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Fellow RE-Wrenches,<br>
<br>
What offerings exist for curve tracers like Glen refers to? Comments
on specific models?<br>
<br>
Thanks,<br>
<pre class="moz-signature" cols="72">--
Bill Loesch
Solar 1 - Saint Louis Solar
314 631 1094</pre>
<br>
<br>
<div class="moz-cite-prefix">On 10/4/2015 9:52 PM, Glenn Burt wrote:<br>
</div>
<blockquote cite="mid:20151005025218.864E4102E5@che.dreamhost.com"
type="cite">
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<div>
<div style="font-family: Calibri,sans-serif; font-size: 11pt;">Why
wouldn't you invest in an I-V curve tester like the Solmetric
PVA series and let it do the heavy lifting of the testing you
are looking for?<br>
Or am I missing something in what you are looking for?<br>
<br>
Sincerely,<br>
Glenn Burt<br>
Sent from my 'smart' phone so please excuse grammar and typos.</div>
</div>
<div dir="ltr">
<hr><span style="font-family: Calibri,sans-serif; font-size:
11pt; font-weight: bold;">From: </span><span
style="font-family: Calibri,sans-serif; font-size: 11pt;"><a
moz-do-not-send="true" href="mailto:frenergy@psln.com">frenergy</a></span><br>
<span style="font-family: Calibri,sans-serif; font-size: 11pt;
font-weight: bold;">Sent: </span><span style="font-family:
Calibri,sans-serif; font-size: 11pt;">10/4/2015 21:56</span><br>
<span style="font-family: Calibri,sans-serif; font-size: 11pt;
font-weight: bold;">To: </span><span style="font-family:
Calibri,sans-serif; font-size: 11pt;"><a
moz-do-not-send="true"
href="mailto:re-wrenches@lists.re-wrenches.org">RE-wrenches</a></span><br>
<span style="font-family: Calibri,sans-serif; font-size: 11pt;
font-weight: bold;">Subject: </span><span style="font-family:
Calibri,sans-serif; font-size: 11pt;">[RE-wrenches] PV testing</span><br>
<br>
</div>
Wrenches,<br>
<br>
As time passeth, we're bumping more into older PVs/arrays
that have <br>
questionable outputs. After minimizing the variables (dust,
temps, sun <br>
angle, wiring, expected deterioration with age, etc) and still
coming up <br>
with low numbers. Testing individual PVs' Voc and Isc don't seem
to tell <br>
the whole story as they often look good.<br>
<br>
Would not a definitive test be to wire a suspect PV to an
<br>
inexpensive mppt CC (oxymoron?) and then to an orphaned battery.
The <br>
battery would have to have a mondo (surplus) rheostat paralleled
to it to <br>
maintain a steady voltage during the test. With appropriate
metering in <br>
place, you would then have Vmmp and Immp as the rheostat is
tweaked to hold <br>
a steady batt voltage and the CC finds the knee.<br>
<br>
Help me here. I know its a little spendy to cobble up but
the value <br>
of nailing an offender might be worth it. Am I missing
something? Is it <br>
common for inverters to fall off in output gradually?<br>
<br>
Bill<br>
Feather River Solar Electric </blockquote>
<br>
<pre class="moz-signature" cols="72">
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