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Basics of Solar Power

What is a solar cell and how does solar power work? Here you will find a simple introduction to the technology for the uninitiated.

What is a Solar Cell?

Single solar cell A solar cell or photovoltaic cell is a device which generates electricity directly from visible light by means of the photovoltaic effect. In order to generate useful power, it is necessary to connect a number of cells together to form a solar panel, also known as a photovoltaic module. There is more about the the different types of solar cell here. The nominal output voltage of a solar panel is usually 12 Volts, and they may be used singly or wired together into an array. The number and size required is determined by the available light and the amount of energy required.

Can the power be stored?

Solar power system The amount of power generated by solar cells is determined by the amount of light falling on them, which is in turn determined by the weather and time of day. In the majority of cases some form of energy storage will be necessary.

In a Grid-connected system, the solar array is connected to the mains. Any surplus power is sold to the electricity company, and power is bought back from them when it is needed.

In a Stand-alone system, however, this is not possible. In this type of system the usual choice for energy storage is the lead-acid battery. The number and type of batteries is dependent on the amount of energy storage needed. Find out more about batteries here.

Power Control

No matter what, sometimes there will be too much power. Other times there won't be enough. In a stand-alone system the battery will be damaged if it is allowed to be overcharged or over discharged, so a controller is needed to protect it. Read more about controllers here.

The smallest systems may have only a few 12 Volt lights, but in bigger systems 230 or 110 Volts will probably be needed. An inverter is used to transform the low voltage DC generated by the solar panels into mains voltage AC. An different type of inverter is needed in a grid-connected system to convert the surplus power in order to export it to the grid.

Rationalising your energy usage is the next step to building a successful solar powered system.