<html><head><base href="x-msg://548/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Eric,<div><br></div><div>These two SolarPro magazine articles may be relevant to your troubleshooting efforts:</div><div><br></div><div><a href="http://solarprofessional.com/article/?file=SP2_6_pg34_Gleason">http://solarprofessional.com/article/?file=SP2_6_pg34_Gleason</a></div><div><br></div><div><a href="http://solarprofessional.com/article/?file=SP2_2_pg16_QandA_3&search=">http://solarprofessional.com/article/?file=SP2_2_pg16_QandA_3&search=</a></div><div><br></div><div>Best regards,</div><div><br></div><div><span class="Apple-style-span" style="font-family: Cambria; ">David Brearley, Senior Technical Editor</span></div><div><div apple-content-edited="true"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Cambria; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; ">SolarPro magazine <br>NABCEP Certified PV Installer ™<br><a href="mailto:david.brearley@solarprofessional.com">david.brearley@solarprofessional.com</a><br>Direct: 541.261.6545<br><br></span>
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<br><div><div>On Jul 21, 2012, at 3:19 PM, SunHarvest wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div bgcolor="#ffffff"><div><font size="2" face="Arial">Hello Wrenches,</font></div><div><font size="2" face="Arial"></font> </div><div><font size="2" face="Arial">I am helping a client troubleshoot a complaint about underproduction of his on-grid system installed about 6-8 years ago. At first I thought I might encounter the bad Kyocera KC120 issue but it turns out they have BP170's, 40 of them for an STC power rating of 6.8kW.</font></div><div><font size="2" face="Arial"></font> </div><div><font size="2" face="Arial">Ratings of the BP modules: PTC=150.7, Vmp=35.4, Voc=44.2, Imp=4.8, Isc=5</font></div><div><font size="2" face="Arial"></font> </div><div><font size="2" face="Arial">The system has four panels of ten modules wired in series for a nominal rating of about 350v, 4.8a per string.</font></div><div><font size="2" face="Arial"></font> </div><div><font size="2" face="Arial">At the DC disconnect (first accessible combiner) I measured: All strings right at about 375v(oc), 4.7a(mp). After the strings are combined, at the DC input of the SB6000 (with the AC power to the inverter OFF) I measured about 375V as expected. Once the AC power is connected, the SB6000 starts up, and MPP operation is initiated, the DC voltage drops to about 280V, and amps sit between 14 & 15A. I didn't think the voltage was supposed to drop upon MPP tracking...especially this much. This voltage drop would account for the observed power loss between actual and rated production values. I'm going to check with SMA but I wanted to ask the experts here too, as someone may advise something like, "Oh yeah, BP modules have a similar defect as the Kyocera..."</font></div><div><font size="2" face="Arial"></font><font size="2" face="Arial"></font> </div><div><font size="2" face="Arial">My questions:</font></div><div><font size="2" face="Arial"></font> </div><div><font size="2" face="Arial">Is the DC voltage supposed to drop significantly in MPP mode on these inverters?</font></div><div><font size="2" face="Arial">If not, does this indicate a bad inverter?</font></div><div><font size="2" face="Arial">Anyone know of problems with BP modules manufactured around 2006-2008?</font></div><div><font size="2" face="Arial"></font> </div><div><font size="2" face="Arial">The Kyocera modules showed good volts and amps until a load was connected. Seems like a similar issue here.</font></div><div><font size="2" face="Arial"></font> </div><div><font size="2" face="Arial">Eric Stikes<br>SunHarvest Solar<br>A Sustainable Energy Group Partner<br>+1 (530) 798 - 3738<br><a href="http://www.harvesthesun.com">www.harvesthesun.com</a></font></div>_______________________________________________<br>List sponsored by Home Power magazine<br><br>List Address:<span class="Apple-converted-space"> </span><a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br><br>Options & settings:<br><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a><br><br>List-Archive:<span class="Apple-converted-space"> </span><a href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><br><br>List rules & etiquette:<br><a href="http://www.re-wrenches.org/etiquette.htm">www.re-wrenches.org/etiquette.htm</a><br><br>Check out participant bios:<br><a href="http://www.members.re-wrenches.org">www.members.re-wrenches.org</a><br><br></div></span></blockquote></div><br></div></body></html>