[groar]

Originally Posted by Daox

Do you think it has to do with the heat? The angle should be better in the summer, right?

By now the sun is already rather high so it will not change a lot during next month. The day duration is already 15 hours long. The longer day, around 21st of June, lasts 16 hours.

Apparently from installations at less than 50km from me, the 2009 winter production is up to 30% less than 2008 winter production. While I have the feeling that my system seams to work correctly then it's OK. Now I knew that been toward west I was going to loose 15% over the year and around 40% over the winter. Statistically during next 10 years there will be sunnier and cloudier years...

The heat do have an effect : several times I have seen 2 consecutive sunny days (so the sun angle difference can be ignored) and the hotter day is less productive by a few %. I didn't note the temperatures so I can't evaluate the effect per °C.

In fact since November the weather is really cloudy. Only during 2 months the production has been near the forecasted production :-( Lately there has been some sunny days with some small white clouds during all day long, but in the end of the afternoon there have been big dark clouds. Because my orientation toward west, this means I'm loosing much more than the same amount of clouds during the morning.
Once the clouds were so dark that in 2 minutes the production went from over 1.5kW to 0 and we had to switch on the light at 6PM while the sun set was at 8PM.

Thanks to EcoModder.com - Googlemap ME I'm realizing how high is my latitude (43.6°) : only 10 North American is higher than me.

Denis.