The number of solar panels needed depends on your intentions. Your power bill will provide important information for your calculations. The bill indicates how much electricity you currently use, which you need to use to figure out the kWh of electricity usage your panels need to produce.
The other important measure is the insulation value. Solar panels unarmored cable require a certain level of intensity in the sunlight. Should there be low intensity, it will reduce the power they can generate. The intensity varies during the day, and during the year. Locations have insulation values and you should know the insulation value of your location. Maps of these values are accessible online. With this measurement, you can simply divide the kWh of electricity you will need to produce daily by the insulation value to determine what is needed for your panels. However, for accuracy you will you need to keep in mind there is always a loss in conversion. Generally this loss is about 25 percent. Hence, you will need to multiply whatever your final figure turns out to be by 1.25 to take this conversion loss into account. Now that you have your daily kWh requirement adjusted for insulation and efficiency, you will know how much power your solar panels should produce. To determine how many solar panels are needed, you divide the power output you calculated by the power output of a single panel. Solar maps that indicate average sun for different areas are a guide. If a solar panel is located in an area with double the score, it can produce twice the electricity with the same size panel. If you reside in a location with a low score, more or larger solar panels will be needed to produce the electricity required.
To build your own panels, knowledge about the different solar cells is a requisite. Two types of solar cells are readily available. The most efficient type is the monocrystalline cell. This is more costly, but delivers the highest energy output and lasts longer. Polycrystalline cells produce less power; but, they are also cheaper. A simple system can be devised relatively easily. After you have decided on the type of cells you want you can build such a system by gluing and mounting them on a strong backing board and wiring them. A thick piece of plywood can serve as a backing board. The armored cable sizes diagram included with the purchased cells indicates the different voltages they can produce. Decide on the voltage and thus the cells needed to produce it. Then, lay the cells in a rectangle to give you the size you need for the backing board.
After the backing board is sized correctly and cut, the solar cells can be mounted on it. They are attached using a silicone caulk. Applying caulk to the middle of the back of each cell, then lay out all the cells in the layout you decided on and glue each cell in place. The next step is to wire the cells together to form a panel. If you have bought pretabbed cells you will need to solder the tabs together. Otherwise, you will have to solder on tabs before you attach the cells. If you plan on using a charge controller you will not need a diode, which prevents the current from flowing back into the panel from the batteries, when there is no sunlight. But, if you plan to attach the cells to the battery, you may want to solder on a diode. Once this process is completed, you need to enclose the panels in a weatherproof structure.
Plexiglass or Lexan material can be used for the transparent top which allows sunlight to strike the cells. A liberal amount of caulking seals the enclosure. Your unit is complete and is ready to be placed on the roof or the ground location you have decided on. The enclosure may be built from different materials. The easiest material to use is wood and the simple system described here will not need anything different. The enclosure dimensions will depend on the number of panels you intend to use. The transparent top will have to be cut accordingly. Inside the enclosure the cells will be attached to a piece of wood or material. The wood cut to make the enclosure will need to be screwed together. Of course, a hole must be drilled for the solar panel wires to exit the box from the bottom of the enclosure. The wooden panel with attached solar cells will be glued into the container. The transparent top will need to be put down on top of the container. A connector can be soldered to the end of the wires depending on what the panel will be attached to. The panel can be tested by hooking up a voltmeter to the panel in direct sunlight. Your experiment with solar electricity can then begin and show you how to save money with solar panels you build yourself.
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