Operate tools, appliances, & sensitive electronics. (Buy from Amazon)
Best Portable Diesel Generator
Internationally, Diesel generators are the most popular when more power is needed. In the US, most homeowners and even many contractors seem to prefer gas-powered generators. Though when it comes to hard-working high-powered generators, diesel engines are the best.
Why would you want a portable diesel generator?
If you look at any large construction site, you’ll see that most of the equipment use diesel engines and there’s a very good reason for this. A diesel engine provides a lot of torque at low revs. This is very beneficial when your equipment is working under load. Diesel engines don’t experience as great a drop in the RPM as the load increases. This is of particular importance when using a generator that needs to run at constant revs to ensure a stable power supply.
One of the many benefits of using a diesel generator is that they don’t overheat as easily and they adapt to load changes much better than gas generators. If you’re using high-current equipment like large power tools, even refrigerators, and air conditioners, a diesel engine won’t feel as much strain when these appliances and tools start. So, even if the diesel generator that you’re using might not have very high starting watts, the voltage drop when it goes into overload, won’t be too high. The end result is lower harmonic distortion, a diesel generator will generally have a more stable current than a gas-powered machine. There isn’t much need for an inverter when running the generator on diesel fuel, an automatic voltage regulator (AVR) is all that it needs to supply power for sensitive electronics.
DuroStar DS7000Q | Excellent Value Portable Diesel Generator
You get a lot for your money with this great little generator. (Buy from Amazon)
When one looks at fuel consumption, diesel engines are always the best. You’re going to get extraordinary runtime from a tank of fuel when you compare diesel to gas generators. This is a great convenience. With a big enough fuel tank, a diesel generator will run all day without the need to fill the tank. Of course, there will be a cost saving. Depending on the cost of diesel in your area, you can experience significant savings. Even if you’re paying more for diesel than gas, you’ll probably be saving money simply because you’re burning through a lot less diesel. The benefits of diesel runtimes will become abundantly clear when we review the best portable diesel generators.
Another distinct advantage to using diesel fuel is the safer and more convenient storage and transportation of your fuel. I say more convenient because you’re using so much less fuel. You’ll be getting up to double the kilowatts per hour from a gallon of fuel when using diesel instead of gas. The safety advantage is something to consider. Gas is extremely volatile, it vaporizes very easily. This means that the fumes released from a gas can ignite with even the smallest of sparks. A small spark resulting from static electricity can cause gas to explode.
Diesel, on the other hand, requires extreme pressure and/or heat before it ignites. A diesel engine requires enormous amounts of compression for the combustion cycle when compared to a gas engine. Under normal atmospheric pressure, diesel needs heat before it combusts. This means that you need to expose diesel fuel to an open flame for a few seconds before it will burn. There’s no chance of diesel exploding from a spark.
Diesel engines outlast gas engines by a long shot. This means that you’ll get many more years of reliable service from a diesel generator. While the initial cost of buying a diesel generator is likely to be more than a gas-powered alternative, the savings over the lifetime of the generator are significant. Personally, for a generator that produces 5000W and upwards, diesel is my preferred option.
Reviews | Best Portable Diesel Generators
It’s clear that there many benefits to using a diesel generator. Because these engines tend to be tough industrial units, the general construction of the generator usually matches this – you’re getting a very durable machine.
Because these generators are made to last, it’s always worth paying a little extra. Because you’re likely to be spending more, it’s important to ensure that you’re buying the best portable diesel generator. This review is going to help you decide, by taking a detailed look at three incredible portable diesel generators.
- Generac 6864 (XD5000E) – For a high-grade industrial diesel generator, this model comes at a very reasonable price. Not the cheapest – but one of the best.
- DuroStar DS7000Q – True to the brand’s reputation, this is a very cheap generator for what you’re getting. It’s been included in this review as the best budget diesel generator.
- Gillette Generators GPED-65EK Gen-Pro – Best of the best. As the most expensive generator in this review, the Gillette model has a very impressive spec level and is exceptionally durable.
From this selection of portable generators, there’s one for every type of generator buyer. If you’re looking at affordability, ultimate quality, or something in between, you’re going to find it here.
Generac 6864 — XD5000E
Best Portable Diesel Generator for the money. Perfect for homeowners.
435cc air-cooled direct injection, industrial-grade diesel engine.
Features:
- Diesel power requires less maintenance, is more efficient, and provides a long life.
- Engine : Yanmar LW Series — 435cc air-cooled direct injection, EPA Tier IV, industrial-grade engine.
- Less than 6% total harmonic distortion for clean, smooth, operation of sensitive electronics, tools, and applications.
- Large-capacity 12 gallon fuel tank with fuel gauge provides a long run-time of 32.4 hours at 50% load.
- Compression release lever provides easier starting during cold ambient temperatures.
- Low Oil Pressure Shutdown automatically safeguards engine from damage.
- Fuel primer bulb provides quicker starts when the fuel tank has previously run empty.
- Durable, fully welded 1 ¼” steel frame.
- Integrated lifting eye provides easy transport and security on the jobsite.
- 120/240V selector switch provides full 120V power.
- Single touch electric start provides hassle-free start-up (battery not included).
- Hour Meter with maintenance resets tracks usage and monitors maintenance cycles.
- Recommended : Generac 6910 wheel kit : (sold separately)
✓ View or download the BROCHURE or the SPEC SHEET for the Generac 6864.
Features:
Out of the three generators in this review, the Generac 6864 is in the middle of the price range. In a sense, I feel that this is the best value for money out of the three. It is of a very high quality standard and is built for hardworking site conditions. While it compares favorably to the best industrial-grade portable diesel generators, it is lacking in a few areas – though this nothing too serious. When it comes to price vs quality, this diesel generator deserves some serious attention.
The power to drive this rather magnificent generator is derived from a Yanmar LW series 435cc air-cooled, direct injection, diesel engine. This has been my first encounter with these engines, so I decided to do some research, fearing that this may be one of those unknown manufacturers to come out of Asia. My ignorance is somewhat embarrassing. As it turns out, Yanmar is a highly respected Japanese manufacturer of industrial and agricultural machines with their headquarters in Osaka, Japan and US headquarters in Adairsville, GA. This went a long way toward putting my mind at ease. Yanmar is a large international company and is fully represented in the US, so you will be able to get the support that you need.
Has a single touch electric start for quick & easy start-up.
Moving on from this, I needed to take a better look at the Yanmar L100W engine used in the Generac 6864 (XD5000E). It is an impressive work of engineering and this puts it up there with any of best diesel engines that I’ve come across. Like most of the best modern diesel engines, it uses direct fuel injection and is counterbalanced for perfectly smooth operation at high speeds. Vibration used to be a big issue with older designs for diesel engines, that won’t be the case with this one. It delivers excellent power – 9.3 HP at 3600 RPM.
It also has an excellent muffler and is designed to run quietly, making it suitable for residential neighborhoods. It appears that Yanmar is perfectly geared to the US market, this engine is final tier 4 EPA and CARB compliant. So, if like me, you once knew nothing about these engines, now you know. This is a great engine and, like any decent modern engine, it has low oil shutoff.
Do yourself a big favor and get the Generac 6910 wheel kit : (sold separately)
Wheels will certainly make this large generator very mobile. (Amazon)
Another area where the Generac 6864 (XD5000E) stands out is in the incredible runtime that you get. It has an enormous 12-gallon fuel tank which provides 32.4-hours of continuous power at 50% load. This works out to 6.75 kilowatt-hours per gallon of diesel. In the introduction, I mentioned the fuel savings that you get from a diesel generator, now would be a good time to elaborate on this. The best fuel consumption that you can get from a gas-powered generator is a little over 5 kilowatt-hours per gallon, generally, it’s less than 5. So comparing these figures, the Generac 6864 is 20-30% more fuel efficient than the average gas generator.
The more you use your generator, the more you’re going to save. Then there’s the sheer convenience of being able to run your generator all day long without topping up the fuel tank. In addition to this, the Generac has one-touch electric starting. So before you start the day’s work, all you need to do is fill the tank, press the start button and you’ll be able to continue uninterrupted for the rest of the day. The fuel cap has a fuel gauge fitted to it, so it’s easy to see how much diesel is in the tank.
Beautifully engineered as Generac products always are. (Buy from Amazon)
The alternator is a perfect match for this already impressive engine. Load changes are barely noticeable with Total Harmonic Distortion (THD) of less than 6%. This is on the higher end of the scale for a diesel generator, I prefer to see a figure of less than 5%. Though my experience of diesel generators is that they almost never reach maximum THD. My guess is that it will seldom be more than 3%, which is the accepted standard for an inverter. Even with temporary spikes that may reach 6%, it won’t cause any damage to sensitive electronic equipment.
The constant power output of the Generac 6864 is 5000W. The only real issue that I have with this generator is that it doesn’t have a high peak wattage – only 5500W. A starting wattage that’s only 10% higher than the continuous power output does limit the number of high startup electrical appliances or tools that you’re able to use at any given time. For example, a 1HP air compressor requires a startup current of around 4500W, this means that you can’t be using much more than this when the compressor starts. So you’ll need to exercise some degree of power management on busy construction sites or homes where you’re using a lot of heavy appliances (refrigerators, air conditioners, or heat pumps). That being said, this is my only complaint about the Generac and it is manageable.
Monitors your run time and tracks maintenance intervals.
I really like the 1¼” steel tubing frame, it is true industrial quality. The robust frame also has vertical support in three places – most only have two. The central tubing also acts as a lifting eye to make the generator easier to load onto a truck. This will be much appreciated, as it weighs a whopping 252 LBS. Though this weight is a clear indication of the amount of heavy-duty steel that’s been used in its construction. It has a stronger than average wheel kit with a sub-frame and large never-flat wheels. You will, however, have to buy this separately. The 12V battery for the starter is also sold separately, which is a little disappointing.
Lifting eye allows for easy transport and security on the jobsite. (Amazon)
The control panel continues to display the rugged intentions of this generator. The switches and outlets are obviously made to last and the entire machine is designed to take some knocking about without things breaking too easily. It has a 2-pole main circuit breaker (23A to allow for the peak load output). You also get every type of outlet that one would be using. There are two duplex 120V, 20A (NEMA 5-20R) outlets with GFCI protection and individual 20A breakers for each outlet. It also has a 120V, 30A, twist-lock (NEMA L5-30R) outlet, and a 120V/240V, 30A, twist-lock (NEMA L14-30R) outlet, these circuits are protected by a push 30A breaker. Though, since the main breaker trips at 23A, the 30A breakers are basically redundant when running 240V. It also has a selector switch for 120V only, or 120V/240V operation and a digital hour meter.
When I look at the price of the Generac 6864, it looks like a real bargain to me. The peak wattage is not as great as I would have liked and you have to pay a little extra for the battery. Though it has a recoil starter, so you can do without the battery. Despite these minor issues, it’s incredibly good value for money for a genuinely industrial grade diesel generator. The fact the 2-year warranty applies to both residential and commercial use testifies to the heavy-duty intentions of this generator. Many manufacturers only offer a 3-month warranty for commercial use.
DuroStar DS7000Q
Best portable diesel generator if you’re on a budget.
Fully enclosed frame. Wireless remote is a nice touch.
Ideal for use on farms and ranches, maintenance, construction, and even emergency power.
Features:
- Starting Watts : 6,000W / Running Watts : 5,500W
- 418cc DuroStar 4-stroke single-cylinder direct injection engine.
- Wireless Remote start and/or Electric start
- Maintenance-free alternator with automatic voltage regulator.
- Control panel includes : keyed ignition, oil alert automatic shutdown (low oil pressure), volt meter, circuit breakers, low fuel indicator and power outlets.
- 12 hours run-time at 50% load on a single tank of fuel.
- Fully protected 12-volt, 120-volt and 240-volt outlets.
- Ground fault interrupter 120-volt outlet (GFI) for safe operation.
- Vibration isolation mounting between engine/alternator feet and base frame reduce vibration
- Quiet muffler and soundproofing reduces engine noise
- Fully enclosed frame
- Size : Length 37.8″ / Width 22″ / Height 30.3″
- Weight : 305 lbs.
- Outlets
- (2) 120-Volt, 20-Amp, 3-Prong
- (1) 120-Volt, 30-Amp Twist-Lock
- (1) 120/240-Volt, 30-Amp Twist-Lock
Includes :
- DuroStar DS7000Q Silent Diesel Generator
- Remote for Remote Start
- Battery for Electric Start
- Maintenance Tool Kit
- Owner’s Manual
Overview
Some people may be more familiar with the DuroMax brand. Both DuroStar and DuroMax generators come from the same factory and are often the exact same units with different branding. So whether you’re looking at DuroMax or DuroStar generators, one thing remains the same – extremely good value for money. I’ve had a look at many different generators (with either of the branding) from this company and one thing always jumps out at me, you’re getting a lot for your money. Although they’re generally the cheapest in their class, DuroStar generators are quality items and have a spec level to rival the best of them. The DuroStar DS7000Q is bound to impress the harshest of critics, even if you ignore the incredibly reasonable price tag. This is by far the best portable diesel generator for its price. It beats many that cost a lot more.
A practical control panel that makes it easy to operate.
Easy to read and use control panel. (Buy from Amazon)
A first look at the DuroStar DS7000Q reveals a completely different design to the other two in this review. It has an enclosed housing which can be an advantage for some, though not everyone will appreciate this. The steel enclosure helps protect the generator from dust and moisture. Though, more importantly, it reduces the noise levels considerably. For use at home or to provide backup power to a store or office, this is great.
If you want a diesel generator to take camping or to use on a construction site, the DuroStar DS7000Q might not be the best. It’s certainly robust enough, the steel enclosure is tough and protects the machinery from damage. However, this design makes it way heavier than the others in this class. It weighs 305 LBS so, yes, it’s going to be a tough job loading this generator onto a truck. It does have a heavy-duty lifting eye, which will make it easier if you have the correct lifting equipment. So, although heavier than most, it’s still portable.
Another thing that might be a problem if you’re going to be moving the generator over rough terrain is the wheels. It has four caster-style wheels which means it will glide effortlessly over a smooth floor or paved surface. But these wheels are not as large as the wheel kits used on the open frame generators and this will make it basically impossible to move the generator on a gravel surface. I really like the enclosed design, but it depends very much on where you intend using the generator as to whether this will be an advantage.
When the power goes out you’ll be thankful you have this ready to go.
The 186F, direct injection, 418cc engine seems, by all accounts, to be a great piece of machinery. I cannot confirm the origins of this engine and, therefore, I can’t say too much about it. What I’ve read in customer reviews is that this engine is a hassle-free, easy to use unit. It has a very quiet muffler (with a spark arrestor) which, combined with the enclosure, makes it one of the best diesel generators for applications where noise reduction is essential. The engine has electric starting and low oil shutoff. As an emergency backup, it has a recoil starter and you have the convenience of a wireless remote control. So you don’t have to be at the generator to start it, which is great when the generator is quite far away and even better in bad weather.
The alternator has low vibration mountings which reduces wear and, therefore, your long-term maintenance issues. It also delivers more power than the more expensive Generac 6864. The DuroStar DS7000Q provides 5500W continuous running power with a peak of 6000W. While it has a much smaller 3.83-gallon fuel tank (with a fuel gauge), the incredible fuel efficiency of this generator compensates for this in a big way. The DuroStar will run for 12-hours at 50% load from this comparatively tiny fuel tank. This calculates to a breathtaking 8.6 kilowatt-hours per gallon, that’s twice as good as some gas-powered generators! Even when compared to other diesel generators, this is a huge fuel saving.
They don’t provide HD specs for this generator. It has a good AVR and I would expect the current to be as stable as any of the best diesel generators. I doubt it will exceed 6% THD.
Uses a direct fuel injection system for low fuel consumption. (Amazon)
The control panel is logical and easy to understand. It has a comprehensive setup with all the outlets one needs. This includes two 20A, 120V household outlets with GFCI protection (NEMA 5-20R); 120V and 120V/240V, 30A twist-lock outlets. Each of the outlets has their own push circuit breaker and there’s a main 2-pole circuit breaker. It also has an 8.3A 12VDC port for battery charging and an analog voltmeter. The only thing missing is an hour meter. It has an easy to use starter with a key and a selector switch that toggles between 120V and 120V/240V AC output.
You can compare the DuroStar DS7000Q to generators that $1000 more and still be hugely impressed. It’s not only cheap to buy but is also very economical to run, with about the lowest fuel consumption I’ve ever seen. This leads me to the conclusion that this is by far the best budget portable diesel generator on the market. The 1-year commercial warranty isn’t the best, but still better than many. For residential use, it carries a really good 3-year warranty and you’ll get a 30-day satisfaction guarantee. Even if you ignore the incredible price, this is an amazing deal.
Gillette Generators GPED-65EK Gen-Pro
Best portable diesel generator that you probably weren’t aware of. Truly an underrated brand and worth the money.
Gillette has been making generators since the 1960’s.
Features:
- Starting Watts : 6500W / Running Watts : 5000W
- Engine : KOHLER KD420
- 12 volt electric start with built-in battery charger
- EPA/CARB : Tier IV certified
- 3 year limited warranty
- Engine hp@ 3600 rpm : 9 hp intermittent use, 8 hp continuous use
- Engine displacement : 1 cylinder, 24.5 cu. In. (401 cc)
- Engine air cleaner : heavy duty, low profile, dual element filters
- Fuel tank gal. (liters) : 4.0 gal. (15 l.) Metal fuel tank with gauge, twist-cap, & slosh valve
- Engine oil system : full pressure with spin on oil filter, 1.6 qt. oil sump
- Low oil protection : automatic engine shutdown protection at low oil level
- Noise Level : 78 Db(a) at 7 meters
- Run-time : 5.63 hours at 3/4 load
- Motor start power : 1.5 hp, code G electric motor
- Crane pick-up hook : optional equipment : central pick-up on top of gen-set
- Optional : 2-wheel dolly kit : complete with (2) handles and “never go flat” wheels
- Mainline circuit Breaker : 25 amp, double pole circuit breaker for 240 vac, main breaker
- Hour meter : Run time hours, plus (3) maintenance alerts: 25 hour change oil, 25 hour change, Oil filter, 25 hour service air filter
- Power receptacles : (2) nema 5-15r 120 volts, (1) 14-50r & (1) l5-30r receptacles
- Protective roll frame : rugged 1-1/4” round roll frame, protecting entire gen-set
- Shipping weight : 239 lbs.
Overview
This is the most expensive generator in this review, though it has a few characteristics that exceed expectations. If you don’t mind paying more for the best portable diesel generator, the Gillette GPED-65EK is worth considering. You’re getting a lot for your money and the general quality of this product is indisputable.
I’ve had a lot of experience with Kohler engines and this gives me complete faith in this generator. The Kohler KD420, 401cc, direct injection, diesel engine is as tough as nails. This is a legendary diesel engine and is tier 4 EPA and CARB certified. It has the convenience of an electric starter. The power is great, it delivers 8HP (at 3600 RPM) continuously with a short peak of 9 HP maximum output. This produces 5000 watts of continuous power and 6500 watts of peak power through a superb brushless alternator with a remarkable AVR which ensures that the THD will never exceed 5%. That’s the best THD figure that you’ll get from a non-inverter generator. It has low oil shutoff and is a reasonably quiet unit, 78 dB(A) maximum from 21-Feet.
Recommended Gillette Wheel Kit : Purchased Separately
Personally, wheels are essential for a heavy generator like this. (Amazon)
The fuel consumption is great, falling between the remarkable DuroStar and the very reasonable Generac at 7.5 kilowatt-hours per gallon. This means that you’ll get 10-hours runtime from the 4-gallon fuel tank at 50% of the rated load. The tank has a gauge, like the others.
The open steel frame is very durable and it makes use of high-quality rubber mountings. It also has an oversized industrial air filter which adds to the heavy-duty nature of this generator. The control panel is nicely protected from damage and has all the outlets that you’d find on any generator of this class. There are 4 X 120V, 20 household outlets with GFCI protection. Naturally, you’ll also get both 30A twist-lock outlets for 120V or 120V/240V. All the circuits are protected by circuit breakers and it has a 25A 240V, 2-pole main breaker. It also has an hour meter as well as a voltmeter.
Despite being really tough, this is the lightest generator in this review, weighing 207 LBS. Like the Generac, you have the option of buying the wheel kit separately, this includes two super heavy-duty wheels and strong fold-down handles. A lifting eye is also available as an optional extra.
With its stellar reputation, ultra-heavy-duty design, and a high spec level, it’s paying a little extra for the Gillette GPED-65EK. This generator is built to an exceptionally high standard is going to withstand anything that that it’s exposed to – within reason, of course. It can easily be considered the best portable diesel generator on the market. The generator is subject to the standard Gillette 2-year warranty and the engine has a 3-year warranty.