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  • 1.  Panel discoloration

    ASES Life Member
    Posted 12-16-2021 01:13 PM
    Hi - I installed an AC array in Fall, 2019 consisting of 14, Talesun 275W modules, each with an Enphase M215 microinverter.  One of the panels is starting to turn a brownish color (see photo - the bottom 2 rows are the Talesun modules, all of them are not shown).  So far, it still performs identically to its neighbors, but I'm wondering if the panel is on its way toward failure.  Anyone seen this before?  Thanks.

    Mike Curran
    Retired from (dare I say it?) Fossil Plant Mgt.

  • 2.  RE: Panel discoloration

    Chapter Leader
    Posted 12-17-2021 08:23 AM
    Mike -
        We have been using some 'older', discolored (from concentrated sunlight), PV modules in addition to others not 'discolored' ... (not the 24V as Talesun), and they are still working, although, there is a slight lowered output and I imagine 'not to worry' ... unless there is a drastic drop !
        We received the discolored modules and checked the voltage and amperage output, before adding to our 'meager' PV array here in Maine !

    Peace -
    John Burke
    Maine Solar Energy Association;  SEADS of Truth, Inc.
    Downeast Alternative Design Solar, Inc.  (DADS, Inc.)
           -  (207) 546-1639;  (516) 669-2442
    "Sometimes doing your best is not good enough. Sometimes you must do what is required."
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  • 3.  RE: Panel discoloration

    ASES Life Member
    Posted 12-17-2021 09:33 AM
    Thanks John.  That's reassuring, except I bought these panels brand new 2 years ago.  FYI, they are Talesun #TP660P-275, with Voc=38.7V.  ​

    Mike Curran
    Retired from (dare I say it?) Fossil Plant Mgt.

  • 4.  RE: Panel discoloration

    ASES Life Member
    Posted 12-19-2021 04:37 PM
    Hi Mike,

    This kind of discoloration was common in PV modules until the industry learned to UV stabilize encapsulants back in the early 1990s.

    Looks like this particular module may have missed out on the UV inhibitor application. It's the EVA encapsulant that is degrading (browning), not the actual cells. It will still work for many years, but as it darkens the power output will gradually drop due to lower transmissivity and it will fall out of spec.

    You may be able to make a warranty claim to have that defective module replaced by the manufacturer. Worth a try. You should replace with a module with same nameplate current and voltage outputs.

    Good luck

    Robert Foster
    Assistant Professor
    New Mexico State University, College of Engineering
    Las Cruces NM