Jay, the 71V I measured was the array VOC. Accessing the wiring for individual strings is fairly difficult as the combiners are high up in a hot attic. I didn't have a lot of time on site the day I observed this problem, so didn't gather as much information as I could have otherwise.
A re-wire for more voltage looks like the solution. With 8 modules in series, allowing for a wintertime extreme minimum temp of -30C is really going to drive the VOC up there. That looks like Classic 250 territory for a long-term solution -Luke As On May 31, 2015, at 1:23 PM, jay peltz <jay.pe...@gmail.com> wrote: HI Luke, To add here. I'm unclear if you have measured each string or the whole array at 71v. I would check each string for voc/isc. And then if they are consistent, I agree that putting 2 strings in series with a new controller might help out. You can try it with the MX-60 as you are at only 142v. If it works better then a new higher voltage CC would be required for winter higher voc. Let us know what you find out. jay Luke Christy NABCEP Certified PV Installation Professional™: Certification #031409-25 NABCEP Certified Solar Heating Installer™: Certification #ST032611-03 CoSEIA Certified PV Installer Solar Gain Services, LLC PO Box 531 Monte Vista, CO. 81144 sgsrenewab...@gmail.com 719.588.3044 www.sgsrenewables.com _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
