Lexan Cover For Solar Panels


The discussion of covers for solar panels comes up on the various forums from time to time.  Some locations are prone to hail.  Here in central FL, tropical storms and hurricanes are a potential threat 6 months out of every year.  Lexan (polycarbonate) is the same material used for bullet proof glass.  Even a thin piece won't break when bent.  It can be fatigued and it will eventually break, but this material is far from brittle. 

It would be possible to put spacers between the cover and the panels.  Allowing airflow, and some room for the cover to flex when taking a significant impact.

But there's a potential issue, it isn't the same optical quality of the expensive glass used for solar panels.  Is it really that big of a deal?  Watch the video.

There was a suggestion that the angle of the Lexan had something to do with the shadow.  To show that the shadow never goes away, despite the relative angle to the sun, I made the following video.


The 1/4" thick Lexan cover made about a 20% difference in the output of the panel.  This was a new piece of material, and the performance will only get worse with time as the cover ages.  Lexan is clear, it does have a slight tint to the material.  This tint creates a visible shadow, and apparently blocks enough of the light spectrum to reduce the output of the solar panels.

I don't consider these covers as a viable option.  The good news is solar panel companies perform hail impact testing.  They can take some abuse as is. 

There are some benefits in choosing a slightly smaller panel.  They are lighter, easier to carry up the ladder, no more expensive per watt than the larger panels, and if one is damaged during a storm, it's less of an impact (pun intended) to remove it from the system.  I particularly like the Kyocera 130W and 135W panels.


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Last updated 08/07/11    All rights reserved.