HI Ash, Backwoods solar sells 190 watt 72 cell modules that might give you some options.
jay Peltz power > On Jun 21, 2016, at 8:31 PM, Brian Teitelbaum <bteitelb...@aeesolar.com> > wrote: > > Hi Ash, > > Are you sure that there are 12 of the SolarWorld 175’s on a single string? > > Those were 72-cell modules, and I would think that having 12 in series in CO > would see open-circuit voltages over 600 VDC at least on some occasions. > That’s 864 cells in series, with would be about equal to having 14.4 typical > 60-cell modules in series. That sounds too high to me for CO. > > One option would be to reduce the number of 175’s to 10 (720 cells in series) > and match them with 12 of the 60-cell modules (also 720 cells in series). The > older modules are 5” cells, so their amperage would be lower, but as long as > you get the voltage as close as possible it should be fine. Of course, this > doesn’t account for degradation, so you may want to do some actual voltage > measurements on the old modules. > > One thing though – since twelve 280W modules is about 3360W, and you have a > 3kW inverter, there really isn’t enough room to add. The older Sunny Boys had > a much narrower MPPT voltage range, so I doubt that you could use strings > shorter than nine 60-cell modules. I don’t see how you would be able to add > much to the old inverter anyway. Adding a second inverter system may be your > only option, unless you can find some used 175’s. 18 or 20 of the 175’s, in > two strings, should work fine on the 3kW Sunny Boy. > > Brian Teitelbaum > AEE Solar > > > From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org > <mailto:re-wrenches-boun...@lists.re-wrenches.org>] On Behalf Of Ash Bowersock > Sent: Tuesday, June 21, 2016 12:48 PM > To: re-wrenches@lists.re-wrenches.org > <mailto:re-wrenches@lists.re-wrenches.org> > Subject: [RE-wrenches] Add-On to DGT, string inverter, w/Different Modules on > 2nd string > > Good day RE Wrench crew, > I’ve got a client whom installed a 2kW array with a 3kW SunnyBoy inverter a > number of years back. Due to the age of the system I assume it is single > MPPT. The client oversized his inverter in the hopes of using it for this > future expansion (and unfortunately his installer went along with it). The > original modules were 12 SolarWorld 175’s I believe, and we would be looking > at adding SolarWorld 280’s more than likely. To me it is clear that this is > poor design practice and not something I am willing to do. My recommendation > is a micro-inverter system that we tie in w/his existing using an AC > Combiner. But the client wants to know exactly why we don’t want to just add > a second string of 12 SolarWorld 280’s to his 6 year old SunnyBoy inverter. > Can someone please give me a technical reason why mixed modules on a string > inverter is “poor design practice”? > The more technical and dry an explanation, the better ;) > If you can’t convince them, bore them to tears with the details. > > Ash Bowersock > Senior System Designer > <http://www.rgsenergy.com/> > 833 W. South Boulder Road | Louisville, CO 80027 > tel 303.222.8387 > RGSEnergy.com <http://www.rgsenergy.com/> > Confidentiality Note: This e-mail message may contain confidential or legally > privileged information and is intended only for the use of the intended > recipient(s). Any unauthorized disclosure, dissemination, distribution, > copying or the taking of any action in reliance on the information herein is > prohibited. E-mails are not secure and cannot be guaranteed to be error free > as they can be intercepted, amended, or contain viruses. Anyone who > communicates with us by e-mail is deemed to have accepted these risks. RGS > Energy is not responsible for errors or omissions in this message and denies > any responsibility for any damage arising from the use of e-mail. Any opinion > and other statement contained in this message and any attachment are solely > those of the author and do not necessarily represent those of the company. > > > _______________________________________________ > 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
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