Build Your Own Solar Panel
Why build your own solar panel?
If you live in a region or a place where you get the sun shining brightly in your backyard for a large part of the year, then you should consider having a solar panel at home.
Solar energy is free, so if you are able to tap on solar power energy, you can actually make some savings in your energy bills. This will come in especially useful with escalating energy prices, as fossil fuels become depleted and their prices soar.
And that is not all, using solar energy to power your home or office will also help you become more environmentally friendly.
When you harness more of the greener, renewable energies like solar energy, you are actually reducing your reliance on non renewable energies like oil, and helping to cut down on the carbon emissions that contribute to global warming and global climate change. Read about the advantages of solar energy.
But as many of us know, solar systems don’t come cheap. According to tlc.discovery.com, for a house that uses about 14,400 watt-hours of energy in a day, a panel measuring 26 square meters would be needed. The entire system, complete with installations like a battery bank and inverter, etc, would probably cost more than $32,000. It definitely does not make sense to spend so much just to save a couple of hundred bucks in a year.
Fortunately, there are other ways out of the situation. If you are into D.I.Y. and making your own stuff for your home, then you can consider learning how to build your own solar panel at a fraction of the original price. You will probably only need a few hundred bucks, depending on the size of the panel you construct.
Many who had a try at building homemade solar panels found the experience both enriching in terms of the learning experience and the sense of achievement with the completed project. They have also benefited from the home-made solar system that now powers their house. Read more about their experiences and tips.
So why not give it a try to build your own solar panel?
Components of a solar panel
The first step to build your own solar panel is to understand the basic components of a solar panel.
The panel comprises the tabbed solar cells secured to a backing, the panel board and its transparent plastic cover, connecting wires, batteries and a diode. Some systems may also include a charge controller and an inverter.
The solar cells are what will convert the energy from the sun into electricity. Because the electric energy produced by each solar cell is quite small, you will need many solar cells in your panel to generate the electricity you need for your house.
In turn, the panel board and its transparent plastic cover holds the fragile solar cells together, so that the energy produced by all the solar cells in the panel could be pulled together to produce the required electric current. The panel board and the plastic cover protect the solar cells from the weather elements, while the transparent cover allows sunlight to reach the solar cells.
The wires are needed to connect the solar cells in series, so that the electricity produced could flow to the batteries for storage.
The diode is needed to prevent the discharge of energy from the battery when the solar cells are not producing any electricity (e.g. when there is not enough light).
The charge controller prevents the batteries from being over charged by the solar panel system, as such, lengthening the lifespan of the batteries.
Depending on what the current produced is used for, an inverter might be needed. The output from the batteries charged by the solar panel system is direct current (DC) and can only be used for devices that work on DC (eg. 12V), such as hair dryers, vacuum cleaners. However, most household appliances such as TVs work on alternating current (AC, e.g. 110 or 220 V). Hence, the inverter is needed to convert the DC from the batteries to AC.
What you need to build your own solar panel
You’ll need the following materials to build your own solar panel
- solar cells
- plywood planks about 0.7 inches thick
- mesh (e.g. wire mesh)
- transparent plastic panel or film
- Masonite peg board
- clear silicone sealant
- nails and screws
- wood glue (optional)
- deep cycle 12 volt lead acid or gel battery (as it can be regularly recharged)
- battery box (optional, to cover the battery)
- charge controller (optional)
- inverter (optional)
You’ll need the following equipment
- a saw to work on the plywood
- screw driver
- soldering equipment
- voltage meter
- pencil or pen
The solar cells are extremely fragile. So do handle them with care. One way is to keep them within the package box, until you have built your solar panel board and are ready to install the solar cells.
For the diode, you could consider a Schottky diode as these diodes have low forward voltage drop (so less energy is wasted and there’s higher solar efficiency) and fast switching action.
Choosing the solar cells to build your own solar panel
When you build your own solar panel, solar cells are the most expensive components of the solar panel. Fortunately, you can get some reasonably priced factory-second-rate solar cells at Ebay. Or you could check out Spheralsolar.com. As factory-second-rates, it means that the cells are not in perfect shape (e.g. some may be chipped or cracked), but they are still functional and will work just fine for a home project. So unless you can and wish to spare that extra cash for extra durability and efficiency, there’s no need for perfectly new solar cells actually.
There is a wide range that you can choose from at Ebay. For example, I saw an offer for 300 monocrystalline solar cells (5x5 inches, of 0.5w to 1.8w each) for a bid of US$10.45, while another offered 400 tabbed solar cells (3x6 inches) for a bid of US$255. Look for a good deal.
Select the solar cells with metal tabs. They may cost slightly more, but solar cells that come with tabs will spare you lots of work in terms of soldering later.
In choosing the type of cells to buy, bear in mind that bigger cells produce more power but you will end up having a larger and heavy solar panel. Smaller cells give you a smaller and lighter solar panel, but you will get power. It is not a good idea to mix the small cells and the large cells within the panel, as the current and power produced by the panel is limited by the smallest cell in the panel; the higher capacity of the larger cells would be wasted. So that means you will have to find a balance and choose something that will fit both your home space and your energy needs.
If you can, buy solar cells that are NOT encased in wax. The wax encasing is intended for protection during transportation and can be extremely hard to remove from the cells. You don’t really need the wax protection; there’s not too much of a problem even if your solar cells incur some chipping. The output of your solar panel won’t be significantly affected by the chipping. Moreover, these cells you are purchasing from Ebay are after all factory second rates, meaning they would already come with blemishes, whether you have wax protection or not. So spare yourself the trouble of removing the wax prior to setting up the solar panel.
Number of solar cells to build your own solar panel
To build your own solar panel, you will need to decide on the number of solar cells to purchase, and this in turn depends on your energy needs. For a start, you might want to consider using your solar panels to supplement the grid’s supply of your home energy needs. As you become more familiar with the output of your system, you can explore replacing a larger part of the grid supply with the free solar energy.
First, calculate the amount of energy your solar system needs to produce in an hour (let’s call this figure “B”). To do so, find out the average amount of power you need (in watts) every day. The US Energy Information Agency estimates that the average energy a home uses is about 24.5 Kwh per day. Divide your daily power needs by the average number of hours of full sunlight (be conservative when calculating this) you get per day. What you then have is the average amount of power (i.e. number of watts) your solar system needs to produce in an hour for the day’s needs. Factor in energy losses from inefficiencies in the system by adding on another 30% of the original power needed.
Second, calculate the average amount of energy each of your solar cells can produce in an hour (let’s call this number “B”, by multiplying its voltage by its current flow. Use the equation: Power (in Watts) = Voltage (V) x Current (amp). Most photovoltaic (PV) solar cells produce about 0.5 volts regardless of their size. However, the current that flows through (measured in ampere) the 6×3 inches and 5×5 inches cells may range from 1 to 12 amps. Smaller cells produce more current and larger cells less. You will need to check the specifications of the cells you purchase.
Finally, divide your energy needs per hour (“A”) by the energy supply of each solar cell per hour (“B”) to determine the number of solar cells you need.
The more power you need, the less hours of full sunlight you get, the more solar cells you will need.
Do remember to buy spare cells, as solar cells are very fragile. The spares will come in useful in case any of them breaks in the course of transportation or when you are setting up the solar panel.
Preparing the panel board to build your own solar panel
The solar panel board is basically a very shallow shadow box, where you can place your interconnected solar cells (more about connecting the solar cells will be shared below) and they can be protected from the elements.
There are no strict guidelines on the configuration of this shadow box; it is very much up to your own preference. To build your own solar panel, a suggestion when deciding on the length and breath of the panel is to bear in mind the number of solar cells the panel needs to hold, how you will be arranging your cells (read section below on connecting the solar cells) and examine how much space in your garden or porch you have available for the solar panel. The panel should not be excessively large or long, otherwise moving the panel around would be difficult. For a set-up with eighteen 3”x6” solar cells, you consider consider a square 22”x22” panel board.
Then line the edges of the board with strips of the plywood to form the borders of the shadow board. Strips of 0.7” by 0.7” could be considered. You could either glue or screw the strips in place. The strip forms a protective border for the solar cells that would be placed in the panel.
When you build your own solar panel board, do remember to drill some holes (around 0.3 inches would be good) at the bottom edges of the panel board. These small holes will allow for the release of pressure built up within the panel board, when air within the board gets heated up and expands under sunlight. Be careful to position the holes so that rainwater or moisture from dew would not be able to enter the panel board readily. You can keep the insects and dust out of the panel by stuffing some mesh into the holes – in this way, only air can pass through.
Lay the inside of the panel board with a thin, firm and non conducting material, such as a Masonite peg board. This board will form the backing onto which you will be attach the solar cells.
Then give the entire board several coats of paint, to protect them from the weather elements and moisture. Also, paint both sides of the peg board to protect it from moisture – it spoils when wet. It would be even more ideal if you can find a waterproof alternative to a Masonite peg board.
Connecting the solar cells to build your own solar panel
Here’s how to connect your solar cells to build your own solar panel.
Lay out all your solar cells (back facing up) onto the peg board; you need to know exactly how all your solar cells will be positioned prior to doing any soldering. Use a pencil to make markings on the peg board to guide you. Make use of the holes in the peg board to help you.
To build your own solar panel of sufficient power, the solar cells need to be connected together in series so that you will have a higher voltage. To be connected in series, it means that tabs of opposing polarities need to be connected. In other words, the negative tab of the first solar cell needs to be connected to the positive tab of the second solar cell, and in turn, the negative tab of this second solar cell needs to be connected to the positive tab of the third solar cell, and so on. The negative tab of the last solar cell will need to be connected to the positive terminal of your battery, and the positive tab of the first solar cell will need to be connected to the negative terminal of the battery. And now you have a complete loop or circuit.
Now that you have laid out the cells and are clear how the tabs should be connected, you are ready to start soldering the solar cells together. Be gentle when soldering. If you use too much strength when handling the cells, you could break them.
After you are done with soldering the solar cells together to form a series, you can flip the entire loop around so that the back of the solar cells are now against the peg board. You might need some help at this stage.
Bring your half done solar cells grid (with the peg board as a backing) out to the sun and test it out using a voltage meter. The voltage meter should be connected to the circuit in parallel. The meter should register a voltage in the presence of sunlight. The voltage level is dependent on how many solar cells you put together in series. For example, with 18 cells (~ 0.5V each) connected in series, you should get about 9V. If you don’t get any voltage reading, you will need to check to see if your cells had been wrongly connected.
When you build your own solar panel and are sure that the cells are correctly connected, you can start gluing the solar cells onto the peg board. Apply a small patch of clear silicone sealant at the CENRTE (not anywhere else) of the underside of each solar cell. This small patch of sealant (do not use too much glue) will allow the solar cell to expand and contract according to changing temperatures without much restrictions, and so they are less likely to crack. Paste the solar cell onto the peg board, based on the pencil markings you have made previously. Remember, always handle the solar cells with lots of care. They are extremely fragile.
Putting everything together to build your own solar panel
Now, to put everything together to build your own solar panel. Place the peg board with the solar cells into the panel board that you built previously (if you haven’t already done so). Screw the peg board onto the plywood panel board to hold it in place.
Secure the diode (using the silicone sealant) within the panel board if you can. The temperatures within the panel board will be higher, allowing the diode to work more efficiently.
When you are sure that all the silicone sealant you used have cured (i.e. dried), place the transparent plastic panel that you have ready over the entire solar cells grid set-up, and screw it in place. The plastic panel will serve as a protection for the solar cells, while allowing the sun’s rays to reach the solar cells.
If you are sure that your solar panel works perfectly, you can actually seal the panel (i.e. the edges between the plywood panel board and the transparent plastic cover) with silicone sealant or aluminum tape. The seal will help keep water out of the panel. Make sure you do not block the vent holes. They are important for the release of air pressure within the panel when air within expands under sunlight.
And you’re done!
After you have build your own solar panel, place the panel in a place where it can receive the most sunlight. You may have to adjust its position as the sun moves across the sky to capture the most of the sun’s rays.
Read related articles on solar energy:
I Built My Own Solar Panel!
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