<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Holt and All,<div>this is one of those places where this forum can save everyone a lot of grief. When a potentially game-changing product like the Enphase comes out with an obvious Marketing BS statement like 10 years MTBF, we all need to share out experiences with the product. Got failures? How many and how long in service? What geographic area (i.e. hot as in Arizona or cooler as in Wisconsin)? Nothing like sunshine to effect product changes. ya know?</div><div>Bob-O<br><div><div>On Mar 26, 2009, at 8:01 AM, <<a href="mailto:holtek@sbcglobal.net">holtek@sbcglobal.net</a>> wrote:</div><br class="Apple-interchange-newline"><div bgcolor="#ffffff"><div>I am working on a residential project that seems perfect for the Enphase product (long array to interconnect point run). Researching the product, I came across one of their website videos (nicely done) claiming an "MTBF of 119 years" without any explanation as to what that actually means - that is - how did they arrive at that assumption/prediction. I googled "mean time between failures". Got this - h<a href="http://www.ptsdcs.com/whitepapers/57.pdf">ttp://www.ptsdcs.com/whitepapers/57.pdf</a> - a white paper that briefly explains different methods to predict or assume system and or component failures/reliability. Interesting. The conclusion of this white paper:<font face="Arial" size="1"><font face="Arial" size="1"><p align="left">MTBF is a “buzz word” commonly used in the IT industry. Numbers are thrown around without an</p><p align="left">understanding of what they truly represent. While MTBF is an indication of reliability, it does not represent</p><p align="left">the expected service life of the product.<span class="Apple-converted-space"> </span><strong><em>Ultimately an MTBF value is meaningless if failure is undefined and</em></strong></p><p><strong><em>assumptions are unrealistic or altogether missing.</em></strong><span class="Apple-converted-space"> </span>(emphasis mine).</p><p><font face="Calibri" size="3">So my question is this: Are<span class="Apple-converted-space"> </span><em>any</em><span class="Apple-converted-space"> </span>manufacturers that use MTBF as a selling point willing to disclose how these values were obtained? Not picking on Enphase....I will contact them with to ask. IMHO, with the new stuff that will be thrown at us over the coming years, we should expect real numbers from anyone using MTBF to tout their stuff.</font></p><p><font face="Calibri" size="3">Stepping off soap box.</font> </p></font></font></div><div>Holt E. Kelly<br>Holtek Fireplace & Solar Products<br>500 Jewell Dr.<br>Waco TX. 76712<br>254-751-9111<br><a href="http://www.holteksolar.com">www.holteksolar.com</a><br></div></div></div><br></div></body></html>