Learn About Solar Modules
What is a solar cell ?
A solar cell or photovoltaic cell is made of special materials called semiconductors, the most common semiconductor material which is used in the manufacture of a solar cell is known as silicon. When a light source strikes a solar cell, a portion of it is absorbed by the semiconductor material. The absorbed light energy knocks electrons loose, allowing them to flow freely. See illustration
Ordinarily pure silicon is a poor conductor of electricity so impurities such as phosphorus and boron are added to create what is known as a semi-conductor. The addition of these impurities not only allows the silicon to conduct electricity, but also acts to force electrons freed by light absorption to flow in a certain direction. This directional flow of electrons is also referred to as a current. By placing metal contacts on the top and bottom of the solar cell, it then becomes possible to draw that current off to use externally to perform work.
What is a solar electric module ?
A solar electric module consists of an aluminum framed sheet of highly durable low reflective, tempered glass that has had individual solar cells adhered to the inner glass surface. These individual solar cells are wired together in a series parallel configuration so as to obtain the necessary voltage and current.
Individual cells are wired in series strings to increase the module's voltage and the series strings are wired in parallel to increase the module's current. The back of the module is protected by another sheet of tempered glass or a long lasting material such as Tedlar.
The series parallel connections are passed through the protective backing and then wired to a weather proof junction box which is permanently mounted to the back of the module. The junction box is where the module's output connections are made.
Several solar modules wired together are known as a solar panel.
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What is the difference between monocrystalline and polycrystalline cells ?
There are two cell technologies that are prevalent in today's market, they are referred to as polycrystalline and monocrystalline silicon. Some manufacturers will use one or the other technologies in the manufacture of their product some will use use both.
Solar cells that are created from monocrystalline or (single crystal) technology are cut from a silicon boule that is grown from a single crystal, in other words a crystal that has grown in only one plane or (one direction). Single crystalline are more expensive to manufacture and typically have a slightly higher efficiency than do conventional polycrystalline cells resulting in smaller individual cells and thus typically a slightly smaller module.
Solar cells that are created from polycrystalline or (multicrystalline) technology are cut from a silicon boule that is grown from multifaceted crystalline material, or a crystal that grows in multiple directions. Conventional multicrystalline solar cells typically have a slightly lower efficiency resulting in larger individual cells and thus typically a slightly larger module. All of this has changed with the advent of the new silicon nitride multicrystalline cells which are rated as high or even higher efficiency than similarly sized monocrystalline cells.
It's important to keep in mind that a 100 watt module is a 100 watt module whether it was made from polycrystalline cells or monocrystalline cells.
What about Amorphous technology
Amorphous or thin film technology has for years been touted as the technology of the future that would offer a reduction in the cost of manufacturing solar modules. Many companies have entered and promptly exited the market with little success. Thin film or Amorphous technology has a lower efficiency rating so thus panels that are manufactured from this process tend to be substantially larger in size requiring a greater roof area for a typical installation. Questions concerning life expectancy remain unanswered.
This is from
HEREand may answer the question about the shading effect described below information on different types of solar panels. I hope this helps in the understanding between the differences and types of SOLAR PANELS available.
It is extremely important that all the solar panels in a system are free from shading during the daylight hours. Even the partial shading of one cell in a panel will lower its power output. As the cells of a panel are connected in series the weakest cell will bring the others down to its lowered power level, which can reduce the efficiency of the whole panel by as much as fifty percent.
Found
HERE.
Pat
on some ( 4 ) 7 Amp Hr Gel-cells + 14 Amp Hr Gel Cell.
by ARKPAT » Tue May 19, 2009 7:36 pm 
