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<DIV><FONT size=2 face=Arial>Hello Drake,</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>I have observed hundreds of PV systems in the early
morning and can say without doubt that string inverters are not inherently
slow to wake up.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>For example, today my 12 year old SW4048
with a single crystal PV array facing south at 12 and 18 degrees tilt and
my SB2100 with a single crystal PV array facing south at 18 degrees
both were putting out power at 7:45 am when the sun was 9 degrees
above the horizon at azimuth 105 degrees. Today the sky is clear and the sun
rose in Los Angeles at 6:57 am.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>I have seen systems with 100 kW Xantrex inverters
and flat Unisolar arrays wake up before the morning sun rose above the
horizon. Granted the systems were putting out less than 5 kW, but the
inverters were on.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>See you all at the solar conference.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Best regards,</FONT></DIV>
<DIV><FONT size=2 face=Arial>Joel Davidson</FONT></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=drake.chamberlin@redwoodalliance.org
href="mailto:drake.chamberlin@redwoodalliance.org">Drake</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=re-wrenches@lists.re-wrenches.org
href="mailto:re-wrenches@lists.re-wrenches.org">RE-wrenches</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, October 11, 2010 6:39
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [RE-wrenches] Enphase v.
string inverter</DIV>
<DIV><BR></DIV>I'm now monitoring a 5.376 kW system we recently installed. The
sun is barely up, with light clouds, and a portion of the array is still in
shade. The system is putting out 700 watts. A string inverter
would probably be waiting to start. <BR><BR>My main problem with the Enphase
is the 199 watt limit to its output. The inverters are rated for up to
235 watt modules. This 224 watt module array spends a fair amount of
time at full inverter capacity during cool sunny days. Maybe these
inverters should not be used with over 210 watt modules. <BR><BR>Drake
<BR><BR><BR><BR>At 12:50 AM 10/11/2010, you wrote:<BR>
<BLOCKQUOTE class=cite cite="" type="cite"> The main
advantage of Enphase is the module level monitoring. However, the
increased output due to partial shading can be significant. I was at a
6 year old PV site this week, and a tree had grown up near the base of the
roof. Branches were casting a few minor shadows on the array, but was
wiping out 75% of the production. I can assure you, those 9 modules
would have been producing '50+% greater output'<BR>Nick Soleil<BR>Project
Manager<BR>Advanced Alternative Energy Solutions, LLC<BR>PO Box
657<BR>Petaluma, CA 94953<BR>Cell: 707-321-2937<BR>Office:
707-789-9537<BR>Fax: 707-769-9037<BR><BR><BR><BR><FONT size=2
face=Tahoma><B>From:</B> Jamie Johnson
<jjohnson@spefl.com><BR><B>To:</B> RE-wrenches
<re-wrenches@lists.re-wrenches.org><BR><B>Sent:</B> Sun, October 10,
2010 5:38:55 AM<BR><B>Subject:</B> Re: [RE-wrenches] Enphase v. string
inverter<BR></FONT><BR>Marco,<BR><BR>The last I heard the NREL was testing
enphase vs. a string inverter, they were also suppose to test enphase vs. A
competitors module level mpp tracking. Not sure if that performance
test is complete yet. <BR><BR>I have seen 1 independent unshaded test
( potentially biased ) which IIRC showed enphase ~1% less than a string
inverter, this seems to match the inverters CEC rating.<BR><BR>What we see
around here is an over estimate of kWh production by the selling contractor
using enphase, sometimes by 50+% greater than unshaded kWh
estimates.<BR><BR>Performance guarantees with monetary compensation back to
the customer if estimates are not met can be a good thing and improve the
industry IMHO.<BR><BR>Jamie Johnson<BR>General Manager<BR>SOLAR POWER
ELECTRIC TM<BR>NABCEP Certified Solar PV Installer #031310-118<BR>(941) 380
- 0098<BR><A href="http://www.SPEFL.com">www.SPEFL.com</A><BR>Commercial
& Residential<BR>FL State Certified # EC13001765<BR><BR>Sent from my
iPhone<BR><BR>On Oct 9, 2010, at 7:07 PM, "Marco Mangelsdorf" <<A
href="mailto:marco@pvthawaii.com">marco@pvthawaii.com</A>> wrote:<BR><BR>
<BLOCKQUOTE class=cite cite="" type="cite">Does anyone know of any reports
out there from a neutral, 3<SUP>rd</SUP> party which compares an Enphase
array with an array using a string inverter with both arrays on the same
unshaded surface?<BR><BR> <BR><BR>Some Enphase peddlers here are
saying that the energy harvest from an Enphase system is going to be
better since they supposedly come on sooner and stay on later in the
day.<BR><BR> <BR><BR>One guy is actually saying that the Enphase
inverters come on before the sun comes over the horizon. Maybe
from the same family that claimed that a-Si modules produced power from
the
moonlight.<BR><BR> <BR><BR>Thanks,<BR><BR>marco<BR><BR> <BR>_______________________________________________<BR>List
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