Advice on Solar Inverters

8/3/2019 Advice on Solar Inverters

1/17

Advice on Solar InvertersBy Diane Bacher , eHow Contributor

y

y

y

y Print this article

Solar inverters are necessary to convert the DC electricitygenerated through your solar panel system to AC electricitythat's used by the national grid. The distinction between DCand AC electricity is that DC has a current that runs in onedirection along a circuit; AC has a current that can cycleboth ways along a current (the current can run in reversebut alternates in a consistent pattern that looks like a wavewhen graphically depicted).

There are two different types of inverters that address thewave patterns produced by alternating current.

Related Searches:y Grid Solar Invertery AC Power Inverter

1. Solar Power Inverters

o Any inverter you choose for your solar panel system willhave to be compatible with your battery bank and householdelectricity requirements. Voltage is the predeterminingfactor. Battery banks are either 12 or 24 volt. Your invertermust be compatible with that input voltage.


2/17

The difference between solar power inverters lies in the sinewave characteristics of the alternating current produced. Asine wave looks like a symmetrical coil lying horizontally.

2. True Sine-Wave Inverterso True sine-wave inverters are consistent with or better than

the electricity produced by public utility companies: The sinewave produced is truly a consistent pattern. These types ofconverters are more expensive because they rely on moresophisticated technology to produce electricity with

appropriate voltage for household use. The switches andtransformers relay alternative current to step up (that is,convert) the direct current from your batteries to analternating but consistent current at increased voltage.

Modified Sine-Wave Inverters (SquareWave)

o A modified sine-wave inverter can be used for your solarpower system but is not recommended to run any medicalequipment and is really not consistently good for running anentire household's electrical loads. Modified sine waves lacksteps in the switch transformer technology but will producecurrents with a majority of symmetrical waves. However,there are dead spots within the wave cycles; these dead

spots create distortion, which creates poor-quality electricitythat can harm high-quality electronics.

If you're going to rely on your solar power for as muchelectricity that can be generated, invest in a true sine-waveinverter.


3/17

Sponsored Links

y 220v power inverterAPCIndiaStore.com

Power Cuts Interrupting the Best Cricket Moments? Get an APC

UPS!

y Inverters Tirunelveligetit.in/Inverters-Dealers-44444444

Dealers & Suppliers of Inverters in Tirunelveli. Find now.

y inverter best dealer inwww.manthraups.com

chennai all brands available call mr b.manthiram 9840454293

y UPS Battery companywww.VoltaProduct.com/Battery

Efficient and reliable ISO 9001::2000 certified UPS BatteryCompany

Read more: Advice on Solar Inverters |

eHow.comhttp://www.ehow.com/way_5793341_advice-solar-

inverters.html#ixzz2JmI8VcFT

Inverter has become a necessity than a luxury with

frequent power cuts. People now want to run all

home appliances including air conditioners,

televisions and refrigerators for their convenience.

A power inverter converts 12V DC power to

standard household 230V AC power, which allows

INVETER BRANDS

Genus

Su-Kam


4/17

you to run AC electrical equipment in case of

emergencies or simple convenience.

TYPICAL USES OF

INVERTERSInverters normally have one or more standard

outlets to power laptops, small-screen TVs, video

game players or portable DVD players and other

devices. A DC to AC power inverter is great for

camping at parks that do not provide electricity. The

toaster, blender, and boom box can all still be used.

FEATURES OF INVERTERS

Ground Fault Protection

Inverters that have built-in GFCI protection are

advised for powering portable electrical devices

specially if used outside the house. Ground

faultprotection is a feature that instantly turns off

the inverter if it gets damp or wet. The inverter then

resets, senses the conditions and turns itself back on

if the problems have been resolved. The GFCI

feature protects the user from electrical shocks and

the potential risk of a fire.

Transfer Switch

Some power inverters have a built-in transfer switch

so you can switch from inverter power to utility

power when available. The transfer switch allows

external power to be transferred to appliances

automatically. Typically this feature is found onmore expensive high-end inverters.

Luminous

Birla Power

Dynamic

Prolite

Videocon

Usha Zentra

Unitron

Hykon

APC

Microtek

True Power

Unique Max

COMPARE

INVERTER PRICE

AND FEATURES

PriceIndia

Naaptol

Shopmania

eBay

INVERTER


5/17

REVIEWS

Mouthshut

India Review Channel

Solar Power Support

A power inverter is also an essential part of a solar power system. It converts the DC

power generated by solar panels and stored in 12V batteries to 230V AC power

suitable for household or industrial use. These systems can be costly, as they often

involve additional electrical work and equipment to incorporate the system into a

household's current electrical system.

POWER INVERTER OR GENERATOR?

Whether to use an inverter or a generator depends on the type of load and how

often you will need emergency AC power. Generally, an inverter is more economical

power alternative to run items under 1000W, suitable for small appliances, TVs,

VCRs, DVD players and other low load devices. If you plan to operate a refrigerator,

freezer, washer, dryer or well system, then a generator is a better choice. If your

planned power consumption exceeds 2000W, you should choose a generator, as thedraw in the battery will rapidly deplete its power.

HOME APPLIANCE POWER USAGE

The typical usage of power appliances which you can use for approximate

calculations is as in the table below ( do check the actual appliances wattage for

caculating wattage):

Appliance Power (in Watts) Starting (in Watts)

Fan 100 200

Tubelight 50 100


6/17

TV 120 240

Laptop 75 100

Washing machine - with heater 1200 2400

Washing machine - without heater 2000 3200

Air Conditioner (1.5T) 2200 4000

Air Cooler 1000 2000

Refrigerator (150W) 150 300

CHOOSING THE RIGHT INVERTER SIZE

Power inverters come in many sizes, measured in watts (W). The amount of wattage

you will require depends on the total draw of the devices you'd like to use.

Many appliances and power tools have their wattage rating indicated on the product

itself. Wattage rating can also be calculated by using this formula:

Volts x Amps = Watts

To determine if several appliances can be operated at the same time, simply add up

their wattage ratings to see if the total falls within the specifications of the power

inverter. For example, if you have a two-outlet inverter and will be plugging in 2

devices at once, add up the total wattage of both devices, then add at least 50%

more to account for peaks or spikes in the power draw. For example if your DVD

player draws 100W and your laptop another 100W, a minimum 300W inverter

((100W + 100W) x 150% = 300W) is recommended.

Make sure the power of the inverter is listed as "continuous". Some inverters arelisted at a certain wattage, but can only draw that wattage for a short period of time

(i.e.: 5 minutes) and then will shut off, reset themselves and resume functioning.

These outages can be frustrating to you and harmful to the device you are powering.

If the item is motor driven, it requires additional start-up (surge) wattage (typically 2-

3 times the continuous wattage required) to start the device. For example, a saw


7/17

that runs at 700W might require 1400W to start up. If your inverter only supplies

1000W, you will not be able to start it up. In this case, you would want to select an

inverter rated at least 1400W surge to handle start-up needs.

TYPES OF INVERTERS

Power inverters produce one of two different types of wave output:

y Modified Sine Wave

y True Sine Wave

Modified Sine Wave Inverter

Modified sine wave inverters deliver power that is consistent and efficient enough to

run most devices adequately. These types of inverters are the most popular and

affordable. They are also small and highly efficient. The Vector power inverter line is

based on modified sine wave technology.

True Sine Wave Inverter

True sine wave inverters are the most expensive, but they also deliver the most

consistent, highest quality wave output. Some sensitive equipment requires a truesine wave, like laptop computers, tool battery chargers, professional audio/video

equipment, certain medical devices and variable speed tools. If you aren't sure if the

device you want to use requires a true sine wave or not, call the manufacturer to

ask. Any AC device will run on a true sine wave inverter, whether it requires it or not.


8/17

Modified and True Sinewave Inverter Output

Advantages of True Sine Wave Inverter

y Output voltage wave form is pure sine wave with very low harmonic distortion

and clean power like utility-supplied electricity.

y Inductive loads like microwave ovens and motors run faster, quieter and

cooler.

y Reduces audible and electrical noise in fans, fluorescent lights, audio

amplifiers, TV, Game consoles, Fax, and answering machines.

y Prevents crashes in computers, weird print out, and glitches and noise in

monitors.

y Reliably powers the following devices that will normally not work with

modified sine wave inverters:

o Laser printers, photocopiers, magneto-optical hard drives

o Certain laptops and computers

o Some fluorescent lights with electronic ballasts

o Power tools employing "solid state" power or variable speed control

o Some battery chargers for cordless tools

o Some new furnaces and pellet stoves with microprocessor control

o Digital clocks with radioso Sewing machines with speed/microprocessor control


9/17

BATTERY BASICS FOR INVERTERS

See Inverter Battery Buying Guide - Brands, Price, Reviews, Models

SAFETY AND INSTALLATION TIPS FOR INVERTERS

Always use a power inverter that is rated high enough for the device(s) you are

running and avoid adapters that would allow more outlets than the unit is designed

to accommodate.

y Place the inverter on a reasonably flat surface, either horizontally or vertically.

y The inverter should not be installed in the engine compartment, due to

possible water/oil/acid contamination, and excessive heat under the hood, as

well as potential danger from gasoline fumes and the spark that an inverter

can occasionally produce. It's best to run battery cables to a dry, cool inverter

mounting location.

y Keep the inverter dry. Do not expose it to rain or moisture. DO NOT operate

the inverter if you, the inverter, the device being operated, or any othersurfaces that may come in contact with any power source are wet. Water and

many other liquids can conduct electricity which may lead to serious injury or

death.

y Avoid placing the inverter on or near heating vents, radiators or other sources

of heat. Do not place the inverter in direct sunlight. Ideal air temperature is

between 50 and 80 F.

y In order to properly disperse heat generated while the inverter is in operation,

keep it well ventilated. While in use, maintain several inches of clearance

around the top and sides of the inverter.

y Do not use the inverter near flammable materials. Do not place the inverter in

areas such as battery compartments where fumes or gases may accumulate.

y Inverters work best with a battery that is in good condition and fully charged.

A weak battery will be drained easily if demands are too high. This could leave

you stranded so be sure to check the battery's condition before using a power

inverter in a stationary vehicle.


10/17

y Make sure the inverter is properly ventilated. Even a small inverter generates

heat. Check to see if there is an internal fan with any inverter over 100 Watts.

Place the inverter in a well-ventilated area when in use.

y Check the owner's manual for the proper wire size for battery cables when

connecting the inverter to the battery. Most manufacturers recommend 4 to10 feet of cable length, depending on the inverter. Avoid aluminium wire

because it has higher resistance to current flow than copper wire.

Also,

y

Inverter Battery Buying Guide - Brands, Price, Reviews, Modelsy UPS Buying Guide - Brands, Price, Reviews

What is a power inverter?

The basic function of a solar powered inverter is to convert thedirect current to alternating current. Solar panels, and in factalmost all eco-friendly power sources such a wind turbines,generate direct current. But almost everything that makes up thefabric of civilization runs on alternating current. Current flows froma battery or solar cell in one direction, but an alternating currentstream reverses direction 60 times each second. While this mayseem wasteful, the detailed physics of the situation mean thealternating current can be sent over longer distances moreefficiently that direct current. Dont worry if the advantages of ACcurrent do not seem obvious - even Thomas Edison wasuncomfortable with alternating current! Suffice it to say that almostall the devices in your home; motors, appliances, televisions, usealternating current.


11/17

What is a grid tie power inverter?

The main difference between a standard power inverter and a gridtie power inverter is that the latter also ensures that the powersupplied will be in phase with grid power. This allows individualswith surplus power (wind, solar, etc) to sell the power back to theutility in the form of net metering or the arrangement your localutility offers.

On the AC side a grid tie inverter must supply electricity insinusoidal form, synchronized to the frequency of the grid andlimit the feed in voltage to no higher than the grid voltage. A gridtie inverter also must disconnect from the grid if the utility gridgoes down (blackout). In the event of a blackout, the grid tieinverter will shut down to prevent potentially harming the lineworkers who are sent to fix the power grid. See wikipedia article

on grid tie inverters.On the DC side, the power output of a module varies as a functionof the voltage in a way that power generation can be optimized byvarying the system voltage to find the 'maximum power point'.Most inverters therefore incorporate 'maximum power pointtracking' (MPPT).


12/17

How Solar Powered Inverters and AlternatingCurrent work

The alternating current we usually need to get from our solarpowered inverter needs to match the alternating current from ourelectrical utility. This current alternates because it is produced byrotating electrical generators. Current flows when a coil of wirepasses thru a magnetic field. Generators are designed to passcoils of wire thru a magnetic field as they spin, so the currentactually leaves, and then returns, to the power plant. As ithappens, by using alternating current, the system can bedesigned for higher voltage and lower current, allowing morepower to move thru the grid with less loss to heat.

Current is what causes energy to be wasted in powertransmission thru wire. To reduce this line drop loss, the voltageapplied at the power plant which drives this current can be ratherhigh. Along the way to your house, the voltage is dropped in aseries of transformers which can be thought of as big coils of wire,almost as a generator with no moving parts.

A solar powered inverter, like any inverter, converts steady directcurrent from a solar cell or battery to a smooth oscillating sinewave by switching the DC power on and off, very quickly. As arough cut, switching the DC power 60 times a second createswhat is called a square wave. But if we subtract out powerswitched 180 times a second we can round the corners of thesquare a bit. And by further switching in power at 300 and out at420 times a second an inverter can approach a smooth AC wave

quite closely. Some electrical components (capacitors andinductors) used on the AC Side of the inverter can store anddischarge a bit of power as the many square waves pass, furthersmoothing out the stack of square waves and approximate regularAC Power.


13/17

Why are solar inverters needed?

Solar panels generate DC electric power. Our home

appliances and lighting bulbs need AC power fortheir normal operation. The utility grid carries ACpower with precise characteristics into our homes(115V 60 Hz in the US). The solar inverter is an a

smart electronic device that converts the DC powergenerated by the solar panels into standard AC

power. Our appliances lighting bulbs and

entertainment electronic devices cant tell thedifference between the utility supplied power andthe inverter supplied power.

A piece of history; in the late years of the 19thcentury, there was a fierce battle between Edisonwho supported DC generators and Tesla whosupported AC generators. In the Chicago 1893

exposition, Tesla proved the superiority of AC powergeneration and AC power distribution. In those days,

electronic engineering was still in very early stage toprovide the engineering solutions we have today

What are the types of solarinverters?

Different application areas call for different typesof solar inverters. The three most importantapplication area are:


14/17

y Grid-tied inverters: solar inverters that areconnected to the utility grid and to the home supplyline. A grid tied inverter must have an automatic

shut-down mechanism (anti-islanding protection)during power outages. Since 1999, the standard foranti-islanding protection in the United States hasbeen UL 1741. Similar standardsexist in otherregions of the world

y Stand-alone (off-grid) inverters:off-grid solarinverters are not connected directly to the solarpanels. They are connected to a bank of deepcycle batteries. The batteries are charged through acharge controller by the solar panels.The batteries can be charged also by a small windturbine or by a micro-hydro (water stream) dam-lessturbine. The higher power versions ofthese inverters are used for off-grid homes (homes

not connected to the grid). Medium size and smallsize inverters are used to complement the RVsolarpanel, and for small boat solar systems.

y attery backup inverters: a less ubiquitous

application in which theinverter is designed to pull

charge from deep cycle batteries(controlled by acharge monitor) and supply the surplus electricalenergy to critical loads. These inverters are thereplacement of traditional diesel emergency back-upgenerators that provide power to selected loads(such as elevators and emergency lighting) during


15/17

utility power shutdown. These inverters are requiredto have anti-islanding protection per UL 1741

What is a pure sine waveinverter?

The utility supplies a well regulated AC power,115V 60 Hz in the US. The voltage follows analmost perfect sinusoidal waveform. Electricalappliances, especially those that have electricalmotors (refrigerators, washing machines, dishwashers, etc.) require for their optimalperformance that the supplied voltage will be apure sine wave. The pure sine wave inverter is

an electronic masterpiece that supply an almostperfect sine waveform electrical power at the

right voltage (115V in the US) and rightfrequency (60 Hz in the US).

There are other inverters on the market that arenot pure sine inverters; a cheaper inverterprovide a square waveform power, it is moreefficient, however only a limited types of home

electrical loads can be supplied from theseinverters. There is also a type called modified

sine wave inverter, the Total Harmonic

Distortion (THD) exceeds the 5% limit mostappliances could stand, therefore I don'trecommend to use the modified sine waveinverter to feed power to home appliances.


16/17

The important specifications of

solar pure sine wave inverters

What are the main specifications for a pure sinewave inverter you want to look into?

y DC voltage rating and the tolerance; you want anominal 12V (9-17VDC) inverter for 12V operation

y

Rated maximum input current

y Output AC Power: 120VAC, 60Hz (plus or minus0.4%) for the US; for most other countries, 230V50Hz

y Power capability in Watts (AC side) to fit your homeconsumption

y Power Surge capability in Watts to accommodatefor source (batteries or solar panels) voltagechanges and load current changes (when heavy load

such as a washing machines starts, a transition to ahigher current consumption causes a transient thatthe inverter must cope with)


17/17

y Efficiency - What percentage of DC power isactually converted to useful AC power? Look fornumbers around 92% or even exceeding 92%

y Over-current protection, over-temperature protection

and other protections

y Heat removal method (usually a fan)

y AC and DC circuit breakers, remote control (drycontacts) is a desired feature

y A smart controller and remote monitoring

y Compliance to UL 1741

y For pure sine wave inverter the purity is measuredby the harmonics; look for low harmonics contentmeasured by THD (Total Harmonics Distortion), lessthan 5%. (rings a bell? HiFi systems also have adistortion limit. With musical ear you can actuallyhear the higher harmonics of the 60Hz sound)

Documents

Advice on Solar Inverters