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Bill,<br>
Sunpower likes to sell overpriced, private labeled inverters along with
their modules. The make installers who want to use their modules, but
"Sunpower" inverters.<br>
David<br>
<br>
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<div class="Section1">
<p class="MsoNormal" style=""><span
style="font-size: 10pt; font-family: Verdana;">David Katz</span><span
style="font-family: Arial;"><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span
style="font-size: 10pt; font-family: Verdana;">Chief Technical Officer</span><span
style="font-family: Arial;"><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span
style="font-size: 10pt; font-family: Verdana;">AEE Solar</span><span
style="font-family: Arial;"><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span
style="font-size: 10pt; font-family: Verdana;">1155 <span
class="SpellE">Redway</span> Drive</span><span
style="font-family: Arial;"><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span
style="font-size: 10pt; font-family: Verdana;">P.O. Box 339</span><span
style="font-family: Arial;"><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span class="SpellE"><span
style="font-size: 10pt; font-family: Verdana;">Redway</span></span><span
style="font-size: 10pt; font-family: Verdana;">,
CA 95560</span><span style="font-family: Arial;"><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span
style="font-size: 10pt; font-family: Verdana;">Tel (707) 825-1200</span><span
style="font-family: Arial;"><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span
style="font-size: 10pt; font-family: Verdana;">Fax (707) 825-1202</span><span
style="font-family: Arial;"><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span
style="font-size: 10pt; font-family: Verdana;"><a
href="mailto:david@aeesolar.com">dkatz@aeesolar.com</a></span><span
style="font-family: Arial;"><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span
style="font-size: 10pt; font-family: Verdana;"><a
href="http://www.aeesolar.com/">www.aeesolar.com</a></span><span
style="font-family: Arial;"><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span style="font-family: Arial;"> <o:p></o:p></span></p>
<p class="MsoNormal" style=""><span
style="font-size: 8pt; font-family: Verdana;">DISCLAIMER: <br>
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<br>
<br>
Bill Loesch wrote:
<blockquote cite="mid:00e801caf0a1$3e864bf0$6501a8c0@solarf1dxi592n"
type="cite">
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<div><font color="#000000" face="Arial" size="2">Marv,</font></div>
<div> </div>
<div><font color="#000000" face="Arial" size="2">What would be a (or
more) reason(s) that the module manufacturer wouldn't want to be
on your approved list (and sell more modules)?</font></div>
<div> </div>
<div><font color="#000000" face="Arial" size="2">Thank you,</font></div>
<div> </div>
<div><font color="#000000" face="Arial" size="2">Bill Loesch<br>
Solar 1 - Saint Louis Solar<br>
</font></div>
<blockquote
style="border-left: 2px solid rgb(0, 0, 0); padding-right: 0px; padding-left: 5px; margin-left: 5px; margin-right: 0px;">
<div
style="font-family: arial; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal;">-----
Original Message ----- </div>
<div
style="background: rgb(228, 228, 228) none repeat scroll 0%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; font-family: arial; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal;"><b>From:</b>
<a moz-do-not-send="true" title="mdargatz@enphaseenergy.com"
href="mailto:mdargatz@enphaseenergy.com">Marv Dargatz</a> </div>
<div
style="font-family: arial; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal;"><b>To:</b>
<a moz-do-not-send="true" title="re-wrenches@lists.re-wrenches.org"
href="mailto:re-wrenches@lists.re-wrenches.org">RE-wrenches</a> </div>
<div
style="font-family: arial; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal;"><b>Sent:</b>
Monday, May 10, 2010 4:59 PM</div>
<div
style="font-family: arial; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal;"><b>Subject:</b>
Re: [RE-wrenches] Enphase performance</div>
<div><br>
</div>
<font face="Verdana">Marco,<br>
<br>
Sorry, I missed that question in the previous e-mail.<br>
<br>
A couple of points about the compatibility list:<br>
<br>
1. We include only modules that have passed our internal math check
for compatibility over the temperature range of the inverter.<br>
<br>
2. If the module manufacturer objects to being on the compatibility
list, we will not include them.<br>
<br>
Sunpower has objected, so they are not on the list.<br>
<br>
Zhejiang Wanxiang Solar Co. Ltd is also shown as compatible with the
M210.<br>
<br>
The list is only a guideline. Any module that falls within the voltage
spec over the expected operating temperature range of the installation,
and does not exceed the inverter DC input short circuit current rating
is certainly a valid combination, and the inverter is fully warranted.
Notice that module power rating is not a factor here.<br>
<br>
I hope this helps.<br>
<br>
<br>
</font>
<pre class="moz-signature" cols="72">See ya!
Marv
707 763-4784 x7016
</pre>
<br>
<br>
Marco Mangelsdorf wrote:
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<div class="Section1">
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">So
why is the Enphase 210 just limited “officially” to the Sanyo line?</span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125); font-family: 'Calibri','sans-serif';"><O:P></O:P></span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125); font-family: 'Calibri','sans-serif';">Thanks,<O:P></O:P></span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125); font-family: 'Calibri','sans-serif';">marco<O:P></O:P></span></p>
<p class="MsoNormal"><span
style="color: rgb(31, 73, 125); font-family: 'Verdana','sans-serif';"><O:P></O:P></span></p>
<p class="MsoNormal"><span
style="font-family: 'Verdana','sans-serif';">Dana, Marco, Wrenches,<br>
<br>
In most locations, if the interest is in maximum lifetime energy
production, it does make sense to use modules with STC power ratings
significantly higher than the inverter max power rating.<br>
<br>
This is explained in the whitepaper located at:<br>
<br>
<a
href="http://www.enphaseenergy.com/downloads/Enphase_White_Paper_Module_Rightsizing.pdf"
moz-do-not-send="true">http://www.enphaseenergy.com/downloads/Enphase_White_Paper_Module_Rightsizing.pdf</a><br>
<br>
Remember, under most real world conditions the module will not produce
STC rated power. The inverter WILL produce maximum rated power plus
some small percent to allow for the CEC max power test methods. Also,
the module will produce less power every year (under the same
conditions) and the inverter will produce its' max rated power for its'
entire lifetime.<br>
<br>
By the way, this all applies to string, central, or microinverters. Of
course, micros still retain the advantages of dealing with mismatch,
partial shading/soiling, etc.<br>
<br>
Bottom line is, the "perfect" match will depend on your particular
installation.<br>
<br>
<br>
</span><O:P></O:P></p>
<pre>See ya!<O:P></O:P></pre>
<pre><O:P> </O:P></pre>
<pre>Marv<O:P></O:P></pre>
<pre>707 763-4784 x7016<O:P></O:P></pre>
<p class="MsoNormal"><br>
<br>
Dana Brandt wrote: <O:P></O:P></p>
<p class="MsoNormal" style="margin-bottom: 12pt;">Something to
remember is that my simulation was for a specific location in
Washington. The answer might be different for your location and weather
patterns.<br>
<br>
I agree that it seems wrong to have the inverter rating 20% less than
the array nameplate. Typically, I would consider that sort of pairing a
poor design. You're right that there will certainly be some clipping -
especially with cloud-edge effects. The real question in my mind is not
whether the inverter will ever clip the output of the array, but what's
the real impact of that on energy generation on an annual basis. This
is what lead me to do the modeling simulations which indicated the
effect is negligible when taken in the context of the total annual
production. Compared to the whole year's sun, there just isn't that
much energy in high production spikes like cloud edge effects that the
inverters will clip - at least not around here. <br>
<br>
One thing to consider is that if you go with smaller modules you need
more inverters. You might compare the cost of the additional inverters
to the value of the 0.2% energy loss from clipping over the lifetime of
the system. <br>
<br>
Dana<br clear="all">
<br>
<br>
Dana Brandt<br>
Ecotech Energy Systems, LLC<br>
<a href="http://www.ecotechenergy.com" moz-do-not-send="true">www.ecotechenergy.com</a><br>
<a href="mailto:dana@ecotechenergy.com" moz-do-not-send="true">dana@ecotechenergy.com</a><br>
360.510.0433<br>
<br>
<O:P></O:P></p>
<div>
<p class="MsoNormal">On Mon, May 10, 2010 at 11:36 AM, Marco
Mangelsdorf <<a href="mailto:marco@pvthawaii.com"
moz-do-not-send="true">marco@pvthawaii.com</a>> wrote:<O:P></O:P></p>
<div>
<div>
<div
style="border-style: solid none none; border-color: -moz-use-text-color; border-width: 1pt medium medium; padding: 3pt 0in 0in;">
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);">I just don’t
understand why going over 20 percent of module nameplate to nameplate
inverter rating makes any sense.</span><O:P></O:P></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);"></span><O:P></O:P></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);">I regularly see
120-130 percent of nameplate amperage coming off of the array on our
office due to edge of cloud.</span><O:P></O:P></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);"></span><O:P></O:P></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);">So I have to
disagree with Dana in this instance. I see this a bad design
especially since lower output mods are so readily available these days.</span><O:P></O:P></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);"></span><O:P></O:P></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);">And what’s up with
the Enphase 210? Doesn’t it say on their latest compatibility list
(March 2010) that it’s only good for the Sanyo line? What’s up with
that especially since I know that one other manufacturer is signing off
on using the Enphase 210 with their 210-watt module, apparently with
Enphase’s approval?</span><O:P></O:P></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);"></span><O:P></O:P></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);">Marv—why is your
Enphase 210 only listed for use with the Sanyo line when there’s a
growing number of 210+ watt mods out there these days?</span><O:P></O:P></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);"></span><O:P></O:P></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);">Thanks,</span><O:P></O:P></p>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);">marco</span><O:P></O:P></p>
</div>
<div>
<div>
<p class="MsoNormal"><O:P></O:P></p>
<p class="MsoNormal" style="margin-bottom: 12pt;">I've been
concerned about pairing higher wattage modules (~230W) with the 190W
Enphase fearing a lot of clipping and power loss when the modules are
at full power. <br>
<br>
I did some modeling of this setup in PVSYST and found that the expected
loss from the inverter being underpowered is 0 - 0.2% annually
depending on the assumptions. The modeling was for northwestern
Washington State. A fifth of a percent seems pretty negligible to me
and is easily offset by removing module mismatch from the equation. So,
I'm convinced that matching modules in the 230W range with the 190W
Enphase inverters is a good design.<br>
<br>
I recently installed 4kW of 230s with the Enphase 190s and have seen
their output as high as 199W. <br clear="all">
<br>
Dana<br>
<br>
<br>
Dana Brandt<br>
Ecotech Energy Systems, LLC<br>
<a href="http://www.ecotechenergy.com" target="_blank"
moz-do-not-send="true">www.ecotechenergy.com</a><br>
<a href="mailto:dana@ecotechenergy.com" target="_blank"
moz-do-not-send="true">dana@ecotechenergy.com</a><br>
360.510.0433<O:P></O:P></p>
</div>
</div>
<div>
<div>
<div>
<p class="MsoNormal">On Fri, May 7, 2010 at 4:48 PM, Chris
Worcester <<a href="mailto:chris@solarwindworks.com" target="_blank"
moz-do-not-send="true">chris@solarwindworks.com</a>> wrote:<O:P></O:P></p>
</div>
</div>
<div>
<div>
<div>
<div>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);">Do the Enphase
inverters clip the output power to their rating like other
manufacturer’s? So a M190 can only put out 190 watts max? I have had
this question for a bit now on system performances using Enphase in
designs during our cold spring and fall days.</span><O:P></O:P></p>
<div>
<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);"></span><O:P></O:P></p>
<div>
<p class="MsoNormal"><span style="font-size: 10pt; color: navy;">Sincerely,<br>
<br>
Chris Worcester</span><O:P></O:P></p>
<p class="MsoNormal"><span style="font-size: 10pt; color: navy;">Solar
Wind Works<br>
NABCEP Certified PV Installer<br>
Phone: 530-582-4503<br>
Fax: 530-582-4603<br>
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"Proven Energy Solutions"</span><O:P></O:P></p>
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<p class="MsoNormal"><span
style="font-size: 11pt; color: rgb(31, 73, 125);"></span><O:P></O:P></p>
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<p class="MsoNormal"><b><span style="font-size: 10pt;">From:</span></b><span
style="font-size: 10pt;"> <a
href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank"
moz-do-not-send="true">re-wrenches-bounces@lists.re-wrenches.org</a>
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target="_blank" moz-do-not-send="true">re-wrenches-bounces@lists.re-wrenches.org</a>]
<b>On Behalf Of </b>Mark Westbrock<br>
<b>Sent:</b> Friday, May 07, 2010 10:33 AM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] Enphase performance</span><O:P></O:P></p>
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<p class="MsoNormal"><O:P></O:P></p>
<div>
<div>
<p class="MsoNormal">The over-reporting of energy that Randy
refers to below was much higher than any discrepancy based on
monitoring resolution. We have a pyranometer at the site, and Enphase
reported energy production as high as 38% higher that predicted from
irradiance data, as well as 38% higher than the string inverter portion
of the same system. Individual microinverters showed instantaneous
power output as high as 285 W from a nominal 190 W unit.<br>
<br>
Enphase explained that there was a software glitch that was resulting
in "double counting". It took them over two months to correct this
issue, time which is lost from our experimental comparison of string
vs. microinverter. They indicated that this seemed to be an isolated
situation, but I wonder how many Enphase customers are reporting
miraculous performance from their system without verifying via another
meter.<br>
<br>
Screen shot of a day's power production of 22 M190 microinverters
(nominal 4180 watts AC):<O:P></O:P></p>
</div>
</div>
<p class="MsoNormal"><b>Error! Filename not specified.</b><br>
<br>
Mark <O:P></O:P></p>
<div>
<div>
<pre>Mark Westbrock<O:P></O:P></pre>
<pre>NABCEP Certified Solar PV Installer<O:P></O:P></pre>
<pre>NM ER-1J Journeyman Electrician<O:P></O:P></pre>
<pre>Positive Energy, Inc.<O:P></O:P></pre>
<pre>office: 575-524-2030<O:P></O:P></pre>
<pre>cell: 575-640-2432<O:P></O:P></pre>
<pre><a href="mailto:westbrock@positiveenergysolar.com"
target="_blank" moz-do-not-send="true">westbrock@positiveenergysolar.com</a><O:P></O:P></pre>
<pre><a href="http://www.positiveenergysolar.com" target="_blank"
moz-do-not-send="true">www.positiveenergysolar.com</a><O:P></O:P></pre>
<p class="MsoNormal"><O:P></O:P></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">We
definitely experienced an overstatement. </span><O:P></O:P></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"></span><O:P></O:P></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">We
have a client who installed 5kW on a string inverter and 5kW on enphase
and it is that side-by-side comparison that enabled us to positively
identify a problem. There was a significant overstatement of output. We
finally got a Enphase person who told us it was a software glitch. The
problem appears to be fixed. They explained to us that our problem was
isolated without giving us a detailed explanation of what happened.
Since that problem was fixed, we have seen no difference in output
between a string inverter and enphase.</span><O:P></O:P></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"></span><O:P></O:P></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">Randy<br>
<br>
</span>Kirpal Khalsa wrote: <O:P></O:P></p>
<p class="MsoNormal" style="margin-bottom: 12pt;">This same issue
has come up over the years for us......first with PV Powered inverters
and then noticed in Fronius as well......We have noticed in most of our
grid tied systems that are connected thru a "revenue grade meter" for
Oregon Energy Trust production reporting, that the inverter always has
a higher performance than indicated on the "utility grade meter". We
have seen the discrepency as high as 10%. Over time this adds up to
significant kWh differences. In our experience the inverter always has
the higher kWh reporting, we have attributed this to the inverter
wanting to report a good production number, to boost their efficiency
claims......maybe even more than is accurate.....I have asked PV
Powered and Fronius about this and their line is that to put a "revenue
grade meter" into the inverter would be cost
prohibitive......interesting as the readily available revenue grade
meters are only $30-$60. I would gladly pay that much extra if I
didn't have to wire in an additional meter. <br>
I don't think this problem is unique to the Enphase units (i haven't
installed any of these), I think all inverters should be required to
install the revenue grade meters to give accurate reporting of actual
production. Similar to how states have a "weights and scales"
accuracy certification, energy consumption and production meters should
be similarly calibratable. <br>
<br>
-- <br>
Sunny Regards,<br>
Kirpal Khalsa<br>
NABCEP Certified Solar PV Installer<br>
Renewable Energy Systems<br>
<a href="http://www.oregonsolarworks.com" target="_blank"
moz-do-not-send="true">www.oregonsolarworks.com</a><br>
541-218-0201 m<br>
541-592-3958 o<O:P></O:P></p>
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