<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial,helvetica,sans-serif;font-size:12pt">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.<br><div> </div>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<div><br></div><div style="font-family: arial,helvetica,sans-serif; font-size: 12pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Mark Frye <markf@berkeleysolar.com><br><b><span style="font-weight: bold;">To:</span></b> RE-wrenches <re-wrenches@lists.re-wrenches.org><br><b><span style="font-weight: bold;">Sent:</span></b> Mon, February 14, 2011 7:42:11 PM<br><b><span style="font-weight: bold;">Subject:</span></b> [RE-wrenches] Can I handle the voltage drop?<br></font><br>
<title>Can I handle the voltage drop?</title>
<p><font face="Arial" size="2">Folks,</font>
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<p><font face="Arial" size="2">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.</font></p>
<p><font face="Arial" size="2">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%.</font></p>
<p><font face="Arial" size="2">I am looking at using Enphase inverters which spec an AC voltage range up to 264V, or 10% above 240V nominal.</font>
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<p><font face="Arial" size="2">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?</font></p>
<p><font face="Arial" size="2">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.</font></p>
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<br><font face="Arial" size="2">Mark Frye</font>
<br><font face="Arial" size="2">Berkeley Solar Electric Systems</font>
<br><font face="Arial" size="2">303 Redbud Way</font>
<br><font face="Arial" size="2">Nevada City, CA 95959</font>
<br><font face="Arial" size="2">(530) 401-8024</font>
<br><a rel="nofollow" target="_blank" href="http://www.berkeleysolar.com"><u><font color="#0000ff" face="Arial" size="2">www.berkeleysolar.com</font></u></a><font face="Arial" size="2"> </font>
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