It is necessary to have a little prior knowledge to start the construction and subsequent installation of solar panels. The reader should become familiar with the characteristics of the solar cells, the different types of solar panels, the types of existing inverters and If you also want to save or conserve the energy produced by solar panels, then you should also know about the different conservation methods (usually batteries).
In the same way that to use and take advantage of a car or any electrical device in your home, you do not need to know exactly the technical details of its manufacture, not even what parts it is made of, in the same way, the information that we are going to provide you in this document, although it is a bit technical, it is not really necessary for the construction and installation of solar panels, and even less so to take full advantage of it. If you are one of those people who is curious to know what is inside that box, here we will talk a little about different technical aspects of the use of solar energy to try to satisfy your curiosity a little.
Crystalline Silicon and Gallium arsenide are the typical choice of materials for the manufacture of solar cells. Gallium Arsenide crystals are created especially for photovoltaic use, while Silicon crystals are available in cheaper standard ingots produced primarily for industry consumption microelectronics.
Polycrystalline Silicon has a lower conversion efficiency, but is also lower in cost.
When exposed to direct sunlight, a 6cm diameter Silicon cell can produce a current of around 0.5 amps to 0.5 volts (equivalent to an average of 90 W/m², in a range of usually 50-150 W/m², depending on solar brightness and cell efficiency).
Gallium Arsenide is more effective than Silicon, but also more expensive.
Crystalline ingots are cut into wafer-thin discs, polished to eliminate possible cutting damage. Dopants (impurities added to modify conductive properties) are introduced into the wafers, and metallic conductors are deposited on each surface: a fine grid on the sunlight side and usually a flat sheet on the other.
Solar panels are built with these cells cut into appropriate shapes. To protect them from damage to the front surface caused by radiation or handling, they are encased in a glass cover and cemented onto a substrate (which can be a rigid panel or soft blanket). Electrical connections are made in series or parallel to determine the total output voltage.
The foundation and substrate must be thermally conductive since the cells heat up by absorbing infrared energy that is not converted into electricity. Since cell heating reduces operating efficiency, it is desirable to minimize it as much as possible. The resulting assemblies are called solar panels or solar groups.
A solar panel is a collection of solar cells. Although each solar cell provides a relatively small amount of power, many solar cells spread over a large area can provide enough power to be useful. To get the most power, the solar cells must be pointed directly at the sun.
Building Solar Panels
1. Make small photovoltaic panels so you can gain experience.
2. In most situations, make panels of 36 or 72 solar cells and connect them in series. 36 cells gives you approximately 17.5 or 18 volts, and 72 cells gives you twice as much. These panels are very useful, you will find many products that match their output in terms of power. For example, if you want to use a charge controller to store power in car or truck batteries, these charge controllers are typically available in 12 or 14 volts, which matches the voltage of your 18 or 36 volt solar panels since the voltage of your panels should be 1.5 times higher than the voltage of the battery you are trying to charge.
3.- Connect several panels in manageable groups that you can transport and install without danger of breaking them.
4.- If what you want is to connect the solar energy produced by the solar panels to the existing electrical network in your house, then you will require solar inverters.
5.- If you want to take full advantage of and conserve unused energy for future use, then you should also consider using batteries as a method of energy conservation. Maybe you should then learn a little about the different types of batteries on the market. The most common for these cases are batteries for maritime use or for trucks. But this is not mandatory, in fact any car battery is used for this purpose.
If you want to become a serious panel designer, you should buy a good soldering iron that has adjustable temperature. Remember that this is one of the most important tools for building solar panels.
Basic specifications of a photovoltaic panel
Power: 60 Watts
Voltage: 16.8 Volts
Current: 3.56 amps.
Dimensions: 30 x 36 inches.