Solar Photo Voltaic

Solar PV is probably the easiest technology to install on most properties. Solar panels are usually fitted at roof level, but this is by no means essential, as provided the panels have a good view of the sun, then it really makes no difference where they are sited. It is important to make sure that the PV panels have the best possible exposure to the sun and this is best when they are facing due south, or as near to that as possible. East south east and west south west, will still give good results and of course, most people will have to adopt a compromise with positioning. Check your location on this excellent interactive PV Potential Output Website.

There are various types and power ratings of panels available and the best thing to do is to analyse your power requirements and invest in enough panels to achieve this, Solar Panels are rated according to the number of peak Watts they produce in full direct sunshine. It should be remembered that most panels will only ever achieve this power for a few hours a day in June and July, but having said this, very useful amounts of energy can still be obtained all year round. Single panels can be obtained in power levels from a few Watts to around 220 Watts. If more than this is required, then panels can be arranged in series or parallel to achieve the total power required.

You need to decide what you are going to do with the solar power you harvest from your panels. Most people, when they first start with renewable energy, will decide to store the electricity produced in batteries, for later use. There are various types of batteries available and you should first tally up how much power you want to store and for how long. If you just want power for some low power room lighting, then a single small battery will probably be sufficient. If, however, you need a week's supply for the whole house, then you would need a very large bank of batteries and this will be expensive. You get what you pay for with batteries and it is always best to buy a Deep Cycle type of battery, as a normal car battery is not designed for the constant charge and discharge cycling that a solar system requires.

With a battery storage system you will also need a Solar Charge Regulator. This is a device that limits the charge to a battery system to prevent overcharging and is essential to keep your batteries in top condition. Some regulators even have a monitoring and logging system which will show you exactly how much power has been harvested and what charge level the batteries are at. Try to get one that has metering for voltage and current, so that you can be kept informed of your system's performance.

If you want more than just a low voltage system, then you are going to need an inverter to step up the battery voltage to mains voltage and frequency, 230 volts AC, 50 Hz. There are two different types of inverter available. The cheapest type only produce power whose waveform is not a pure sine wave like the mains is. This will be fine for most non-critical lighting applications etc. but televisions and computers may not be happy with them. These inverters are sometimes called Quasi- Sinewave inverters.

The best type of inverter is the type that exactly replicates the mains supply. This type is called the Pure Sine Wave invertor and is a little more expensive, but can be used to provide power for any type of mains equipment. Whichever type you decide on, be sure to choose one that will handle the power you need. Often, loads with electric motors, need a very high current to start them moving, so always buy an inverter large enough to handle this inrush current.

There is another type of inverter which enables you to dispense with the battery and charge regulator, as all power produced is fed back into the mains wiring of your house and then, if it is not used by you, it is exported to the grid. This is called a Grid-Tie Inverter and is becoming a very popular choice for renewable energy enthusiasts. Effectively, you use the electricity grid as a large battery and when you are not using your own power, it is exported for others to use. You can be paid for this exported power and most electricity suppliers have a buy back micro-generation tariff. People who have large solar PV systems installed on their houses almost always have this type of system, as it is very reliable and can be a selling point for the house.

Solar panel manufacturers often use a specific type of connector. These are waterproof types, able to withstand the relatively high voltages and currents found in modern solar PV system strings. They are usually polarised so that reverse connections are unlikely. These Solar Connectors can accommodate differing cable sizes to ensure a weatherproof seal under adverse conditions. Double insulated solar cable is available and this is specifically designed to ensure safety and efficiency over quite long lengths.

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