Let’s Start with the Battery Inverter

what is an inverter generator batter inverterSo exactly what is an inverter generator?  To understand the portable inverter generator and how it compares to the common portable generator, we’ll first look at inverter technology in its simplest form.

You might be familiar with a common 12 volt battery inverter which is an electrical device that converts 12-volt DC power into 120-volt AC power.

Typically you run this type of inverter off of your car’s battery or off of a deep-cycle battery that you buy specifically to power the inverter.  Although fairly inexpensive, the shortcoming is that typically an inverter is a useful solution if you can keep your power demands in the 200-watt range.

You could get one with a more useful 2,500 watts, but it will cost close to $1000 and that’s not including the bank of deep-cycle batteries and a charging system.  For more demand than that, you should consider a fuel powered inverter generator.

Consider a car’s battery has a reserve capacity rating.  A typical rating is 80 minutes, which means the battery can supply 25 amps at 12 volts for 80 minutes.  Without going into the math, if you draw 120 watts continuously, at 10amps, this might last three hours, possibly eight hours on a deep-cycle marine type battery.  But then you have to recharge the battery.

The reason I mention that is, some will opt for a portable generator for most of the daytime duties of a power outage, then run a couple of lights at night off of an inverter.  You can run a couple of 15 watt bulbs (2.5 amps) for about 12 hours on a car battery.

In addition, your car’s alternator can generally only supply 700 watts.  So to run more than a 300watt inverter from a car, you’ll need to connect it directly to the car’s battery with cables, and then you will need to run the car’s engine continuously.  So that’s where a gas powered portable generator makes sense.

So why not use the inverter to power anything it can? Then when the batteries are depleted, or you need large loads to turn on, run a standard generator for a long time (at least an hour) to power the heavier loads.  Meanwhile let the battery charger then re-charge the battery to give the inverter its efficient power once you’re ready to shut the generator down. This one-two punch allows the most efficient use of fuel (only using a pollutant when you’re getting the most effectiveness out of your fuel).  You’ll run the noisier generator less,  and equally important, you’ll save money since you’ll use less fuel for the same used kilowatt hours.

It may take some math and some planning, but you can partner a good inverter with a small generator and reap the benefits of a light-weight, highly efficient, usable system.

What is an Inverter Generator?

what is an inverter generator Honda

Honda

Both common portable generators and portable inverter generators use fossil fuels to run an internal combustion engine.

Generators convert mechanical energy to electricity through to a phenomenon called electromagnetic induction.  Voltage is induced by the movement of a conductor, typically coils of wire, inside a magnetic casing.

In a conventional generator, each engine rotation produces one block wave of AC power. For the electricity to produce the standard 120-volt, 60-Hz electricity commonly used in the US, the engine must run at a constant speed of 3,600 rpm, regardless of the load, or how much electrical power you ask of it.

But a decade ago, Honda introduced a new type of machine known as an inverter generator.   It was smaller, lighter, quieter and more efficient than conventional models.

An inverter generator is designed to produce more AC electrical energy per engine rotation but not in a form that can be used directly  The raw electricity must first be transformed into DC power.   See the article on this site explaining DC (direct current) and AC (alternating current).  Basically you get DC from a battery and AC from your wall outlets.

An electronic inverter module then turns the DC power back into standard 120-volt, 60-Hz AC power.  The resultant AC is no longer in block waves but in sine waves.  This is measured in Total Harmonic Distortion (THD).  To be safe with your microprocessor enabled electronics, the THD should be less than 6%.  Inverter generators accomplish this whereas standard portable generators run in 9% or more THD..  This power from inverter generators is ultra-clean and in a form that can now be used in sensitive electronic equipment like medical devices.

In an inverter generator, the engine speed varies depending on the electrical demand being asked of it, which significantly reduces noise and fuel consumption compared to a standard portable generator. The end result is a portable generator with reduced weight and size, and power that is ultra-clean.

Drawbacks of Common Portable Generators

One of the major drawbacks of a standard portable generator is they can be terribly inefficient and waste a lot of fuel if they’re not used at full (or at least heavy) load for a long period of time.

They can unnecessarily pollute the environment for a small benefit when not being used at or near its capacity.   For example, running a 4,000 watt generator to run a light bulb at 100 watts, you waste fuel running that big engine for little benefit.   Remember a continuous 3,600 RPM?

Additionally, common generators are heavy and don’t surge very well.  So they are often over-sized to meet load demands.  The larger, heavier generators are used so there is an available large surge capacity, necessary for the starting watts needed for an electric motor.  Otherwise during surge the generator would bog down.

Benefits of the Portable Inverter Generator

Hyundai What is an Inverter Generator

Hyundai

Inverter generators have some real advantages over conventional generators. First and foremost, they’re quiet.  Standard portable generators are infamous for the noise during operation.  Offending neighbors or fellow outdoor enthusiasts is always a concern.

In addition, these new units are a lot lighter and smaller: 1,000-watt inverter generators weigh about 30 pounds and are about the size of a small cooler.

Inverter generators are also about 20 percent more fuel efficient than regular generators. A typical 2,000-watt unit can run at its rated load for nearly four hours on a gallon of fuel.

And finally, inverter generators produce electricity that’s somewhat safer for sensitive electronic equipment, such as laptops.

You will however, pay more per available kilowatt in a portable inverter generator.  That is, a 2Kw inverter will cost you much more than a 2Kw standard generator. This hasn’t stopped consumers from making these nearly a must-have household appliance.  The portable 1000 watt inverter generator is becoming commonplace for those who see the value of portable power and understand the limitations of powering one device at a time.

Typical Uses of Inverter Generators

Generac what is an Inverter Generator

Generac

From the outset, inverter generators were marketed to the thousands of campers, hunters and fishermen who wanted to bring the comforts of home into the great outdoors, while being less cumbersome and quieter.

Think of the great outdoors.  You’re “roughing it” under the stars.  But for necessity, convenience and safety you have your cell phone with you, right?  The inverter generator will safely keep your phone charged.

They are popular in the construction industry because workers can power up at 7 a.m. or in a quiet zone without the rumble of a standard portable generator.  Inverter generators produce about the same level of noise as a normal conversation (50 to 60 dBA) — that’s quieter than a household vacuum cleaner. Conventional generators can be as noisy as 65 to 75 dBA (decibels), about as loud as a lawn mower or chain saw.

Features to Consider

Champion what is an Inverter Generator

Champion

Small differences in the design of various inverter generators can make a big difference in how easy they are to use and maintain, but also affect price.  Keep these factors in mind:

•Control panels on better units include a display that allows you to monitor voltage output, frequency (Hz) and hours of operation. They also include LEDs that warn of over-load conditions.

•Many units include controls that allow you to switch from automatic power saving to a power-boost mode when short surges of power are required.

•Weight and size depend largely upon watt output.  Depending on weight you may opt for some sort of wheel apparatus.

•Noise levels can vary from manufacturer to manufacturer, even for units with the same out-put. When evaluating noise, be sure you’re comparing apples to apples — especially in regard to how far the unit was placed from the sound-level meter and the load at which it was running.

•Some units include a battery-charging cable, a spark plug wrench and a generator cover. Units that are designed to connect with another generator (for twice the power) come with parallel cables.

The Bottom Line

Yamaha what is an Inverter Generator

Yamaha

Although inverter generators are less costly to operate than conventional generators, they are more expensive to purchase. A 2,000-watt inverter generator could cost between $600 to $1,200, whereas a conventional unit with similar capacity might cost as little as $200. Higher-capacity inverter generators get very pricey.

If you use your generator frequently, you will recoup some of that in fuel savings. But more important, generator noise will no longer be a nuisance to your neighbors or to you.

There are portable inverter generator reviews on the Generator Grader site.  Check out the handy table below to compare the popular portable inverter generators in the 2000 watt range.  They are available in less watts and available in more watts.  Less watts in the 300 to 1000 watt range have limited use.  More than 3000 watts are more versatile but you can expect to pay close to $2000 and more.  Ultimate versatility is achieved when the unit has parallel capability where you can hook two units together for nearly double the power, and still use them separately when you need.

Compare Portable Inverter Generators

Brand ModelEngineRunning Watts/
Surge Watts
OutletsDecibelsWeightRun Time
@ 1/4 - 1/2 Load
CARB
Compliant
PriceConsumer Rating
out of 5 stars
Earthquake IG800Wread review40 CC700/800(1) 120V 5-20R
(1) 12V DC
56218.2 hours
@ 1/4 load
Y$4.4 stars
ETQ IN2500I125 CC2200/2500(2) 120V 5-20R
GFCI
(1) 12V DC
60695.5 hours
@ 1/2 load
N$3.1 stars
Hyundai HY2000siHyundai125 CC2000/2200(2) 120V 5-20R
(1) 12V DC
64725.5 hours
@ 1/2 load
N$$3.8 stars
Generac 5793 iX2000Generac126 CC2000/2200(2) 120V 5-20R
(1) 12V DC
NA524.7 hours
@ 1/2 load
N$$2.7 stars
Champion 73536IChampionread review80 CC1700/2000
parallel capable
(2) 120V 5-20R
(1) 12V DC
53489 hours
@1/4 load
Y$$4.3 stars
Champion 75531iChampion 75531i main viewread review171cc2800/3100(2) 120V 5-20R
(1) 120V TT 5-20R
58838.5 hours
@1/4 load
Y$$4.5 stars
Westinghouse WH2000iXLTWestinghouse WH2000iXLT79 CC1800/2200
parallel capable
(2) 120V 5-20R
(1) 12V DC
NA4313 hours
@ 1/2 load
Y$$4.5 stars
Powerhouse PH2100RRi125 CC2000/2100(2) 120V 5-20R
(1) 12V DC
NA737.5 hours
@1/4 load
Y$$3.9 stars
Yamaha EU2000isYamaha EF2000iS front viewread review79 CC1600/2000
parallel capable
(2) 120V 5-20R
(1) 12V DC
524410 hours
@ 1/4 load
Y$$$4.8 stars
Honda EU2000iHonda98 CC1600/2000
parallel capable
(2) 120V 5-20R
(1) 12V DC
5346NAY$$$4.7 stars
WEN 56200iWEN 2000 Inverter79cc1600/2000
parallel capable
(2) 120V 5-20R
(1) 12V DC
(1)USB
NA484 hours
@1/2 load
Y$$4.7 stars
This table compare portable inverter generators in the more popular power range of 2000 watts. Some models have parallel ability to hook two units together to nearly double the watts. Decibel readings generally taken at less than full load.
$ = Less than $500; $$ = Less than $900; $$$ = more than $900

Filed under: Inverter Generators