Beginners guide to solar panels

Solar panel info and Frequently Asked Questions

The basics:Solar Panels or Photovoltaics (pv`s) are devices which utilise the suns rays to produce free electricity,a solar panel is usually connected directly to a large 12 volt battery to replace the energy that has been used by running lighting,waterpumps,etc though they can be directly connected to 12volt fans for ventilation and cooling,very useful in summertime! The rating of the solar panel corresponds to its electrical output,to give you some idea a 4 watt solar panel will output approx 32 watthours in 8hrs of sun,or in battery terms 250 milliamps (1/4amp) of current for each hour of bright sunshine so in 8hrs a 4 watt solar panel would emit approx 2amps to be stored in your battery,this size panel is frequently used for trickle charging large 12volt batteries over a period of time, of course a 40 watt solar panel is 10x as powerful and will put back approx 2.5amps of current for every hour of bright sunshine it gets,in normal circumstances no charge controller is required with solar panels under 10 watts although adding one certainly wont harm and could even extend the life of your battery,an inverter can be connected to the battery if 240v electrics are required,these are power rated so do ensure the power consumption of the device you wish to use doesnt exceed the rating of the inverter,this scenario can be extremely useful If you are in part of the country that suffers from winter blackouts,even a small inverter will run a few low energy table lamps for quite a few hours if you use a 110ah leisure battery, all our 12v charging solar panels are diode protected,this means that they cannot discharge the battery at night,all our monocrystalline and polycrystalline panels are waterproof,our framed glass amorphous solar panels are also waterproof,the unframed glass amorphous solar panels will require sealing around the edges for permanent use outside,the easiest way to do this is to use doubled over insulating tape. A useful site for free energy info is www.homepower.com,An American site which offers a cheap magazine download every 2 months that is filled with interesting articles on this subject,the weblink to this site is now on our new links page.

 

 FAQ

 Q:What is the difference between the different types of panel ? A:Amorphous or thin film silicon panels are made out of a single sheet of silicon usually wedged between a layer of glass and plastic,they output very well indeed in sunny conditions,usually exceeding their rating but their voltage does drop considerably under cloudy conditions,monocrystalline and polycrystalline panels are very similiar,these panels are made up of individual 0.5volt cells joined in series to give the appropriate voltage,compared to amorphous panels of similiar outputs mono and poly panels would be approx half the size and weigh a lot less,their output isnt quite as good as amorphous panels under intense sun but they do perform better in cloudy conditions making them great year round panels


Q: What size 12v charging panel should I buy ? A:This depends on how quickly you want to charge your battery and how much energy you are using, a 4 watt panel will trickle charge your battery but it will take a while as it is only putting approx 1/4 amp per hour of bright sunshine back into it so on an average summers day with 8hrs of bright sunshine it will put approx 2 amps per day of energy back into it,if your battery is a leisure battery approx 50% charged with a capacity of 110amps its going to take a while to put back 55amps at just 2 amps per day,this is fine if you only intend to use the battery once a month but more often than this and you will need to buy a bigger panel. Q:Can the panel be left connected to the battery while I am using it? A:Yes,its fine to leave the panel connected to your battery whilst you are using it,this way it gets a chance to put some energy back into it as you take it out! Q:Can the panel be left connected to the battery at night or permanently ? A:Yes the panel can be left connected to the battery permanently providing it is diode protected or is used with a charge controller to prevent nighttime discharging,its a good idea to use a charge controller with all panels above 10 watts,you should definitely use one with solar panels of 20 watts and above. Q:Do solar panels work in winter ? A:Yes they will still work in wintertime but they arent as powerful as they are in the summer months, over 3 winter months on average they will output approx 25% of the energy they can output during 3 summer months. Q:Does it have to be hot for solar panels to work ? A:No,solar panels work on light not heat,in fact they will work better on a relatively cool summers day than a blazingly hot one as they tend to slow down a bit when they overheat. Q:Whats the best position to put it in ? A:if you can put it in a southerly direction at approx 90 degrees you wont go far wrong,they can be layed flat or vertical but wont be as powerful.