Make your own solar panel
Posted by Solar energy guru | Filed under Solar panels & photovoltaic cells
Solar energy is often associated with high technology, so it’s surprising how easy it is to build your own solar panel. The solar cells used in commercial panels can be bought separately, and the frame can be made from common building materials. Solar panels are still expensive enough to make building one worthwhile, and it provides an interesting project for learning more about them.
When buying silicon solar cells, it is often cheaper to get second-hand or damaged cells. Some manufacturers even sell bags of broken cells which work fine as long as the thin surface wires are intact. While these cells are very cheap, they required more time to be spent on testing and soldering them together. The number of cells required depends on the desired output voltage and current of the panel. Silicon solar cells produced about half a volt regardless of their size, but their current output increases as their size increases. All the cells in a panel should be the same size so that the current is not limited by the smallest cell.
Silicon solar cells are fragile and should be enclosed in a rigid frame that will prevent bending and protect them from damage. The frame can be made of wood or metal, and the front can be made of glass or acrylic. The commercial names for acrylic include Plexiglas, Perspex, and Lucite. The usual layout is a rectangular frame with several rows and columns of cells placed close together. The frame edge only needs to be high enough to cover the cells. Unlike solar heaters, there is no need to paint the frame black or insulate it, as solar cells do not use thermal solar energy.
Before attaching the solar cells, each one should be tested with a voltmeter to check that it generates a voltage when placed in sunlight. This is especially important for broken cells which may have their thin wires separated from the surface. The cells are then placed close together with their thin wires facing outwards, and their tabs wired together. Large panels can produce over ten amperes of current, so heavy duty hookup wire should be used. Automotive wire is ideal for wiring solar panels. Once the cells are connected and arranged, they are attached to the frame by an adhesive. The cells should not be drilled or attached with screws as this will fracture the silicon.
Before adding the transparent cover, test the panel outputs with a voltmeter to check that it produces the expected voltage. Solar cells are often connected in series to boost the panel voltage. This means the positive lead from one cell is connected to the negative lead of the next cell, creating a chain of cells that start and end at the panel output leads. This is why it is important to test each cell, as one break will stop the current completely. Once the cells are fixed in place and working, the front cover can be screwed down. A bead of silicone sealant applied around the frame edge will help seal the inside from water, and sealant should also be applied to the holes where the output leads exit the frame.
Building your own solar panel can take considerable time, effort and money. But solar panels will remain expensive for some time so it is a good way to save money, and gain a source of free electricity that will last many years. They do not require any more maintenance than a commercial solar panel, and they can be quickly repaired if a wire break occurs. By using recycled materials to make the frame, the cost can be further reduced, and even the solar cells can be recycled from older panels or factory offcuts.