Basic solar panel parts

One of the reasons that building your own solar panels has become so popular is that there are really very few components involved.  A simple solar panel consists of just a few basic parts, namely an enclosure, solar cells, a substrate and wiring.   Here’s an overview of what’s involved.

Solar panel case or enclosure

This is what most people see when they think of a solar panel.  It’s the clear glass top, the frame and the backing that the solar cells are mounted on.  The case can be large enough to need a custom built metal rack for mounting on a rooftop, or small enough to be a plastic box that can be placed almost invisibly near an outdoor floodlight.  It needs to be resistant to ultra violet (UV) rays so that it doesn’t deteriorate with constant exposure to sunlight.  And the glass (usually Plexiglas) needs to be durable enough to withstand harsh weather, including hail and wind storms that could crash tree branches and other debris into it.

Substrate

This is the piece of wood, peg board or other material that the solar cells are mounted on inside of the enclosure.  It also needs to be UV-resistant to withstand prolonged exposure to direct sunlight.

Solar cells

The photovoltaic cells are similar to the silicon chips that power most computers.  They combine the silicon, metals and other materials in a way that captures direct sunlight and converts it into electricity.  The electricity can either be immediately used by direct current devices (DC) like LED lights, or stored in DC batteries and converted into alternating current (AC) to power conventional appliances like refrigerators, TVs and other electrical equipment in homes and businesses.

Tabbed and untabbed solar cells

When building your own solar panels, you can save money by buying untabbed solar cells and soldering the tabs onto the cells yourself.  This can be a good choice if you have more time than money, but it’s a tedious job.  You can save time by buying tabbed solar cells which will cut your soldering time by one-half to two-thirds.

Solar cell wiring

Once the solar cells are mounted on the substrate, they are wired to each other in a series so that they can generate electricity.  Copper wire is added to connect the solar cells to storage batteries for using the electricity later, or to connect directly to the device that the solar panel is powering like an attic fan or a solar powered toy.

Blocking diode

The blocking diode is a small component that prevents electricity that is stored in a battery from draining backward into the solar panel.  Larger photovoltaic systems use a charge controller for the same effect.