# Sticky  Solar Panels what to look for



## Hardy Solar

Solar Cells

* Monocrystalline - made from a single large crystal, cut from ingots. Most efficient, but also the most expensive. Somewhat better in low light conditions (but not as good as some advertising hype would have you believe).
* Polycrystalline - basically, cast blocks of silicon which may contain many small crystals. This is probably the most common type right now. Slightly less efficient than single crystal, but once set into a frame with 35 or so other cells, the actual difference in watts per square foot is not much.
* Amorphous - "thin film", here the silicon is spread directly on large plates, usually of something like stainless steel. Cheaper to produce, but often much less efficient, which means larger panels for the same power. Unisolar is one example.
* Vaporware - this is the 4th type - the one that pops up in the news about every 3 months, proclaiming the next major breakthrough that will make plastic spray on solar cells that will cost around 5 cents a watt, or some similar claim. Well, after almost 30 years in this business, we are still waiting for one of those to actually reach production, and I suspect we will be waiting for another 30.









For all practical purposes, how the three types work in applications is very similar. What is important when buying panels is to choose the right panel based on how much power you need, how much room you have, and where they will be mounted. They will all do the same thing - make electricity when the sun hits them. Thin film are often less efficient, so will take up more room for the same power, but on the other hand they work better in hot climates due to not losing quite as much at high temperatures.

You will see some manufacturers and websites claiming that panel XX is better because it is more efficient at low light. While it is true that monocrystalline ARE better, the difference in average daily production is less than 1%. If you have low light, you also have low sun energy. So converting 15% of very little is not much better than converting 14% of very little. So, yes, it is true, but about #18 on the list of things to worry about when buying solar panels.

A solar cell or a " photovoltaic" cell, is a device that converts photons from the sun into electricity. In general, a solar cell that includes both solar and non-solar sources of light (such as photons from incandescent bulbs) is termed a photovoltaic cell. Fundamentally, the device needs to fulfill only two functions: photo generation of charge carriers (electrons and holes) in a light-absorbing material, and separation of the charge carriers to a conductive contact that will transmit the electricity. This conversion is called the photovoltaic effect, and the field of research related to solar cells is known as photovoltaics.

Solar cells have many applications. Historically solar cells have been used in situations where electrical power from the grid is unavailable, such as in remote area power systems, Earth orbiting satellites, consumer systems, e.g. handheld calculators or wrist watches, remote radiotelephones and water pumping applications. Recently solar cells are particularly used in assemblies of solar modules (photovoltaic arrays) connected to the electricity grid through an inverter, often in combination with a net metering arrangement.

Solar cells are regarded as one of the key technologies towards a sustainable energy supply.
Three generations of development
First

The first generation photovoltaic, consists of a large-area, single layer p-n junction diode, which is capable of generating usable electrical energy from light sources with the wavelengths of solar light. These cells are typically made using silicon wafer. First generation photovoltaic cells (also known as silicon wafer-based solar cells) are the dominant technology in the commercial production of solar cells, accounting for more than 86% of the solar cell market.
Second

The second generation of photovoltaic materials is based on the use of thin-film deposits of semiconductors. These devices were initially designed to be high-efficiency, multiple junction photovoltaic cells. Later, the advantage of using a thin-film of material was noted, reducing the mass of material required for cell design. This contributed to a prediction of greatly reduced costs for thin film solar cells. Currently there are different technologies /semiconductor materials under investigation or in mass production, such as amorphous silicon, poly-crystalline silicon, micro-crystalline silicon, cadmium telluride, copper indium selenide /sulfide. Typically, the efficiencies of thin-film solar cells are lower compared to bulk silicon (wafer-based) solar cells, but manufacturing costs are also lower, so that a lower price in terms of $/watt of electrical output can be achieved. Another advantage of the reduced mass is that less support is needed when placing panels on rooftops and it allows fitting panels on light materials or flexible materials, even textiles.
Third

Third generation photovoltaics are very different from the other two, broadly defined as semiconductor devices which do not rely on a traditional p-n junction to separate photogenerated charge carriers. These new devices include photoelectrochemical cells, Polymer solar cells, and nanocrystal solar cells. 

History

The term "photovoltaic" comes from the Greek Word meaning "light", and the name of the Italian physicist Volta, after whom the volt (and consequently voltage) are named. It means literally of light and electricity.

he photovoltaic effect was first recognized in 1839 by French physicist Alexandre-Edmond Becquerel. However, it was not until 1883 that the first solar cell was built, by Charles Fritts, who coated the semiconductor selenium with an extremely thin layer of gold to form the junctions. The device was only around 1% efficient. Russell Ohl patented the modern solar cell in 1946. Sven Ason Berglund had a prior patent concerning methods of increasing the capacity of photosensitive cells. The modern age of solar power technology arrived in 1954 when Bell Laboratories, experimenting with semiconductors, accidentally found that silicon doped with certain impurities was very sensitive to light.

This resulted in the production of the first practical solar cells with a sunlight energy conversion efficiency of around 6 percent. This milestone created interest in producing and launching a geostationary communications satellite by providing a viable power supply. Russia launched the first artificial satellite in 1957, and the United States' first artificial satellite was launched in 1958. Russian Sputnik 3, launched on 15 May 1957, was the first satellite to use solar arrays. This was a crucial development which diverted funding from several governments into research for improved solar cells.
Applications and implementation

Solar cells are often electrically connected and encapsulated as a module. PV modules often have a sheet of glass on the front (sun up) side with a resin barrier behind, allowing light to pass while protecting the semiconductor wafers from the elements. Solar cells are also usually connected in series in modules, creating an additive voltage. Connecting cells in parallel will yield a higher amperage. Modules are then interconnected, in series or parallel, or both, to create an array with the desired peak DC voltage and amperage

Photovoltaics, or PV for short, is a Solar Power technology that uses Solar Photvoltaics system or Solar cell to provide electricity for human activities. Photovoltaics is also the field of study relating to this technology.










Solar Atlas

Solar cells produce Direct current electricity from the sunâs rays, which can be used to power equipment or to recharge a battery. Many Pocket calculator incorporate a solar cell.

When more power is required than a single cell can deliver, cells are generally grouped together to form âPV modulesâ that may in turn be arranged in âsolar arraysâ which are sometimes ambiguously referred to as Solar Panels. Such solar arrays have been used to power orbiting Satellites and other spacecraft and in remote areas as a source of power for applications such as roadside emergency telephones, Remote sensing, and cathodic protection of Pipe lines . The continual decline of manufacturing costs (dropping at 3 to 5% a year in recent years) is expanding the range of cost-effective uses including road signs, home power generation and even grid-connected electricity generation.
http://www.hardysolar.com/shop/home.php?cat=37


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## Ross

Great info thanks for going to the trouble. As suggested by a member I'm going to stick this to the top for now and build an informational directory later to move it to. Thanks again Hardy!


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## michiganfarmer

Thanks Ross. Im getting more interested in solar all th etime


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## YounGrey

Anyone know anything about rebates?


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## haypoint

Solar Ovanics is gearing up their production, made in Michigan. Currently most of their products go to Europe, where their are healthy government rebates. Two types that I know they make: a thin metal sheet that can be rolled out onto a metal roof and a panel that looks like a regular shingle that can be nailed onto the roof.


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## Rose_Thorn

i love solar power myself!!! its clean and effective!!! I made a few science models when i was back in school. but i didnt know there was that many different kinds of solar panels out there thx for that info Hardy Solar!!!!!


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## fillycate

We are thinking about solar, but we live in rainy Oregon and are wondering how effective it would be considering the cost involved. Any thoughts on that?


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## GreenheadRecycl

Anyone have the Harbor Freight planels?
Good? Bad? I would like to keep a 12 volt batt charged for a small water pump.


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## GreenheadRecycl

Anyone have the Harbor Freight planels?
Good? Bad? I would like to keep a 12 volt batt charged for a small water pump.
It's a start...


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## GreenheadRecycl

Anyone have the Harbor Freight planels?
Good? Bad? I would like to keep a 12 volt batt charged for a small water pump.
It's a start...


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