What You Need to Know About Solar Power Panels

Solar power is the latest technology to take First World countries by storm. Solar power panels come in a vast number of shapes and sizes. The smallest panel I managed to find measures a mere 35mm x 65mm and has a power output about 0.2 watts, and at the other end of the scale measuring more than five feet by three feet is a 200 watt panel. The variety of power panels in between these two sizes is enormous, and expert advice should obviously be taken in choosing the correct panel for the application in question. The maximum size of a panel is limited by its practicability and this is governed by its components and their construction. Since any number of panels may be joined together electronically either in series or in parallel, the generally accepted maximum size is about 4 feet by 5 feet. As an example, two 12 volt 2 amp panels joined in series will give 24 volts and 2 amps, whereas the same two panels joined in parallel will give 12 volts and 4 amps.

A solar power panel is made up of a number of photovoltaic cells joined together, normally in series. Individual cells on different panels may be of different power, and so we get a huge range of panels of varying powers. There are various types of solar cell, the most efficient being the monocrystaline cell. Monocrystaline is the most efficient type of cell, sometimes being as high as 20%, though 15% is more common. A thin slice or wafer is cut from a single crystal of silicon, then a very thin grid of metal is placed over the wafer and the resulting cell bonded onto a piece of plate glass. Cells are joined together by their metal grid. The joined cells are then backed by an insulating materiel, usually some form of plastic with a high thermal conductivity - this is to carry away heat produced by the cells. The panel is then finished off with edging etc. The maximum size of a panel is limited by the fact that its construction is based on a piece of plate glass and therefore quite fragile.

In smaller panels you may find the cells bonded onto a transparent plastic sheet, and some may even be somewhat flexible. Certainly some of the smaller powered panels fold up when not being used. The cost of a solar panel will generally depend upon its wattage and on the supplier. Most suppliers prices appear to be about $4.50 per watt, but this can go up to about $7.50 in more extreme cases.