Variation of output with mounting angle

Where can I see a chart/graph showing the relationship between solar incidence angle and current output for a solar panel.  I am interested in the BP380 but I assume that most units are similar.  I am trying to assess the need for providing a tilt mount.
Thank you. Edward.

 

Hi Edward,

http://www.yourhome.gov.au/technical/fs67.html is quite useful, particularly the graph that shows the variation of solar panel output with orientation and tilt angle. The figures are for Australian latitudes - but you can get the idea at least!

Solar panels do give pretty good output even when not angled directly towards the sun. The graph shows that, for 35 degrees latitude, the optimum angle is 35 degrees (not surprisingly) but a horizontal panel will still be around 85% efficient, and a vertical panel will still be around 65% efficient.

Note that the difference is smaller during overcast conditions, when light is scattered anyway. At those times, there is practically no difference in output between a panel mounted horizontally, and one mounted at the optimum angle.

There is a graph of optimum angles for solar panels across Europe on our information site.

regards,
Andy
Midsummer Energy