In this article, I am going to talk about what each piece of a solar power system does, and what role the part plays in the system.  You don’t need every part in every solar project, but each component handles a particular job.  A typical solar power system produces electricity, stores it in batteries to be used later and then changes the DC electricity from the battery to the same kind of Alternating Current electricity that comes from the wall sockets in your home.

Solar Panels

Energy from the sun is converted into electricity by solar panels.  The panel has a layer of silicon.  When photons from sunlight strike the silicon, they knock loose electrons.  These electrons become electricity and are sent through wires.  Many solar cells, each of which generates about 1/2 volt are put together to make a single solar panel.  By putting together the correct number of solar cells, any voltage you need can be generated.  You can pretty cheaply and easily build your own solar panel and produce your own free electricity.  For a great guide to building your own solar panel, check out DIY Solar Panel

Charge Controller

The solar panels produce power and then send the power to a charge controller, which charges the batteries. The charge controller makes sure that the voltage going to the batteries is in the right range. In order to make sure that the batteries don’t overcharge it also slowly lowers the power sent to the batteries. Every once in a while after the batteries are fully charge, it will also “top off” the batteries to make sure they batteries stay fully charged. If you’re interested in more detailed information about charge controllers, take a look at Solar Charge Controller

Batteries

The majority of solar power systems use 12 volt batteries like you find in your car.  Sealed lead acid are the most common type.  These batteries are rugged, easy to find and cheap.  Weight is the only real downside, but since you aren’t going to be moving the batteries around, it isn’t really much of a problem.  Surplus batteries from places like computer UPS systems can often be found for very cheap or even free.

Power Inverter

The batteries store and put out 12v Direct Current (DC), but the appliances in your house use 120v Alternating Current (AC).  A power inverter converts the 12v DC electricity into 120v AC so you can use the electricity to power regular appliances.  There are two types of power inverter:  Modified Sine Wave (MSW) and True Sine Wave (TSW).  Of the two, TSW is the better one because it perfectly matches the electricity that comes from the sockets in your home.  A TSW inverter will cost more than an MSW inverter, but it is generally a better choice in the long run.

Complete Solar Power System

Now we will put all the parts together into a complete system.  You typically mount the solar panels on the roof.  The solar panels are connected together with wires which then deliver the electricity to the charge controller.  The power coming from the solar panels is then conditioned by the charge controller and used to charge the batteries.  The power from the charge controller is stored in the batteries all day while sunlight is hitting the solar panels.  The power inverter takes the DC electricity from the betteries and converts it to the standard 120v AC electricity that all your applicances are used to getting from the wall sockets in your house.  This type of system can be big enough to power your whole house or small enough to power just a single appliance.

If you are interested in how much it will cost for enough solar panels to power your house, check out this guide to Cost of Solar Panels