • Hour meter is available for better control
  • It can power 3 rooftop air conditioners
  • It’s extremely quiet
  • It has Constant Speed Operation
  • It comes with massive 10 kW power
  • Auto shutdown feature is available
  • It has compact design and Digital Voltage regulation


  • It is probably too big for some RV types

Diesel Generator Buying Guide

Buying diesel generator is not something to take for granted. This kind of heavy machinery is expensive and you will have to consider a lot of things before buying one. Of course, the main point of getting the generator is to have an extremely reliable backup power source. To achieve that goal, here are some things to consider while buying the generator.

  • Brand Reputation

It is probably very unwise to still considering a brand rather than its performance. However, sometimes it is very true. More well-established brands are just better in its products and their performance. So, it is suggestible for you to buy diesel-powered generator coming from well-established brand or manufacturer with great reputation.

  • kVA Size

kVA size is the kilovolt ampere or basically the capacity of the generator in generating the electricity. Consider your need here. If you need the generator to power up large houses and building, you need to buy a diesel generator with large kVA size instead of the small and medium one.

  • Control System

A good diesel generator should have control system. This is the system to make it easier for the owner to control all types of levels on the machinery, including oil level as well as the fuel level. If your diesel-powered generator does not have this feature, you should not have bought it as this control system is very essential.

  • Power Management System

A lot of people consider that PMS or Power Management System is not that important. However, when you get a diesel generator, PMS is like one of the most important things there that you have to consider. The PMS includes the ability of the generator to start quickly, the ability of the generator to get paired and many more. It enhances the overall performance of the generator.

  • Fuel Efficiency

Even though diesel is the main core of the generator, you cannot ignore the fact that the machine won’t start without fuel. This is why you need to consider the fuel efficiency of the diesel generator, especially because diesel fuel is way more expensive than gasoline or natural gas fuel.

  • Physical Size

Let’s be frank here and admit that when it comes to size and portability, all diesel generator products are just massive. They are like big boxes that you won’t be able to carry easily. It is because the components and machine in there are just bigger and heavier. They are not so lightweight, too and it probably takes two to three people to move them around.

The best thing you can do about it is choosing a diesel generator that is most compact in design and the smallest one, basically. Even when the “smallest” one is not small at all, at least you can save more space by not buying the large, bulky generator.

  • The Muffler

Unlike solar generator or fuel generator that can be inverted, diesel generator still produces buzzing noise and they are quite noticeable. If you do not want to bother the neighbors with the buzzing noise, make sure that you buy a generator with great, working muffler. The muffler will at least keep the generator’s buzzing noise in low level.

  • The Price

As you can already tell, this machinery is not cheap at all. You will have to consider the price to get diesel generator. If they are exceeding your budget, you need to do more research in finding out the generator that matches the budget, probably not the diesel type but still works in producing backup power source.

How Does a Diesel Generator work?

Most people are more familiar with gas-powered generator or solar-powered one. Diesel is probably pretty unfamiliar to them. Now, there will be explanation about how diesel generator works down below. There are several major steps to explain the working phase of the generator. See the information here:

Step 1, Compressing the Air

The first step is Starting the engine. Then air circulate around the inside of generator to be compressed. It is like preparing the whole machinery to generate the heat and produce the electricity later on.

Step 2, Injecting the Fuel

Once the diesel fuel is compressed, the next thing that the machine will do is to inject the fuel. The fuel here is injected to the machine to coat all parts of the generator and start the engine to work on.

Step 3, Generating the Heat

Next, the machine will combine the process of air compression with the fuel injection process. As the result, the machine will now start to generate heat. Intense heat is produced to inflame the fuel and start a sort of combustion. At this point, the diesel generator is ready to generate the electricity.

Step 4, Producing the Electricity

Last but not least, the engine is now starting generating electricity. The electricity then gets transferred from the diesel generator to the target through the ports and ready to power up houses, building and numerous other things when the main power source is unavailable.

Advantages & Disadvantages of a Diesel Generator

Everything has advantages and disadvantages, including generators. For diesel generator, the disadvantages as well as the advantages will be displayed down below. From the information, you can have plus and minus side of generator of this kind. Then, you will be able to consider whether or not you need to buy the diesel generator.

1. Advantages

Let’s start by talking about the good thing of diesel generator. There are tons of advantages or benefits that many people can enjoy from this type of generator. Basically, it is like very efficient in many ways. Some of the advantages of the diesel generator are:

  • More steady power supply
  • Has fewer parts to replace regularly
  • More fuel efficient
  • More durable
  • Has a longer running time
  • More environmentally friendly

2. Disadvantages

What about the disadvantages? Well, there are a few of them and you can take a look at those disadvantages down below. It should help you understand that even though the diesel generator is generally good, it still has some downsides. Some of them are:

  • Massive weight and size
  • Causing noise pollution
  • Complicated installation process
  • Diesel fuel is more expensive

Diesel vs. Gasoline vs. Gas generators

The comparison between diesel generator and gas (gasoline) generator is one of the most interesting topics to talk about, especially by those who are so into backup power source. To compare both types of generator is actually not necessary. However, seen from several perspectives, the comparison between diesels vs. Gasoline is in below explanation.

  • The Performance

Seen from the performance, diesel generator is the better one. It has numerous things to surpass the performance of fuel generator. It has better kVA production and they are just more sturdy and steady when it comes to the power production.

  • The Transportability

When it comes to transportability, gas generator wins all the time. They are smaller in size and most of them are even light weighted. Unlike diesel-powered generator, they are easy to carry and basically portable. On the contrary, diesel generator is just massive and they are so heavy to transport.

  • The Cost Effectiveness

Diesel-powered generator wins this part as you will basically spend less money in taking care of generator of this kind. It does not need huge amount of fuel and they do have fewer parts of their machinery to replace every now and then.

  • The Durability

Both fuel and diesel-powered generator are very durable. However, due to its massive frame, the generator using diesel as the main power source is considered more durable as they were designed to last for decade. Of course, the durability will always come to the level of maintenance but in general both types are great.

  • The Safety

Diesel-powered generator is considered safer by many people. Gas generator needs sparks to start up the machine and they are highly flammable, too. Diesel does not need anything with flame-prone risk to start. It will be safer to use in any types of environment.

Read Also Quiet Generator Ultimate Information


̶ Which type of oil is best for a diesel-powered generator?

We do know that diesel-powered generator needs oil to run the machine and generate electricity. There are several types of diesel oil that you can find in the market. However, the best one for the generator is the full synthetic oil. This type of oil is the best option possible as they have the best ability to protect the engine.

Besides of that, full synthetic oil is also completed by the ability of handling higher temperature. That way, the generator will work more properly and they can last longer. Lastly, full synthetic oil has better ability as well to coat all the parts of the generator’s machinery. This will basically maintain the diesel-powered generator better compared to any other types of the oil.

̶ How often should I change the oil in a diesel-powered generator?

Oil in diesel-powered generator should be changed quite regularly. It is just like your car or other types of vehicle. It is suggested that if you own smaller generator, the oil has to be changed in every 50 hours of run time. If your generator is a larger one, the oil change is probably needed once every 400-500 hours of operation. Check the booklet from the diesel manufacturer to find more information about it.

What is the fuel consumption per KVA and per hour of a diesel-powered generator set?

It heavily depends on the size of the diesel-powered generator as well as the fuel consumption average of each brand. However, speaking in ball park figure, it is generally believed that for a 100 kW generator running at full load, the fuel consumption will be like 7,4 gal per hour. For a 500 kW generator, at full load as well, the fuel consumption is 35, 7 gal per hour.

̶ What are the possible causes of common faults in a diesel-powered generator?

There are two main causers of errors and damages in diesel-powered generator. Those two are basically the main reason why common faults happen on the machinery. The first one is low fuel or lack of fuel. Keep it in mind that even though the generator is using diesel machine as its main power source, fuel is still needed to run the machine.

When fuel is scarce in there, it will be quite impossible for the diesel-powered generator machine to run properly. This is the reason why lack of fuel can cause numerous types of problem including overheating and burnt parts of the machine.

The second causer is leak. Leak is extremely dangerous here. Usually, the leaking parts are including oil and coolant. Leak can really damage the whole thing. This is the reason why checking regularly for leaks are very important in keeping diesel-powered generator constantly works properly.

̶ How long can a diesel-powered generator run continuously?

It also heavily depends on the standby feature in each generator. However, in average, the diesel-powered generator should not be used more than 500 hours continuously. After 500 hours, it should be turned off and let cool. It is more than enough anyway because 500 hours equal three weeks if not more.

Those are some of the most important things you need to know about the generator. You have seen some of the best product examples, tips to buy, FAQ and more. Now, if you really need one, you can start considering buying the diesel generator very easily.