Sailboat Solar Panel Sizing

[noelex 77]

Increasing temperature will reduce solar panel output, but usually increased insolation in the summer periods will more than make up for this. The average output is generally highest in summer. There are exceptions in tropical areas, but this is more due to cloud build up in summer, rather than a temperature increase.

If you are looking for the highest instantaneous output this is not usually in summer. Cooler temperatures where the sun peaks out from a cloud in the "shoulder season" will generally produce the highest peak output (sometimes exceeding the STC output), but it is short lived and has little practical impact on the total output, which is more important to most cruisers.

[s/v Jedi]

Originally Posted by noelex 77

Increasing temperature will reduce solar panel output, but usually increased insolation in the summer periods will more than make up for this. The average output is generally highest in summer. There are exceptions in tropical areas.

If you are looking for the highest instantaneous output this is not usually in summer. Cooler temperatures where the sun peaks out from a cloud in the "shoulder season" will generally produce the highest peak output (sometimes exceeding the STC output), but it is short lived and has little practical impact on the total output, which is more important to most cruisers.

Thank you Noelex: this is the first old fashioned correct post I read today. Summer, more output; winter, surprisingly good because of cooler climate which is positive for panel efficiency and decreased fridge and freezer consumption. So, even though winter solar production is lower, effect aboard is minimal because consumption is also lower. I have never seen figures of higher avg production for the winter but guess there will always be exceptions.

[sailorchic34]

Originally Posted by s/v Jedi

Thank you Noelex: this is the first old fashioned correct post I read today. Summer, more output; winter, surprisingly good because of cooler climate which is positive for panel efficiency and decreased fridge and freezer consumption. So, even though winter solar production is lower, effect aboard is minimal because consumption is also lower. I have never seen figures of higher avg production for the winter but guess there will always be exceptions.

Oh agree completely with Noelex as he said basically the same thing I said. But I'm thinking we can all agree that panel output in volts is higher in lower temps and somewhat lower with higher temps. On the order of ~1V per 20 degrees f rise above 68 degrees F. So a cool summer day panel output will be higher then on a hot summer day. Its just science after all...