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<p>Has anyone noticed whether the location in the string or the
array voltage makes a difference in the failures? Is this more an
issue at higher array voltages (>600 v) and at points in the
array that the voltage would be highest? We primarily do low
voltage (<200 v) off grid systems, and have not seen any
failures. But I'm wondering if we need to go back and start
looking for issues, as I can't promise that every module connector
matched the connectors we used, especially if as has been
reported, some manus used different connectors for neg and pos.</p>
<p>To further the problems, I've personally replaced what looked to
be counterfeit connectors on cheap 12 v modules. The connecting
metal was obviously inferior: very malleable and made such a poor
connection that it created an open circuit. Luckily this was at
20 v, and no melt down occurred. Also Luckily, I didn't provide
the module. <br>
</p>
<pre class="moz-signature" cols="72">Ray Walters
Remote Solar
303 505-8760</pre>
<div class="moz-cite-prefix">On 9/4/19 4:26 PM, Jerry Shafer wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAMUFgmU7UbDmdyWXVhdsOiVcTxAfEbdGR7BXK0oMVt1eup4Qkg@mail.gmail.com">
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<div dir="auto">Just to add, l had a lab and l did testing on
connectors, we found that most of the aec issues were under low
light. This appeared to be when iradiance was low and once the
irads went up the issue was less likely, this was because the
Male-female contact was not tight enough and under lower power
it would arc instead of heating up and expanding. I used a IR
Camera but could see little change due to the plastic.
<div dir="auto">Then l used an IV curve tester and shaded
partially shaded the module after several repeat testing the
connectors got warm. I would suggest making your own connector
pull out tool to check the contact pressures. This is where
you may find your problem components. It appears that early am
testing had lower volts and the inverter pushed the current up
and causes the loose connector to fail due to the lower
volts. </div>
<div dir="auto">This testing was done both in the field 1/2 meg
and lab testing results were very close.</div>
<div dir="auto">The modules used for testing were Trina and the
field inverters were ABB and Fronius</div>
<div dir="auto">Sorry for the long note</div>
<div dir="auto">Jerry</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed, Sep 4, 2019, 2:52 PM
Steven Lawrence <<a href="mailto:lawrencesteven@gmail.com"
moz-do-not-send="true">lawrencesteven@gmail.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>Everyone,</div>
<div><br>
</div>
<div>Just to add to this, I've seen multiple melted
connectors that couldn't be traced to anything other than
mixing manufacturers. I've seen some connectors where you
can clearly seeing arcing on the pin itself and nowhere
else. The crimps and the housing were fine. I've
postulated it had to do with slightly different metals
expanding/contracting at different rates. I've made it a
very hard rule at my company to never mix manufacturers of
connectors. When we order modules, we specifically have
the PO call out the manufacturer of the connector (can't
just be "MC4 compatible"). Typically we order that same
brand of connectors, but sometimes we end up getting 6"
jumpers made by a harness company (there are some
connectors out there that can only work with #12 wire.
Can't use them on #10 homeruns). It's drastically cut
down on the number of melted connectors. We've averaged
maybe 1 or 2 on 6MW projects over a year with this hard
requirement versus 100+ we had on a 1MW rooftop project
that mixed multiple manufacturers.</div>
<div><br>
</div>
<div>Steven Lawrence<br>
</div>
</div>
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