<div dir="ltr">I totally agree - old mods are usually not worth messing with at today's PV prices. In some cases it might be best to downsize the system and then AC couple some microinverters to cover the decrease in performance, or just replace the entire array if there are enough problems. There is a used market for smaller PV mods on Craigslist. <div>
<br></div><div>Back when I was installing Astropower 110W modules on single voltage Xantrex C40's, I never thought we'd be using anything but 12V nominal PV mods. Little did I know... Off-grid is really tough in these retrofit situations, but this applies to failed/broken mods on grid-tie systems as well. That's where I can make a good case for microinverters.<div>
<br><div id="WISESTAMP_SIG_gmail_session"><div style="font-size:13px;font-family:Verdana,Arial,Helvetica,sans-serif"><div style="margin:0 0 8px 0"><p style="margin:0"><span style="color:#808080"><strong>Jason Szumlanski</strong><em> </em></span></p>
<p style="margin:0"><span style="color:#808080"><em> Fafco Solar<br></em></span><br></p></div></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Jan 24, 2013 at 3:11 PM, Ray Walters <span dir="ltr"><<a href="mailto:ray@solarray.com" target="_blank">ray@solarray.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div>Hi Allan;<br>
<br>
I've been in the same conundrum lately. I found that AEE and
others have 12 v modules (Solartech), but the price per watt is
double or triple. My take is that somewhere around 200 to 400
watts, its more cost effective to go to the GT modules with an
MPPT controller. Blue Sky makes the 1524, and 3024 that can take
up to 57 Voc, so those would work at still fairly low cost.
Unfortunately many of the other low cost MPPT controllers won't
work with the 60 cell modules. At some point, it may actually be
cost effective to just use 60 cell modules with non MPPT
controllers, and just forget about the extra 24 cells. (I know
that sounds crazy, but PV less than $1/ watt is crazy too)<br>
<br>
I'm trying to add modules to an existing array of 8 Siemens 12 v
modules, and it just doesn't work out, except with separate
controllers. <br>
Also, its amazing how much PV you can throw at an off grid project
these days for $10k.<br>
It almost makes messing around with the old modules a waste of
time.<br>
Perhaps the solution might be to remove old arrays for customers
wanting to really up size, and then reuse the old modules for
small systems?<br>
<br>
Ray<div><div class="h5"><br>
<br>
On 1/24/2013 12:35 PM, Allan Sindelar wrote:<br>
</div></div></div>
<blockquote type="cite"><div><div class="h5">
Wrenches,<br>
We have years of installing 36-cell (12V) and 72-cell (24V)
modules for battery-based customers. Most of our systems are 24V
or 48V nominal. Over the last few years, sources of
conventionally-sized 72-cell modules have dried up - as cells have
increased in size, most modules and most newer factory production
lines have either gone to 60-cell (20V) modules, or 72 cells in
300+ watt ranges. It seems that the formerly common 72 cell, 24V
modules in the 150-190 watt range, which are well-suited to
integrating into existing systems, are no longer available.<br>
<br>
60-cell modules in the common 220-250 watt range can't be added to
an existing system unless run through a dedicated MPPT charge
controller that can convert voltage, such as an FM, XW60, Classic
or TriStar; the added cost of any of these controllers cancels out
the low prices of the modules.<br>
<br>
Who continues to manufacture 72-cell modules? Which distributors
carry them?<br>
I am aware of three options - are there more?<br>
- Sunpower makes one module in the 245 watt range that can be
used negative ground, but it's very high efficiency (and with high
Voc/Vmp as well) and very pricey;<br>
- Sanyo/Panasonic has 225-240 watt modules, but also quite
premium and pricey;<br>
- Ameresco bought the rights to manufacture many former BP
modules, and I think they make some. But we had to replace lots of
failed BP modules in that size range, and are hesitant to use
their technology, fearing that the problems may persist in the
continued line.<br>
<br>
Thank you for any discussion and recommendations.<br>
Allan<br>
<div>-- <br>
<font face="Times New Roman, Times, serif"><b>Allan Sindelar</b></font><br>
<small><a href="mailto:Allan@positiveenergysolar.com" target="_blank"><font face="Times New Roman, Times, serif" color="#000099"><u>Allan@positiveenergysolar.com</u></font></a></small><font face="Times New Roman, Times, serif"><br>
<span style="font-size:10pt">NABCEP Certified Photovoltaic
Installer<br>
NABCEP Certified Technical Sales Professional<br>
New Mexico EE98J Journeyman Electrician<br>
Founder and Chief Technology Officer<br>
<b>Positive Energy, Inc.</b><br>
3209 Richards Lane (note new address)<br>
Santa Fe, New Mexico 87507<br>
<b><a href="tel:505%20424-1112" value="+15054241112" target="_blank">505 424-1112</a></b><br>
<a href="http://www.positiveenergysolar.com/" target="_blank"><u>www.positiveenergysolar.com</u></a><u></u><u></u></span></font>
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