I have a decidedly skeptical opinion of the Fronius MPP algorithm. A few years ago, I was one of the first (I believe) to notice a curious "continuous saw tooth ramping" of the DC current and voltage on a couple of Fronius IG4000's. The problem (I was told by Fronius) was triggered by an increasing Vdc crossing 240 V (the "line voltage"). The problem was fixed by a SW upgrade. Ignoring the fact that 240 Vac is not a fixed value, the standard Fronius IG inverter line may have a generic challenge when Vmp is in the 240 V range. Was this the case?
- Peter Peter T. Parrish, Ph.D., President California Solar Engineering, Inc. 820 Cynthia Ave., Los Angeles, CA 90065 CA Lic. 854779, NABCEP Cert. 031806-26 peter.parr...@calsolareng.com Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 _____ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Brooks Sent: Wednesday, July 08, 2009 4:20 PM To: 'RE-wrenches' Subject: Re: [RE-wrenches] Efficiency Curves of Fronius Inverters? Mark and Jeff, To be clear, manufacturers do not supply the data. It is required to be tested by a Nationally Recognized Testing Laboratory (NRTL). Mark's message could be misconstrued as the data being something Fronius cooked up. On another note. Anyone notice Fronius inverters having trouble finding max power? Of the 10 Fronius inverters I have looked at in the past 2 weeks, 4 were operating at a voltage well above max power and losing about 10% of the available array power. Bill. From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Mark Frye Sent: Wednesday, July 08, 2009 3:43 PM To: 'RE-wrenches' Subject: Re: [RE-wrenches] Efficiency Curves of Fronius Inverters? Jeff, Here is what they submitted to the California Energy Commision: http://www.gosolarcalifornia.ca.gov/equipment/inverter_tests/summaries/Froni us%20IG%204000.pdf Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 <http://www.berkeleysolar.com/> www.berkeleysolar.com _____ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jeff Clearwater, Village Power Design Sent: Wednesday, July 08, 2009 3:35 PM To: RE-wrenches Subject: [RE-wrenches] Efficiency Curves of Fronius Inverters? Hey Folks, Anyone have or know where I can get my hands on the efficiency vs. wattage curve for the Fronius IG series (the old series - not the Plus). I have a 4000 in stock and wondering if I can apply it to a friend's 2660 watt system without losing much to efficiency at low power levels. Best, Jeff There are numerous options here: most ground mount manu's offer ballasted systems, I would look to them 1st. Other systems I've seen or used - 1) Pour a continuous surface "footer" that is large enough in size to provide the proper ballast for the uplift in your area, pour one along the S. edge/legs and another along the back/north legs. 2) Tie all legs together via a horiz. rail at least 6' wide and embed this in a rock filled gabion, again of the required weight. 3) Limestone is easy to drill, useing a hammer drill and extension bit drill 11/16" - 3/4" holes at least 18" into the stone at an angle, vary all angles as viewed in plan as they relate to the N/S line of the array (not as they relate to level), to mitgate pull-out from them all being in a line. i.e. - 1st leg hole is 90 degrees to the N/S line, 2nd leg is 180 from this, 3rd is 45 and so on, in other words if looking in plan and you could see all holes they would radiate around the "face of a clock" with each leg hole on a different "hour". Finally, epoxy in 5/8" all thread, you can pre-bend the end to come out of the hole verticle or use a swivel connector from Uni-strut, B-line or equal. All of these suggestions should be run by a Structural Engineer before embarking, thus the 1st choice of working with a manu. Good luck! -jeff o >From the Solar, Wind and Hydro powered office of Jeff Oldham/Regenerative SOLutions ____________________________________________________________ Protect <http://thirdpartyoffers.juno.com/TGL2132/fc/BLSrjnsHGiu92lJJqoMGi0uE8kGS8cy Bf0zjvb0ir0FblIZfJXPnNi0BtXC/> your home before it is too late. Click here for homeowner insurance information. _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -- ~~~~~~~~~~~~~ Jeff Clearwater Senior Design Engineer NABCEP (tm) Certified Solar PV Installer http://www.nabcep.org/ Village Power Design/NorthEast Solar Design Turnkey Solar Design & Installation for the Commercial Sector http://www.villagepower.com goso...@villagepower.com Voice: 413-259-3776 Fax: 413-825-0703 65 Schoolhouse Rd Amherst, MA 01002 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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