<font size="2"><font face="arial,helvetica,sans-serif">First, I'd suggest swapping the inverter under the suspect module with it's neighboring module's inverter. See if the reduced output follows the module, or the inverter. If it follows the module, then I'd have a frank talk with the module manufacturer, backed with the data you've gathered, to see how they'll respond before yanking it out and shipping it back. As you note, it may be within spec, due to the tolerance of measurement error. Worst case, you've got instant vision as when the performance degrades further to the point of clear warrantable failure.</font></font><div>
<font size="2"><font face="arial,helvetica,sans-serif"><br></font></font></div><div><font size="2"><font face="arial,helvetica,sans-serif"><br clear="all"></font></font>Phil<div>-----------</div><div><span style="font-family:Arial, Helvetica, sans-serif;font-size:12px;line-height:15px">"</span><span style="font-family:Arial, Helvetica, sans-serif;font-size:12px;line-height:15px">When we learn how to store electricity, we will cease being apes ourselves; until then we are tailless orangutans. You see, we should utilize natural forces and thus get all of our power. Sunshine is a form of energy, and the winds and the tides are manifestations of energy. </span><span style="font-family:Arial, Helvetica, sans-serif;font-size:12px;line-height:15px">Do we use them? Oh, no! We burn up wood and coal, as renters burn up the front fence for fuel. We live like squatters, not as if we owned the property. </span></div>
<div><span style="font-family:Arial, Helvetica, sans-serif;font-size:12px;line-height:15px"><br></span></div><div><span style="font-family:Arial, Helvetica, sans-serif;font-size:12px;line-height:15px"></span><span style="font-family:Arial, Helvetica, sans-serif;font-size:12px;line-height:15px">There must surely come a time when heat and power will be stored in unlimited quantities in every community, all gathered by natural forces."</span></div>
<div><span style="font-family:Arial, Helvetica, sans-serif;font-size:12px;line-height:15px">-- Thomas Edison --</span></div><br>
<br><br><div class="gmail_quote">On Thu, Jun 9, 2011 at 6:32 AM, Mark Frye <span dir="ltr"><<a href="mailto:markf@berkeleysolar.com">markf@berkeleysolar.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div>
<p><font size="2" face="Arial">Folks,</font>
</p>
<p><font size="2" face="Arial">Has anyone used Enphase monitoring data to get warranty replacement on new modules with sub par yield?</font>
</p>
<p><font size="2" face="Arial">I have several interesting questions stemming from access to Enphase module level monitoring data.</font>
</p>
<p><font size="2" face="Arial">Looking at data from a larger site (80 modules) with no shading issues, instant power production indicates a high degree of uniformity in panel power (Sharp NU-U240F1 and D380) easily within 1%.</font></p>
<p><font size="2" face="Arial">So what can we now say about the precision and accuracy of this monitoring data? It seems the old school thinking for string inverters was all the monitors were 5% off and reporting 5% more power than actual.</font></p>
<p><font size="2" face="Arial">Based on the data that I am looking at, it seems the microinverter meters must be fairly precise and possibly fairly accurate as well. Uniformity of module performance must also be fairly high.</font></p>
<p><font size="2" face="Arial">In any case, this data clearly shows a single module that is not performing as well as it's cohorts. For power levels above 50% of STC, it averages 9% less power than all other modules in the system. So off to Sharp for a warranty replacement? Yes, but, what if I am 5% low on the report from my inverter meter and 5% lower on my power from this one module? What if the module gets back to Sharp and they say it is within spec, now the costs are all mine?</font></p>
<p><font size="2" face="Arial">Interestingly enough, access to this monitoring data is making more work for me as an installer. With a string inverter, I would monitor power production readings monthly and be happy so long as yields were higher than what I projected when I designed and bid the job. Pretty much fire and forget.</font></p>
<p><font size="2" face="Arial">Now I am spending time on evaluating this data and doing the work to change out the module under warranty and so forth. I am going to end up putting in quite a few hours into this for what: to recapture 10% of 1/80 of total system yield….0.0013%.</font></p>
<p><font size="2" face="Arial">I am not complaining, just musing over this interesting evolution.</font>
<br><font color="#888888"><font face="Arial"> </font>
<br><font size="2" face="Arial">Mark Frye</font>
<br><font size="2" face="Arial">Berkeley Solar Electric Systems</font>
<br><font size="2" face="Arial">303 Redbud Way</font>
<br><font size="2" face="Arial">Nevada City, CA 95959</font>
<br><font size="2" face="Arial"><a href="tel:%28530%29%20401-8024" value="+15304018024" target="_blank">(530) 401-8024</a></font>
<br><a href="http://www.berkeleysolar.com" target="_blank"><u><font color="#0000FF" size="2" face="Arial">www.berkeleysolar.com</font></u></a><font size="2" face="Arial"> </font>
</font></p>
</div>
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