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<P><FONT SIZE=2 FACE="Arial">Folks,</FONT>
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<P><FONT SIZE=2 FACE="Arial">Has anyone used Enphase monitoring data to get warranty replacement on new modules with sub par yield?</FONT>
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<P><FONT SIZE=2 FACE="Arial">I have several interesting questions stemming from access to Enphase module level monitoring data.</FONT>
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<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 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">(530) 401-8024</FONT>
<BR><A HREF="http://www.berkeleysolar.com"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">www.berkeleysolar.com</FONT></U></A><FONT SIZE=2 FACE="Arial"> </FONT>
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