Solar Panels and Extremely cold weather?

ligwyd
ligwyd Registered Users Posts: 210 ✭✭
in General Solar Power Topics #1
Most panels I've seen state coldest operating temp. down to -40 degrees Celsius.(also -40F as F and C are equal at -40)
What happens when it gets colder than that? I may be doing some solar work North of where I live and it can get down to -55 C (-67 F) and thats without the windchill!
Do the panels just stop producing power or does the Voltage just continue to rise?

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    I would guess the major issue is delamination and differential expansion and contraction between the various materials (aluminum frame, glass, silicon, various plastics and bonding materials, insulation).

    Aluminum could contract and crack the glass, cold plastics and insulation can turn very brittle in extreme cold, etc.

    For the cells themselves, the Voltage does does rise when cold and output current falls (current falls at something like 1/5th to 1/10th the rate at which voltage rises, so overall power output rises as cell temperature falls).

    Found a NASA paper from 1969 looking at solar cells for use around Jupiter... 140K or -133C (-207F). From this document, it appears that the efficiency (increased voltage, less current) does continue even at -133C (for various types of Silicon Cells--There were others tested too):

    https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19700002904.pdf

    -Bill "my guess" B.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    edited November 2019 #3
    Wind chill only applies to moist skin that is evaporating water.  So it won't affect your panels. 

    What does effect panels at night is thermal radiation.   Under a clear night sky, the panel surface can easily chill 20 degrees or more, below ambient temps.  And then you would see the thermal expansion / contraction issues, trying to tear the parts of the panel apart, and when cold, the plastic does not stretch much !
    That's also the reason panels can produce high voltages right at dawn, they are super cooled from the night sky, and then the sunlight hits them - boom, the Voc is sky high (pardon the pun).  Then as the panel warms up, the Voc drops back to a much more reasonable value.
    https://theculturetrip.com/middle-east/articles/this-ancient-technique-to-make-ice-in-the-desert-is-mind-boggling/


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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #4
    I don't know about Jupiter, but we regularly get colder than Mars.  Panels work fine, but as noted stuff gets brittle in the extreme cold.  That calls for care doing things like clearing snow on/around panels.

    Hopefully the solar work is inside.  Any little breeze at those temps makes working outside uncomfortable and potentially dangerous.  
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
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