<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Drake,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>-20 to -28F is my best estimate. I do not have minimum registering temperature gauges at inverter locations. The coldest areas in Vermont get down to 40 below every few years. I don’t have inverters in the coldest locations. I’ve seen -15F out my front door a few times already this year. If I walk 300 feet away from the house and take a reading in a field 40 feet in elevation below the house, the temperature is 6 to 8 degrees lower there.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dave<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Drake<br><b>Sent:</b> Thursday, January 19, 2012 9:14 AM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] Electrolytic Caps vs. Thin Film Caps<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal>Dave,<o:p></o:p></p></blockquote><p class=MsoNormal><br>That is really good news. I went through this with Steve Jefferson and SMA recently. They said that -13F was the limit. Steve has posted to this effect on the list, but I couldn't find it in the archives. The recommendation was that I get a Canadian model, but was not able to. Where we are, it seldom gets below zero, but has historically gotten to -26 officially, and according to many it has gotten below - 30. The customer has agreed to shut down the outdoor unit if it gets below -10F. It would be good to know that SMA's recommendations are over cautious. What is the coldest you have seen your inverters operate at?<br><br>Thanks,<br><br>Drake <br><br><br><br><o:p></o:p></p><p class=MsoNormal>Drake,<br> <br>Before installing Sunny Boys outside I did some checking several years ago. I spoke with some installers in cold locations in the USA and also spoke with contacts at SMA. The word back then was although the manual states -13F, they felt the SB’s would be OK outdoors here in Vermont. I also go the go ahead from Solectria and Fronius. James Worden, top boss at Solectria said -40F. The Fronius engineer told me that the electronics in their inverters were basically the same components that they use in their welders, and that the welders sit outside in Siberia, in the winter. <br> <br>We try and install inverters in the basement, or garage, whenever possible but have many outdoors with no problems so far. <br> <br>All Earth Renewables have been installing hundreds of trackers here in Vermont and they all have Sunny Boys mounted on the pole.<br> <br>Best,<br>Dave<br> <br> <br><b>From:</b> re-wrenches-bounces@lists.re-wrenches.org [<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org"> mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Drake<br><b>Sent:</b> Wednesday, January 18, 2012 6:47 PM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] Electrolytic Caps vs. Thin Film Caps<br> <br>The SMA inverters will suffer capacitor damage if operated below -10F, from what I've been told. Do you have different information? <br><br>At 09:19 AM 1/15/2012, you wrote:<br><br>Hello David,<br><br>The minimum temperature rating for grid-tied inverters<br>is dependent on the manufacturer's specifications. It's<br>a choice they make as a part of the product design<br>and certification.<br><br>The manufacturer must specify the coldest temperature<br>as a part of their UL1741 certification effort, and<br>that's the coldest to which it will be tested and<br>verified as operational by the UL certification<br>laboratory (NRTL). Will it operate below the min<br>temperature spec? It might. But then again, it's<br>not verified to do so. Some bad things can happen<br>if the components don't handle cold very well, and<br>power is applied (such as actual failure of parts.)<br><br>Quality electrolytic capacitors are generally rated<br>to -40C (which also happens to be -40F). Film caps<br>are often rated for temperatures below -40C, but at<br>-40C, other components such as microprocessor clock<br>crystals and many integrated circuits will fail to<br>operate, so the point of film caps being rated for<br>colder temperatures than electrolytic caps is moot.<br><br>Note this is "fail to operate", not "fail".<br><br>Cold-temperature components rated to -55C *could* be<br>used in inverter construction, but parts of this type<br>add cost (sometimes considerably) to the finished<br>product price.<br><br><br>By the way .. to your point of cold temperature specs<br>not appearing in writing ...<br><br>Our PVAC Modules *are* rated to operate at -40C, and<br>have been tested to that temperature by the UL test<br>lab. This rating is stated in writing in our brochures<br>as well as the PVAC Module Installation Manual/User's<br>Guide.<br><br><br>Dan<br><br><br><br>--- On Sun, 1/15/12, Dave Palumbo <dave@independentpowerllc.com> wrote:<br><br>> From: Dave Palumbo <dave@independentpowerllc.com><br>> Subject: Re: [RE-wrenches] Electrolytic Caps vs. Thin Film Caps<br>> To: "'RE-wrenches'" <re-wrenches@lists.re-wrenches.org><br>> Date: Sunday, January 15, 2012, 7:32 AM<br>> Dan,<br>> <br>> Any worries with inverters located out in 30 below zero<br>> temps with either Electrolytic Caps or Film Capacitors?<br>> It's very cold here this AM (minus twenty something F)<br>> and it makes me wonder about all the inverters, both<br>> micro's and string, outside in cold weather areas. We've<br>> been told in the past by SMA, Fronius and Solectria that<br>> we should be good down to 40 below, although this is<br>> typically not found in their technical documents in<br>> print.<br>> <br>> David Palumbo<br>> Independent Power LLC <br>> 462 Solar Way Drive<br>> Hyde Park, VT 05655<br>> <a href="http://www.independentpowerllc.com/">www.independentpowerllc.com</a> <br>> NABCEP Certified PV Installer<br>> Vermont Solar Partner<br>> 24 Years Experience, (802) 888-7194 <br><br>_______________________________________________<br><br>_______________________________________________<br>List sponsored by Home Power magazine<br><br>List Address: RE-wrenches@lists.re-wrenches.org<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: <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><o:p></o:p></p><p><span style='font-size:10.0pt'>Drake Chamberlin <br>ATHENS ELECTRIC LLC<br>OH License 44810 <br>CO license 3773<br>NABCEP Certified PV</span><o:p></o:p></p></div></body></html>