Tuesday, 26 January 2010


We are just about ready to start thinking about setting up a PV system. The main difficulty so far has to do with us understanding just what it is that the various Chinese suppliers have on offer. Our thinking is that we need to start by costing the various kits, all before we start thinking about our specific needs.

And just in case you dont know..... Photovoltaic or PV cells are systems that convert sunlight directly into DC electricity. Solar PV, s can be used at a domestic level for lighting, and for powering low voltage appliances like radio, TV, computer, small water pumps. A small PV system will only produce a few hundred watts of electricity at most, but when linked up with a battery, and when used efficiently, they will provide enough electricity for a small cottage. Photovoltaic systems – sometimes known as PC’s – work by converting sunlight into to DC or direct current electricity. A typical PV cell structure – made up in sandwiched layers – has a back contact, two silicon layers, an anti-reflecting coating, a contact grid, and an encapsulating surface. When the rays of the sun – in the form of photons – shower the structure, the resultant steady flow of electrons produce a minute amount of electricity in the form of a direct or DC current. The amount that each cell produces is minuscule, but if you connect a whole batch of cells – in the form of say door-size panels, or tiles on a roof – and use an inverter to turn DC to AC, then you have a relatively simple and inexpensive energy source. The most common stand alone PV systems are designed to clip on to existing roofs. In action you mount the panels on the roof, plug into existing on-grid connection, and the system is ready to go. As to just how well a typical 1000 watt system will perform in the UK, the figures suggest that it will significantly reduce energy costs over the long term. Though photovoltaic cells are rarely seen in the UK – apart from on boats and caravans, and along motorways where they are used alongside mini wind turbines to provide small amounts of power for road signs and the like – they are sometimes used in a small way to power solar collector systems. In this context PV panels are used to provide the electricity that sets the various pumps and controls in motion.


  • WHY IS THERE SO LITTLE INTEREST IN PHOTOVOLTAICS ? Apart from the fact that there is a widespread suspicion of any black-box technology where you can’t actually see the wheels turning, PV’s are still relatively high cost.
  • HOW ABOUT SIZE AND WEIGHT? So far we haven't been able to pin the various manufacturers down when it comes to weight and size...certainly they are happy to give us the power potential figures of such and such a panel, but as yet they are not so keen on giving the weight and size of the actual panels
And that's about it so far......... exciting isn't it!


  1. Panels tend to weigh about 13 kg/m2, and therefore with the mounting equipment about 16 kg/m2.

    You can find .pdf from the manufacturers, or some common ones can be found at www.evoenergy.co.uk/pvpanelssold.aspx among other places.

    As for why they're not yet widely popular; they're still seen as a very expensive technology. The imminent announcements are expected to stimulate the market a lot.

  2. Thank you Aidan

    So... I need a 2KW set up... can you list my specific needs?

  3. Interesting... we have a friend in Wales... and I reckon that when it comes to off-grid energy, that he really knows what he is talking about... he says...
    My solar array consists of 2 banks of 10x40watt 12v panels, I paid £101 each for them and the steel to construct the frame cost about £50 giving a grand total of £2070. At present they are in a fixed position pointing south with an elevation from the horizontal of 53 degrees. I'm considering converting them so as to track the sun and therefore increase their efficiency, but it will have to be done using stuff I've hoarded over the years rather than spending money I haven't got.