Fellow RE-Wrenches,
What offerings exist for curve tracers like Glen refers to? Comments on
specific models?
Thanks,
--
Bill Loesch
Solar 1 - Saint Louis Solar
314 631 1094
On 10/4/2015 9:52 PM, Glenn Burt wrote:
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?
Or am I missing something in what you are looking for?
Sincerely,
Glenn Burt
Sent from my 'smart' phone so please excuse grammar and typos.
------------------------------------------------------------------------
From: frenergy <mailto:frene...@psln.com>
Sent: 10/4/2015 21:56
To: RE-wrenches <mailto:re-wrenches@lists.re-wrenches.org>
Subject: [RE-wrenches] PV testing
Wrenches,
As time passeth, we're bumping more into older PVs/arrays that
have
questionable outputs. After minimizing the variables (dust, temps, sun
angle, wiring, expected deterioration with age, etc) and still coming up
with low numbers. Testing individual PVs' Voc and Isc don't seem to tell
the whole story as they often look good.
Would not a definitive test be to wire a suspect PV to an
inexpensive mppt CC (oxymoron?) and then to an orphaned battery. The
battery would have to have a mondo (surplus) rheostat paralleled to it to
maintain a steady voltage during the test. With appropriate metering in
place, you would then have Vmmp and Immp as the rheostat is tweaked to
hold
a steady batt voltage and the CC finds the knee.
Help me here. I know its a little spendy to cobble up but the
value
of nailing an offender might be worth it. Am I missing something? Is it
common for inverters to fall off in output gradually?
Bill
Feather River Solar Electric
---
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