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Nathan,<br>
<p><a href="https://www.nrel.gov/docs/fy12osti/51664.pdf">In the
NREL report Photovoltaic Degradation Rates — An Analytical
Review by Dirk C. Jordan and Sarah R. Kurtz</a> the conclusion
is that the 0.5% or so annual degradation of PV module output is
mostly due to changes in PV module current. Other studies have
come to the same conclusion. So, long term changes in voltage
might not be worth worrying about. <br>
</p>
Kent Osterberg<br>
Blue Mountain Solar
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 4/10/2025 4:31 PM, Nathan J. Stumpff
via RE-wrenches wrote:<br>
</div>
<blockquote type="cite" cite="mid:CAA=iwJFXgfeFVFQ=GV2bXxDNzzdkfqUEdo4NEwCFWFVM0PjqAw@mail.gmail.com">
Hi wrenches,
<div dir="auto"><br>
</div>
<div dir="auto">I used to do these kind of calcs all the time but
am wicked rusty. What assumptions do you use for future
(degraded) hot temp Vmp of a PV string to check if you will
still be able to operate inside a given MPPT range? Specifically
interested in assumed yearly degradation to Vmp, assumed actual
operating cell temp, and if it is appropriate to use STC value
as the starting point and if not what would be better (NOCT?)</div>
<div dir="auto"><br>
</div>
<div dir="auto">Thanks,</div>
<div dir="auto">-Nathan</div>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
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