THE BASICS OF SOLAR POWER SYSTEMS   

Producing common electricity with solar power
Solar power to produce electricity is not the same as using solar to produce heat. Solar thermal principles are applied to produce hot fluids or air. Photovoltaic principles are used to produce electricity. A solar panel (PV panel) is made of the natural element, silicon, which becomes charged electrically when subjected to sunlight.  
This electrical charge is consolidated in the PV panel and directed to the output terminals to produce low voltage Direct Current - usually 6 to 24 volts. The most common output is intended for nominal 12 volts, with an effective output usually up to 17 volts. A 12-volt nominal output is the reference voltage, but the operating voltage can be 17 volts or higher much like your car alternator charges your 12-volt battery at well over 12 volts. So there's a difference between the reference voltage and the actual operating voltage.  
Solar panels are directed at solar south in the northern hemisphere and solar north in the southern hemisphere (these are slightly different than magnetic compass north-south directions) at an angle dictated by the geographic location and latitude of where they are to be installed. Typically, the angle of the solar array is set within a range of between site-latitude-plus 15 degrees and site-latitude-minus 15 degrees, depending on whether a slight winter or summer bias is desirable in the solar power system. Many solar arrays are placed at an angle equal to the site latitude with no bias for seasonal periods.  
The intensity of the Sun's radiation changes with the hour of the day, time of the year and weather conditions. To be able to make calculations in planning a solar power system, the total amount of solar radiation energy is expressed in hours of full sunlight per m², or Peak Sun Hours. This term, Peak Sun Hours, represents the average amount of sun available per day throughout the year.