A POWER INVERTER converts your DC (direct-current) battery voltage into 120 volt and/or 240 volt AC (alternating current) electricity that is suitable to power common household lights and appliances.  This enables you to have a fairly "normal" solar power household with regard to the electrical appliances you use.  Of course there are still a few areas that require unconventional choices, such as refrigeration, because the conventional versions of these appliances aren't very efficient and waste a lot of your precious electricity.  See the Refrigeration page for more info.
    Back to the subject of inverters, they can easily be divided into two main groups: sine-wave, and modified sine-wave.  That refers to the shape of the alternating current wave form.  A sine-wave is the sort of power you get from the electric company.  On a graph it looks like a smooth and even mountain that rises above the zero line, and then dips in a mirror-image below the line.  This is cycle is alternating endlessly, the voltage rising smoothly to a rounded peak on the positive side of zero, and dipping to an identical upside-down peak on the negative side of zero, 60 times each second.  This produces a frequency of 60 cycles per second, or 60 Hertz, which is the standard here in North America.  
    By contrast, a modified sinewave does the same thing but in a series of small steps.  It looks like a staircase that rises to the top of the mountain and then descends down the slope again to it's mirror-image negative counterpart.  It also operates at 60 Hertz (Hz).  Maybe you don't really care about the shape of the waveform, but some appliances do.  Audio equipment will usually produce a low hum that is noticeable at low volumes, and it often interferes with AM radio reception.  The electronics in some appliances will not operate properly on modified sine-wave power.  Light dimmers may not work, or may burn out prematurely.  Electric clocks will not keep correct time.  Most things will work just fine, but it is hard to know without actual trial.  Some devices will fail.  The speed control circuitry of my wife's treadmill is completely confused by modified sine-wave.  That said, I used modified sine-wave for many years and didn't find it to be too much of a hassle.  With the current progress in inverter technology, modified sinewave inverters are becoming more scarce in the market.

Finally, you should know that most modern inverters incorporate a battery charger into their design.  That means, when you start a generator, or connect to grid power (for those who use the inverter for a utility power back-up system), the inverter automatically stops producing inverter power and begins to charge your batteries.  At the same instant, it transfers power from the generator to your home so you are then using electricity directly from the generator.  This all happens in a tiny fraction of a second, and the lights in your home may make a tiny flicker.  In my experience, the power transfer doesn't interrupt anything, not even a computer.  For example, your batteries are down to 50% charge after a series of cloudy days, and you need to do laundry.  Start your generator, and the batteries begin to charge from generator power while everything in your home is receiving direct generator power.  This makes the most efficient use of your generator and its fuel consumption.  It gives you a charging alternative when your energy consumption exceeds solar production, or to power heavy loads that exceed the capacity of your inverter.  You should always use a battery temperature sensor with your inverter to make sure that your batteries are charged efficiently  as their temperature changes.

Most inverters can be "stacked" (2 units connected together) to provide split 120/240 volt output to connect directly to your your home's electrical panel and power 240 volt loads like a deep well pump, just like the utility power would.  The same thing can be achieved with one inverter and an optional transformer, but the power output is limited to that of the single inverter.  Outback has a stacked configuration that provides the greatest 120/240 load flexibility, but the details are beyond the scope of this explanation.  Most of the inverters shown below can be purchased already pre-assembled and pre-wired into the appropriate circuit breaker enclosures as a finished unit (Power Center) to make installation fast, neat and easy.  Or, you can buy the enclosures and circuit breakers and do the wiring yourself.  Here is an excellent article about choosing an inverter.

MAGNUM ENERGY inverter/chargers are the first on my list simply because they are a solid product at an affordable price, that is still made in the USA.  Outback and Xantrex are well known, but most of their products are imported.  You decide if that matters or not.  Magnum is a high quality inverter at an excellent price.  Automatic generator start controls are available.  Some Magnum models offer 120/240 output without a  transformer or the need for stacking two inverters, which is perfect for smaller systems using 120/240 backup generators.  FREE SHIPPING on Magnum inverters to the lower 48 states only (not HI or AK). MS series has 2-YEAR warranty.

Magnum inverter/chargers employ a sophisticated 5-stage battery charger with temperature-compensated output.  Unlike many competitive models, Magnum saves you money by including the temperature sensor with the inverter.  Most Magnum inverters have search capability, which allows them to go into an "idle" mode when not being used.  Much like Outback, Magnum Inverters require an optional remote control panel to program the inverter... MERC50 remote ..... $150.  The Magnum BMK battery monitor kit cleverly converts the Remote display into a deluxe system monitoring device that gives you important data about your battery status and state-of-charge.  You get all the information you need on a single display!  Magnum BMK ..... $125.  The MERC50 remote is free with purchase of a pre-wired power center (free shipping does not apply to power centers).

	Magnum Energy Inverters With over 70 years of design and manufacturing experience, Magnum Energy of Everett, Washington is producing highly reliable and advanced inverter/chargers.
Magnum Inverter Model	Part Number	Output Power	Battery charger output AMPS	Type & Application	Price	Compatible w this Epanel Model
Free Shipping on all Magnum inverters for continental U.S. only, not Hawaii or Alaska NOTE: Any of these Magnum Energy Inverters can be pre-wired into a Midnite Solar EPanel for savings of installation time and cost.
MS Series Pure Sine Wave Inverter/Charger                       ***SALE PRICES!***
MagnaSine MS-4448AE / 240	2944842	4400 watts	60 Amps @ 48V	Sinewave / OffGrid 120 / 240 volts	$2160	MNE175STM/240-L
MagnaSine MS-2012	2920121	2000 watts	100 Amps @ 12V	Sinewave / Mobile / OffGrid	$1600	MNE250STM
MagnaSine MS-2812	2928121	2800 watts	125 Amps @ 12V	Sinewave / Mobile / OffGrid	$1840
MagnaSine MS-4024	2940241	4000 watts	100 Amps @ 24V	Sinewave / Mobile / OffGrid	$2080
MagnaSine MS-4024AE / 240	2940242	4000 watts	105 Amps @ 24V	Sinewave / OffGrid 120 / 240 volts	$2160
ME Series Inverter/Charger
Magnum ME-2012	2920120	2000 watts	100 Amps @ 12V	Modified Sinewave / Mobile / OffGrid	$1125
Magnum ME-2512	2925120	2500 watts	120 Amps @ 12V	Modified Sinewave / Mobile / OffGrid	$1280
Magnum ME-3112	2931120	3100 watts	140 Amps @ 12V	Modified Sinewave / Mobile / OffGrid	$1,480
RD Series Inverter/Charger
Magnum RD-3924	2939240	3900 watts	105 Amps @24V	Modified Sinewave / OffGrid	$1540
Magnum RD-2824	2928240	2800 watts	80 Amps @24V	Modified Sinewave / OffGrid	$1350	MNE175STM
Magnum RD-1824	2918240	1800 watts	50 Amps @24V	Modified Sinewave / OffGrid	$1040	MNE125LT
MM Series Inverter/Charger
Magnum MM-1212	2912121	1200 watts	70 Amps @ 12V	Modified Sinewave / Mobile	$720
Magnum MM-1524AE	2915240	1500 watts	35 Amps @ 24V	Modified Sinewave / OffGrid	$755
Magnum MMS-1012	2901242	1000 watts	50 Amps @12V	Sinewave / Mobile	$960
Magnum MM-612AE	2906120	600 watts	30 Amps @ 12V	Modified Sinewave / OffGrid	$480	MNDC125

OUTBACK POWER SYSTEMS offers several models of sinewave inverter/chargers including mobile use, grid-tie, and completely sealed units for use in challenging environments.  Outback inverters are designed in the USA.  Multiple units can be connected in series to provide increased power output at the same voltage (120 volts), or in parallel for 120/240 operation.  Several other configurations are possible depending on application requirements, giving excellent versatility.  Outback inverters are available as pre-assembled Power Centers at a very attractive price, making installation easy and very clean looking.  Inverters require the use of a MATE controller for programming ..... $235.  The MATE can also control and monitor Outback charge controllers, all from a remote location.  Add a Flexnet DC adapter and your Mate  also becomes a sophisticated battery monitor that displays accurate voltage, current, and state-of-charge ..... $300.

XANTREX (formerly known as Trace) is one of the big-hitters in the inverter market, with a huge product line from industrial "solar farm" products to "cigarette lighter" inverters for use in your car.  Below you'll find the models most relevant to off-grid and grid-tie use.  China.

PROSINE is a Xantrex brand sinewave inverter built primarily for use in RVs, boats, and vehicles (mobile use), although it can work in a stationary application as well.    The 2000 watt and 3000 watt models have a built-in battery charger and transfer relay, and battery temperature sensor and remote control panel are included.  The the smaller models do not have a charger and do not include the accessories.  The HW models use hardwire connection to your power distribution system, while the GFI models include a Ground Fault Interrupter outlet for enhanced safety.  China.

EXELTECHoffers a line of high-quality, small-output sinewave inverters.  Their waveform is held to very strict tolerances to provide extremely "clean" power for sensitive applications such as professional audio recording, where induced noise is unacceptable.  These inverters are quiet and do not buzz. If you want the best, this is your choice.  Average lifespan exceeds 20 years, with 1 year parts and labor warranty.  These units do not have an internal battery charger.  Made entirely in the USA.  Exceltech provides inverters to the US military, and Exceltech inverters are in use for communications backup power at every US embassy worldwide.  That's how good they are.

SAMLEX represents the budget end of the inverter spectrum.  This is the choice when economy is the primary concern, particularly when a smaller inverter is needed for a mobile or portable application.  TN model has a built-in charge controller. The larger models also have battery charging capability.   Samlex units are imported.

INVERTER CABLES

You need the right cables to safely connect your inverter.  Using improper size or type of wire can reduce performance and void your inverter's warranty.  I offer highly flexible, heavy-duty welding cable with flat lug ends for easy connection.  Contact me for help in choosing the right size for your needs.

#2 copper, 10 feet long, 3/8" bolt hole, (pair)  ..... $70
#2/0 copper, 10 feet long, 3/8" bolt hole, (pair)  ..... $95
#4/0 copper, 10 feet long, 3/8" bolt hole, (pair)  ..... $140