Re: [RE-wrenches] Enphase and oversizing

[Kent Osterberg]

Marco, Enphase has a white paper on this topic that seems consistent with observations.  The results depend on the roof and the location.  But even on a 12:12 roof in Denver they compute less than 0.6% annual loss with new clean 235-watt modules.  I've looked for clipping events on systems with Sharp 235-watt modules that I've installed on 4:12 roofs and haven't seen much - rarely are they even near 199 watts for a few minutes.  Obviously it'll be more significant with larger modules like the SW 245, but I doubt that occasional clipping that amounts to less than 1% of the possible annual output should be characterized as wasting the customer's money.  That much can be lost in selecting a different inverter. I suspect and hope that a larger inverter is in the works.  But in the mean time I see putting 245-watt modules on the 190-watt inverters as working the inverter hard.  Would you hesitate to put 2400 watts of PV modules on a 2-kW inverter? Kent Osterberg Blue Mountain Solar, Inc. Marco Mangelsdorf wrote: To those of you installing Enphases.   Other than their 210 only working with Sanyo and SunPower modules, the vast majority of other mods only work with the Enphase 190.   Question: what’s the max size module that you’re comfortable using with the Enphase 190?   In there here parts I’m seeing competitors pairing the Enphase 190 with modules in the 230+ watt range.  Some are even pairing the 190 with the SolarWorld 245.  Talk about wasting the customer’s money….   This strikes me as a bad design that essentially has the homeowner throwing away some of his/her money on unused PV horsepower.  Here in the tropics, where the edge-of-cloud effect can be seen on a regular basis, I see DC nameplate AND higher coming out on the AC side of my systems.   I’m wondering where others are on this question of oversizing.   Thanks, marco

_______________________________________________
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