Let’s start with what an inverter is. An inverter is an electrical device used to convert direct current (DC) to alternating current (AC).
For example, you may be familiar with a common 12 V DC battery inverter, which is used to convert 12 V DC input into 120 V AC output. The inverter receives its DC input from a battery, usually a car battery or a deep-cycle battery. This DC is “inverted” to AC, giving them the name “Inverters.” However, these inverters, no doubt a good source of power, can only produce an output power of a few hundred watts.
But what if we need high power?
Well, the answer to this question is the portable inverter generator. The inverter generator is basically a combination of a conventional generator and a battery inverter.
The generator generates high frequency AC power. The AC is then converted to DC, by a device called a rectifier (opens in a new tab), and then inverted back to clean AC power. The process of conversion from DC to AC removes any ripples and fluctuations that you encounter in the conventional generators.
Advantages of Portable Inverter Generators
The conventional generator due to its noise, weight, high fuel consumption, etc. is not always an ideal choice. In such a scenario, the inverter generator tends to provide an answer to the limitations/disadvantages of a conventional generator.
Let’s have a look at some of the key advantages of the inverter generator over a conventional generator.
1. Less noise and fuel consumption
A conventional generator operates at a constant speed to maintain a required frequency of the output. For example, in the US, appliances are designed for 60 Hz. To maintain this frequency, the generator needs to operate at 3600 rpm. Whatever the amps drawn, the engine will operate at full speed, even if we only need to light a single 100 W bulb. This high-speed results in high fuel consumption and a lot of noise.
Contrary to this, an inverter generator can adjust its speed according to the load, lowering the initial AC frequency, since the inverter recovers the AC at the desired 60 Hz regardless. Thus, an inverter can operate at lower speeds to feed a smaller load. The results are improved fuel efficiency and lesser noise. e.g. in the scenario above, an inverter generator will produce 100 W to light up a 100 W bulb.
2. Smaller Size
Conventional generators can be heavy and bulky. They often require a metal frame and some wheel mechanism to move smoothly. They are portable, but rather inconvenient when it comes to their size and weight.
Whereas, inverters are usually much more compact and lighter. This makes their transportation effortless. They are easier to pick up and can also fit comfortably in your car, boat, etc.
3. Parallel Operation
Let’s assume you want to arrange a big party and you need a generator for it, as you require a power of almost 3000 W.
Your first option is a single 3000 W conventional generator. A generator of such rating will be pretty bulky. Its transportation could be a serious headache. In addition, its noise would most likely ruin your experience.
However, you have a second option, which is portable inverter generators, many of which are parallel capable—meaning that several of them may be connected in one circuit to provide more power. In this case, you can use two 1500 W inverter generators and connect them in parallel to obtain the required 3000 W.
Each inverter would probably be less than half the size of the conventional generator and would also be lighter to carry individually.
4. Cleaner and safer power
Many of our household appliances contain sensitive electronic components, microprocessors, sensors, etc. These are very sensitive and prone to damage upon fluctuations—which are often produced by conventional generators.
As already mentioned, an inverter first produces AC, which is then converted to DC by rectifiers. This DC is then inverted back to AC using an inverter (opens in a new tab). The conversion of power from DC to AC filters out any ripples or fluctuations, resulting in clean AC power, with a low THD.
Inverted generators are a relatively new product compared to the conventional generators. The factors like lighter weight, smaller size, quiet operation, high fuel efficiency, and ability to power sensitive electronics make them an attractive purchase.
However, all of this comes at a price. Although they provide savings in terms of their fuel requirements, their initial cost is higher.
With that being said, the decision between a conventional generator or an inverter is very much subjective.
If you require high power most of the time and you do not intend to use any complicated electronic device, a conventional generator would do just fine!
If you need a generator for household use where you have many electronic appliances, and you also don’t want to disturb your neighbors, then a portable inverter is a way to go!
Paul, There are conventional generators with good alternators with low THD less than 5%. This spec isn’t always stated so you might have to dig it out.
Indeed, but they are somewhat of an exception. They are listed here. If a conventional generator has a low THD, this spec will almost systematically be stated by the manufacturer, because it’s a huge selling point. If the THD is high, the spec is easily omitted 🙂
Excellent article. Very informative. Learning a lot of this after the fact!
What are you thought on generator/ inverter that run on propane? BTW, great article. Thanks
Are conventional generators capable of being in parallel with either a conventional or an inverter generator?
Unfortunately, there are no sensible ways to parallel non-inverter generators.
What is the best dB noise level they have on the market. Please advice. Thanks.
Hi Albert, you may read our article on the 10 quietest portable generators on the market. Alternatively, you can use our sorting feature to list units by ascending noise level.
Just purchased my first inverter generator. 3.4kw continuous,120v output only. I’m puzzled by it’s output — normally one side of a 120v circuit is common with ground, this one is not (I used to wire houses so this is foreign to me). I get 120v between opposite sides of receptacle but 60v between either side and ground. Is this generator wired correctly?
Your unit most likely has a floating neutral.
I find it helpful to know that inverter generators produce a safer and cleaner power because it filters our any ripples or fluctuations. My dad is thinking of opening a diner downtown, and he plans to get a commercial generator for the establishment. Our town suffers from frequent power outages, so getting a generator would be a wise choice. Thank you for this!
Very interesting article Paul! I retired from the electrical business a couple of years ago and still enjoy improving my knowledge of electrical theory. I was in my local Costco a couple weeks back and was checking out a 7KV Firman conventional generator they had for sale for about five hundred bucks. Most would think that’s quite a steal. Of course I knew why it appeared to be a steal however a husband and wife where looking at the same unit. They were all set to make the purchase when I excused myself and explained as simply as possible the possible pitfalls using a conventional generator on sensitive electronic equipment. I suggested they go home and Google THD related to generators and use the information to decide on their purchase. They thanked me very much. With the vast amount of electronic equipment in our houses in these days, these generator manufacturers should be forced to place some signage on their packaging related to THD. I’m on the Jersey coast and just suffered through the hurricane. Just purchased a Honda EU7000 inverter generator. Unfortunately I have many neighbors burning up their appliances with conventional units! Stay safe and thanks again!