<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Thanks for your reply August. I'm quite surprised that you have two Uni-Solar systems not performing well. Third party testing consistently proved them the top performer. (eg. Santa Cruz and Tucson sites) With my experience both on and off grid, I am convinced. </div><div><br></div><div>Panasonic was great because, in addition to performance, it also had very high efficiency. In my world of cramming 2kW+ PV arrays on the roof of an RV or boat, that is also a necessity. Example: Here's todays job; the last of my Panasonic stock, 1410 Watts on a 40' coach. No possible way to do this with standard 60 cell modules.</div><div><br></div><div><img height="182" width="320" apple-width="yes" apple-height="yes" id="9c9de87d-2b05-41d9-a1cc-bb7679e24003" src="cid:5B53377E-EED7-40EF-9DB0-CE6BA0B1E91D@Home"></div><div><br></div><div>Bottom line for me is, someone has a best and worst performing PV module just like someone has the most efficient. Glad to hear your SunPower installs are producing above expectations. That's probably what I will go with.</div><div><br></div><div>Larry</div><div><br></div><br><div><div>On Mar 14, 2014, at 9:50 AM, August Goers <<a href="mailto:august@luminalt.com">august@luminalt.com</a>> wrote:</div><br class="Apple-interchange-newline"><div>Hi Larry,<br><br>It sounds like you are talking about the temperature coefficient or energy<br>yield per kW-peak? Uni-Solar was great on paper but I'm not so sure about<br>real world performance. We have a couple of Uni-Solar systems installed a<br>while back and they are not doing so well in the real world. Companies<br>keep coming to me over the years claiming that their modules harvest more<br>kWh per kW peak and it is really hard to keep everything straight.<br>Certainly the PTC ratings help in comparison to STC. Then there are papers<br>like this from SunPower claiming 8 to 10% more energy per Watt:<br><br><a href="http://www.solarips.com/admin/content/uploads/SunPower_Yield_Report_BEW.pd">http://www.solarips.com/admin/content/uploads/SunPower_Yield_Report_BEW.pd</a><br>f<br><br>SunPower also claims that their modules degrade less annually compared to<br>others.<br><br>And here's a doc comparing PV module performance measurements:<br><br>http://fire.nist.gov/bfrlpubs/build05/PDF/b05047.pdf<br><br>Each year we try to compare the actual monitored performance of our<br>systems compared to our as-built production estimates at time of the<br>installation completion. In general, I've found that both SunPower and<br>other standard efficiency modules seem to outperform the normal PV-Watts<br>calculation by 7 to 10%. In 2012 our systems were averaging about 17%<br>above our estimates! I haven't seen a huge difference between SunPower and<br>standard efficiency modules. Furthermore, I haven't seen the performance<br>gains that microinverter manufacturers are claiming compared to string<br>inverters. I admit that our informal comparison is not perfectly<br>scientific because there are simply too many variables that we don't<br>capture. My main concern is material and or workmanship degradation in<br>modules over the long haul. Only time will tell.<br><br>Best,<br><br>August<br><br><br><br><br><br><br></div></div></body></html>