Nowadays, it is relatively easy to build your own solar panels. You can even make your own solar cells but it is easier to buy them. Solar cells have become cheap and very efficient. It does not make sense financially to build them yourself. Building your own solar panels is fun but generally it is safer to buy ready-made solar panels.
You need to be aware that building your own solar panels have some potential drawbacks as well. You are unlikely to be allowed to connect your homemade solar panels to the utility grid. In most countries, only approved power generation devices are allowed to be connected to the utility grid. Tax credits and other government subsidies of solar panels are seldom valid for DIY solar panels. While it is easy to build solar panels, it is much more difficult to build reliable solar panels which can withstand the high temperatures in which they have to operate. In worst case, your solar panels could catch fire.
Still, if you are into electronics, building your own solar panel is an interesting exercise. But it is unlikely that it will pay off financially.
The basic element in solar panel systems is the photovoltaic (PV) cell, also called solar cell. It is the PV cell that converts sunlight into electricity. It is possible to build your own solar cells but they will be clearly inferior to the ready-made cells you can buy. Fortunately, solar cells are cheap to buy. Just be aware that very cheap solar cells are often rejects, which will not perform as well as standard PV cells. In most cases, the more efficient the solar cell, the more expensive it is.
Once you have the solar cells, you need to wire them together and put them into a container. The solar cells are connected together in series and parallel to achieve useful levels of voltage and current. The efficiency of PV cells varies a lot, some cells are more efficient than others. But temperature also affects a cell’s efficiency. Typically, for every degree (centigrade) over its rated temperature range, a solar cell loses about 0.5% of its specified power.
The standard 3×6 inch solar cell generates 0.5 Volt. The most popular solar panel is made up of 36 cells connected in series, generating 18 volt and about 3 ampere. Solar cells come pre-tabbed or non-tabbed, for most people it is well worth paying extra for pre-tabbed solar cells. If you are not good at soldering, you may damage solar cell when you solder the tabs. If you are going to build 18 volt solar panels, buy packs that contain multiples of 36 cells.
Then you need to make the frames for your solar panels. This involves no high-tech work but you have to use a material that does not easily catch fire. Remember, the solar panel will spend a lot of time in the sun. Generally, a frame contains 18 or 36 cells, so you can easily connect 36 frames in series, giving you 18 volt. The front of the frame needs to covered to protect the electric wiring, sheets of acrylic are generally used for this.
Putting the individual PV cells into the frame requires a lot of patience, this is the most delicate part of the whole project. The solar cells are fragile and they can easily be damaged. Once you have the PV cells in place you put together the electric connections for the panel and test that everything is working. For the testing a voltmeter is good to have, an inexpensive model will do.
Now you are done and can enjoy your own electricity, at least if the sun is shining.