Wrenches,
Here's one I haven't seen before. 1997 grid-tie battery backup system
that was one of my first, although actual installation was by another
before I was licensed. 16 BP 275, 36-cell 12V modules, the standard of
that time. Early Outback MX60 replaced C40 around 2005; array rewired to
Hello Allan,
Did you check the Voc of each string? Is it possible that there could one
or more shorted bypass diodes in the modules?
Just a thought.
Steve Bell
Morningstar tech support
On Thu, Aug 25, 2016 at 8:04 AM, Allan Sindelar
wrote:
> Wrenches,
> Here's one I haven't seen before. 1997
If it is a module issue it could be bad solder joints, shorted diodes, or a
combination of both. I just curve traced 12 12-year old KC120s - all
except 2 tested fine for Voc with a DMM (2 were totally dead). However
with the curve tracer they all exhibited more of an IV "angle" than a
curve, goin
Brian
Can you do a solmetric type test, when you performed the amp test the volts
were at near "0" so the test does not show an accurate value, you said the
modules are brown this is not good but are they checked because if so you
are done needs new modules. I would suggest doing some additional te
Hi Allan,
I would try turning off string #3 and see what happens to the vmp.
I'm guessing it'll go up to a more normal voltage.
I just had a very similar experience, also BP modules, very brown.
2 sets of 4 billion n series to a 12v system. One set was totally dragging down
the VMP, I disconn
Steve,
Yes, in the same sequence: 75.5V, 73.8V, 73.9V, 74.0V. All just about
what I'd expect.
Brian,
I have seen that with KC120s over the years - good Voc and Isc but no
MPP. That's a known failure that Kyocera (to their credit) continues to
warrant 15 years out. But I haven't seen it with t
www.SpiritSolar.net
From: Allan Sindelar [mailto:al...@sindelarsolar.com]
Sent: Friday, August 26, 2016 2:12 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Low array voltage stumper on legacy system
Steve,
Yes, in the same sequence: 75.5V, 73.8V, 73.9V, 74.0V. All just about what
I'd expect.
Bri
Mike,
Jay's suggestion to turn off string three, the low one, is good. Plus I
can guide the homeowner by phone, thus avoiding the cost of another site
visit, so that adds appeal.
I just spoke with him. While he lacks the DMM and DC amp clamp, he is
going to record V and I in and out for each
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