<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:p="urn:schemas-microsoft-com:office:powerpoint" xmlns:a="urn:schemas-microsoft-com:office:access" xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" xmlns:s="uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882" xmlns:rs="urn:schemas-microsoft-com:rowset" xmlns:z="#RowsetSchema" xmlns:b="urn:schemas-microsoft-com:office:publisher" xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet" xmlns:c="urn:schemas-microsoft-com:office:component:spreadsheet" xmlns:odc="urn:schemas-microsoft-com:office:odc" xmlns:oa="urn:schemas-microsoft-com:office:activation" xmlns:html="http://www.w3.org/TR/REC-html40" xmlns:q="http://schemas.xmlsoap.org/soap/envelope/" xmlns:rtc="http://microsoft.com/officenet/conferencing" xmlns:D="DAV:" xmlns:Repl="http://schemas.microsoft.com/repl/" xmlns:mt="http://schemas.microsoft.com/sharepoint/soap/meetings/" xmlns:x2="http://schemas.microsoft.com/office/excel/2003/xml" xmlns:ppda="http://www.passport.com/NameSpace.xsd" xmlns:ois="http://schemas.microsoft.com/sharepoint/soap/ois/" xmlns:dir="http://schemas.microsoft.com/sharepoint/soap/directory/" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:dsp="http://schemas.microsoft.com/sharepoint/dsp" xmlns:udc="http://schemas.microsoft.com/data/udc" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:sub="http://schemas.microsoft.com/sharepoint/soap/2002/1/alerts/" xmlns:ec="http://www.w3.org/2001/04/xmlenc#" xmlns:sp="http://schemas.microsoft.com/sharepoint/" xmlns:sps="http://schemas.microsoft.com/sharepoint/soap/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:udcs="http://schemas.microsoft.com/data/udc/soap" xmlns:udcxf="http://schemas.microsoft.com/data/udc/xmlfile" xmlns:udcp2p="http://schemas.microsoft.com/data/udc/parttopart" xmlns:wf="http://schemas.microsoft.com/sharepoint/soap/workflow/" xmlns:dsss="http://schemas.microsoft.com/office/2006/digsig-setup" xmlns:dssi="http://schemas.microsoft.com/office/2006/digsig" xmlns:mdssi="http://schemas.openxmlformats.org/package/2006/digital-signature" xmlns:mver="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns:mrels="http://schemas.openxmlformats.org/package/2006/relationships" xmlns:spwp="http://microsoft.com/sharepoint/webpartpages" xmlns:ex12t="http://schemas.microsoft.com/exchange/services/2006/types" xmlns:ex12m="http://schemas.microsoft.com/exchange/services/2006/messages" xmlns:pptsl="http://schemas.microsoft.com/sharepoint/soap/SlideLibrary/" xmlns:spsl="http://microsoft.com/webservices/SharePointPortalServer/PublishedLinksService" xmlns:Z="urn:schemas-microsoft-com:" xmlns:st="" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Mark,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Enphase actually has a pretty good explanation of voltage drop calculations in their downloads- it’s under application notes and details the drop through their cable so you can determine what voltage each of the micro-inverters will see. From that you can calculate additional losses and see how close you are getting to the high limit. You also need to know your starting point- the foothills in CA have a lot of areas where nominal line voltage is right up at the max allowable to start with, leaving very little headroom.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Gary Handelin, P.E.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Solar Independence<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";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"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Nick Soleil<br><b>Sent:</b> Tuesday, February 15, 2011 10:01 AM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] Can I handle the voltage drop?<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Hi Mark:<br> I wouldn't feel comfortable with that scenario, either. Many inverters do shut off at 254V-255V, but most of them can be adjusted if you have the software and laptop for the job. Enphase generally shuts off when the AC voltage reaches 258V-259V. Keep in mind that just the Enphase cabling can add an additional 1.75% to the rise. I break my Enphase circuits into two sub-circuits of half length.<br> Enphase is defintitely more tolerant of voltage issues than other inverters. Xantrex is the worst, but can be adjusted.<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'> <o:p></o:p></span></p></div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>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<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p><div><div class=MsoNormal align=center style='text-align:center'><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><hr size=1 width="100%" align=center></span></div><p class=MsoNormal style='margin-bottom:12.0pt'><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Mark Frye <markf@berkeleysolar.com><br><b>To:</b> RE-wrenches <re-wrenches@lists.re-wrenches.org><br><b>Sent:</b> Mon, February 14, 2011 7:42:11 PM<br><b>Subject:</b> [RE-wrenches] Can I handle the voltage drop?</span><o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Folks,</span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>I am working on a proposal. It's a ground mount 300+ feet from the meter. There is an existing, near by run of #2 copper I can tap into. The desired system is relatively large, 64 amps AC max. I have modeled the yield using PV watts hourly data, applying a power loss based on the voltage drop at the varying current. This model shows a 3% loss in annual yield with the #2 copper. Because of the economics of the system, we can absorb this loss.</span><o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>My concern however is that I do not want the inverters to shut down when operating at higher currents. I do not want a high AC line voltage fault due to the voltage drop on the line. At the 64 amps max, the drop would be about 4%. Of course all the manufactures I talk with recommend keeping the drop on the AC below 1.5%.</span><o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>I am looking at using Enphase inverters which spec an AC voltage range up to 264V, or 10% above 240V nominal.</span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>What experience have folks had out there? How far can one realistically push the 1.5% limit and still avoid AC voltage faults when there is high voltage drop on the line?</span><o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>My guess is that everything would work out fine, but I stand to loss a huge amount of energy if the inverters are spending all their time faulting and resetting during daily peaks.</span><o:p></o:p></p><p><span style='font-family:"Arial","sans-serif"'> </span> <br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Mark Frye</span> <br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Berkeley Solar Electric Systems</span> <br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>303 Redbud Way</span> <br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Nevada City, CA 95959</span> <br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>(530) 401-8024</span> <br><a href="http://www.berkeleysolar.com" target="_blank"><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>www.berkeleysolar.com</span></a><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> </span> <o:p></o:p></p></div></div></div><p class=MsoNormal><o:p> </o:p></p></div></body></html>