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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Hi Marco,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I would doubt you would have clipping where you except for edge of cloud effect but here are that factors that we considered:<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D'><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D'> A low coefficient of power module such as sanyo or thin film running at lower temperatures would mean the module runs closer to its rating depending on ambient temperature<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D'><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D'>In cold, high altitude areas such as Colorado and NM where the module temp frequently is close to 25 degree C<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D'><span style='mso-list:Ignore'>3.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D'>In ground mount or windy situations where the delta T to ambient is very small (might apply to you)<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D'><span style='mso-list:Ignore'>4.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D'>Where irradiance is regularly running above 1000W/m2 and the array is mounted on a tracker or when there is snow on the ground and albedo is reflecting more sunlight.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>We have seen output clipping of any inverter that is rated less than the module STC DC watts in NM including enphase.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Thanks,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Randy<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Randy Sadewic</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Positive Energy</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Office: 505 424-1112</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Cell: 505 570-0137</span><span style='color:#1F497D'><o:p></o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Kent Osterberg<br><b>Sent:</b> Saturday, January 15, 2011 6:13 PM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] Enphase and oversizing<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Marco,<br><br>Enphase has a white paper on this topic that seems consistent with observations. The results depend on the roof and the location. But even on a 12:12 roof in Denver they compute less than 0.6% annual loss with new clean 235-watt modules. I've looked for clipping events on systems with Sharp 235-watt modules that I've installed on 4:12 roofs and haven't seen much - rarely are they even near 199 watts for a few minutes. Obviously it'll be more significant with larger modules like the SW 245, but I doubt that occasional clipping that amounts to less than 1% of the possible annual output should be characterized as wasting the customer's money. That much can be lost in selecting a different inverter.<br><br>I suspect and hope that a larger inverter is in the works. But in the mean time I see putting 245-watt modules on the 190-watt inverters as working the inverter hard. Would you hesitate to put 2400 watts of PV modules on a 2-kW inverter? <br><br>Kent Osterberg<br>Blue Mountain Solar, Inc.<br><br><br>Marco Mangelsdorf wrote: <o:p></o:p></p><p class=MsoNormal>To those of you installing Enphases.<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>Other than their 210 only working with Sanyo and SunPower modules, the vast majority of other mods only work with the Enphase 190.<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>Question: what’s the max size module that you’re comfortable using with the Enphase 190?<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>In there here parts I’m seeing competitors pairing the Enphase 190 with modules in the 230+ watt range. Some are even pairing the 190 with the SolarWorld 245. Talk about wasting the customer’s money….<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>This strikes me as a bad design that essentially has the homeowner throwing away some of his/her money on unused PV horsepower. Here in the tropics, where the edge-of-cloud effect can be seen on a regular basis, I see DC nameplate AND higher coming out on the AC side of my systems.<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>I’m wondering where others are on this question of oversizing.<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal>marco<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p></div></body></html>