I've done patch jobs on little 12 v systems, and had them hold up for
many years, but I concur, I wouldn't try that at higher PV voltages.
Silicon sealant actually is slightly conductive, at least according to
other Wrenches when this subject came up several years back.
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 9/1/2014 2:43 PM, Martin Herzfeld wrote:
I concur with Dan. Unless a controlled environment, a patch job on a
module with a customer is wrong on so many levels.
Martin Herzfeld
California Solar Contractor License #833782
Trenching Contractor, Pole Installation & Maintenance, Instrumentation
UL Certified PV Installer #17, OSHA 30
Principal Contract Solar Technical Inspector
OSHA-Authorized Construction Trainer
CompTIA Certified Technical Classroom Trainer (CTT+) #T3NSZCNBBKB4QTQG
Project Contractor & Consultant
Telephone & Text: 510-243-0190 <tel:510-243-0190>
Ron,
It's been my experience the only adhesives that work reliably on PV
backsheets are those designed for the purpose, such as Dow 804 et.
al.. Substances such as silicone sealant, tool polymerics, and others
will appear to be suitable when first applied, but they eventually
peel loose over a period of 1-5 years.
Issue #2: Heat of sufficient temperature to melt the backsheet may
also have been hot enough to affect solder joints on and among the
cells. Crystallized solder connections will conduct current, but are
more resistive, and eventually will degrade due to heating and
cooling, leading to overheating and eventual failure. Then too
there's a possibility of micro-fractures created in the cells due to
the heat, which take time to become apparent, but will also cause a PV
module to quit working .. or at least quit working at its rated
specifications.
Issue #3: When PV are manufactured, the layers at a minimum are
manufactured from tempered glass, EVA, cells and buss, EVA, then the
backsheet (tedlar, kevlar, etc.), in that order. The module is
assembled under conditions of heat and vacuum. With the backsheet
melted, the environmental integrity of the laminate has been
compromised, allowing ambient humidity into the PV. While it may be
functional now, long-term prospects for continued proper operation are
questionable at best.
Unless there's a pressing reason to try to salvage the module, it's
better to replace it.
Dan Lepinski
--------------------------------------------
On Sun, 8/31/14, Ron Young <solarea...@solareagle.com
<mailto:solarea...@solareagle.com>> wrote:
Subject: [RE-wrenches] PV panel backing
To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org
<mailto:re-wrenches@lists.re-wrenches.org>>
Date: Sunday, August 31, 2014, 6:32 AM
Hello Wrenches,
I have an installation of 165w PV on a pole mount that was exposed to
a fire from the rear when the customers shop burned. 6 of the 10
panels survived with only replacement of the MC4 plugs required but
one of the panels that is still functioning had the rear coating
melted off. The cells and electrical grid still function. Can anyone
recommend a replacement coating that may salvage this panel for a few
more years. I know if left exposed it will soon deteriorate but am
wondering if some kind of commonly available non conductive rubberized
or latex type of coating might do the job?
Ron Young
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