How to Use Solar Panels - Basic Tutorial for the Layman
PV cells connected in series to gain higher voltage levels
Understanding Solar Panels
A solar panel is a device which is able to convert solar energy or sun rays into electricity. It is basically made up of many photo voltaic cells connected in series electrically.
The photo voltaic cells or the PV cells are made up of a special semiconductor material which are very sensitive to photons or light rays and tend to get agitated in the presence of light.
The light rays incident on a PV cell produces disturbance in its atomic structure which results in the freeing of the electrons into conduction, thereby constituting an electron flow.
The above flow of electrons produces a potential difference across the cell terminals, since the current involved is DC, the developed potential difference has a positive and negative polarization across the terminals.
However, the voltage from a PV cell may be too less and insignificant, and therefore cannot be used for driving any form of load.
Therefore many individual PV cells are connected in series to form a solar panel such that it becomes practically useful for driving electrical loads.
The total number of PV cells inside a solar panel determines how much voltage the panel would generate, while the total area of the cells determines the magnitude of current.
Using an ordinary digital multimeter to check a solar panel specifications
Understanding Solar Panel Voltage and Current Specs
Just like any other power supply equipment, a solar panel may be also specified with two basic parameters: voltage and current.
Voltage is the pressure at which the electrons are pushed across output and current is the amount of electrons that's been released.
There's another parameter that's essentially involved with solar panels that is the wattage.
Wattage is nothing but the product of the above explained voltage and current ratings.
The voltage of a solar panel is specified by measuring its ability to produce voltage across its terminals at peak incident sunlight over its surface, without any load connected across its terminals.
The current rating is specified by measuring its ability to generate current at peak incident sunlight with its output terminal short circuited.
The above ratings can also be verified at home by the user by conducting the above procedures, and measuring the results using a digital multimeter (please see the image above)
Simple connection details of a standard solar charger/controller/regulator device
How to Use a Solar Panel
In the above sections we learned a few important basic things involved with solar panels. We understood the fact that actually solar panels are quite easy to understand and does not involve much technical complexities.
In this section we will try to understand how to use a solar panel at home, which is again pretty simple to implement.
Since the output of a solar panel is heavily dependent on the amount of sunlight, it's never consistent and would vary with the position of the sun.
Therefore for acquiring a constant DC output from a solar panel generally a controller device becomes imperative in conjunction with it.
Normally the dealer would himself suggest you the correct controller/regulator equipment for the procured soar panel.
The connections involved are not too difficult. It's all about integrating the solar panel output with the input of the controller. Once this is set up, a constant DC at the required level could be accessed from the output of the controller/regulator device.
This output can be directly used for driving electrical gadgets such as music players LED lights, DVD players, laptops, or for charging cell phone batteries etc.
Since the above output would be a DC, and at a low voltage level, it wouldn't be suitable for driving AC appliances.
In order to make the above supply useful for AC appliances, an inverter equipment may be incorporated.
During day time, the solar output through the regulator may be used for charging the specified inverter battery, and at night the above stored battery power may be utilized for operating the inverter and the connected AC appliances such as fluorescent lights, fans ACs, heaters, TV set, refrigerator etc.