Solar panels work by converting sunlight into electricity. The science behind this conversion is known as photovoltaic technology. Photovoltaic Cells or solar cells as they are more commonly referred to are the major components of any residential solar power system.
Photovoltaic (PV) produces electricity directly from the electrons that are freed when sunlight hits the surface of the PV cell and interacts with the semiconductor material in the PV cell. These cells are wired together to form a PV module, which is the smallest PV component sold commercially. The PV modules range in power from 10 watts to 300 watts.
The raw material for the solar panel is silica (sand). The manufacturing process removes all of the impurities and defects, and results in a solar-grade silica feed stock. From there the silica is coated with Boron or Phosphorus to tweak the frequencies of light silica responds to.
When sunlight hits the solar cell with enough energy the photons in the light knock electrons free in the silicon crystalline structure forcing them through an external circuit or Direct DC Load and then returning them to the other side of the Solar Panel to start the process all over again (thus the renewal source).
The flow of freed electrons results in a voltage output of approximately 0.5v per single crystalline solar cell. The Amperage output is directly proportional to the cells surface area - about 7amps for a 6 inch square solar cell. Typically you will see 30 to 36 cells wired in series or in parallel with other solar modules to from a complete solar array to charge your battery bank, within your solar power system.
The PV module produces direct current (DC) but your home uses alternating current (AC). Therefore, solar panels require that we include a converter in the system to convert the DC current to AC current. This is accomplished with an inverter, a special piece of equipment that converts or changes DC electricity to AC.
Once the solar array (the collection of solar panels wired together in your solar power system) starts producing electricity you can use the electrical power, store it for later use or sell it back to your local utility if your system is connected to the grid. Selling back to the utility is referred to net-metering.
As more and more homes convert to solar power we can expect to see major improvements in the efficiency of solar cells just as we experienced improvements in gas mileage in cars with carburetors, fuel injection, etc.
In order to store the unused electricity for later use, you will need to incorporate batteries into the solar power system. These batteries serve the same purpose as the batteries in a car. Every time you start your car, the ignition is utilizing the stored electrical power in the battery to turn over the starter motor. Have you ever tried to start your car and nothing happens? If the starter is working properly, you know that the battery is dead and there is no electrical current available to power the starter which in turn starts the motor.
Solar batteries store the excess PV electricity until it is needed at a later time to run your appliance or the lights, etc. Once the batteries are fully charged you need to turn off any incoming power or they will be damaged. The solar batteries are DC just as the battery in your car. This means the batteries will be installed in your solar system between the Photovoltaic Cells and the inverter.
Note: You will be better off purchasing the best deep cycle batteries you can afford. Industrial deep cycle batteries can cost $200 each, but have a life expectancy of 5-8 years. Your car battery will only last 1 year in deep cycle applications.
It is worth noting that even though lead acid batteries are not environmentally friendly; the alternative of relying on fossil fuels is a poorer choice.
Blog