From: RussellMc <apptechnz@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
CC: Dennis Sanner <dennis595@gmail.com>, Jeff Finger <jfinger@telus.net>,
	ApptechNZ <apptechnz@gmail.com>, RossGMail <rossmcm@gmail.com>,
	"ken@elecsyn.com" <ken@elecsyn.com>
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Date: Wed, 11 Mar 2020 06:19:47 -0700
Subject: [EE]:: Potential early Solar Panel failure mechanism (polyamide
	backsheet failure)
Thread-Topic: [EE]:: Potential early Solar Panel failure mechanism
 (polyamide	backsheet failure)
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This page describes a NIST investigation into early failures of some
industry standard Aluminum - EVA - Silicon - backsheet.

What is eing seen is that polyamide backsheets are cracking along the cell
boundaries after a few years.

This is of likely interest to PV panel users as the failure mechanism is
obvious in retrospect, points to bad material quality, & may be able to be
mitigated

What appears to be happening is that UV reakdown of the EVA encapsulant is
producing reaction products which migrate between the individual PV cells
and attak the polyamide backsheets.

Quality conscious manufacturers have long been aware of EVA degradation.
Some glass frontsheets have reaction product scavengers and 'all EVAs are
not created equal".
The fact that some (many) panels have backsheet lifetimes in excess of 30
years indicates that corners may consciously be being cut.

My comment only: Owners of panels not covered by warranties, where these
failures are starting to appear may be able to retrofit alternative
backsheets over the existing ones before secondary damage occurs.
https://www.nist.gov/news-events/news/2020/03/nist-study-uncovers-potential=
-driver-premature-solar-panel-failures

Russell
--=20
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