Similar to my previous contention about module warranties, as PV module and microinverter prices plummet, it becomes less important to squeeze every watt out of a module. True, we have limited physical space to deal with, but ultimately it boils down to $/watt, or more accurately $/watt-hour.
If standardization results in significantly lower costs with some lost efficiency, does it really matter? Something to think about... Jason Szumlanski Fafco Solar From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Keith Cronin Sent: Wednesday, August 24, 2011 9:24 PM To: William Miller; RE-Wrenches Subject: Re: [RE-wrenches] Enphase 215 William It seems like the product tries to be everything to all mod manu's, which is hard to do, at best. Don't know if its a limitation in the electronics or design architecture. Could also be a strategic position to clamp down on what can be plugged into the circuit per NEC to limit their exposure to liability and keeping up with the myriad of modules hitting the market every month. As you point out, its a delicate balance- insolation vs max harvest. Sites that are free and clear of any shading are penalized, so to speak. I suspect they are aware of this design challenge and in the future, we will see matched inverters to the mod wattage output to not leave any watts on the table. Within 24 months, we could even see things go a different direction- mods labeled AC rating first and DC second. If the inverter is built into the modules already, this make the language universal, like virtually all AC wiring in a home. Keith ________________________________ From: William Miller <will...@millersolar.com> To: Keith Cronin <electrich...@yahoo.com>; RE-wrenches <re-wrenches@lists.re-wrenches.org> Sent: Wednesday, August 24, 2011 10:49 AM Subject: Re: [RE-wrenches] Enphase 215 Keith: Her's my guess: Through the MPPT algorithm. The processor indicates near maximum output, the MPPT impedance reduces to throttle back power production. This is pure speculation, but I'm stickin' with it (untold told otherwise). Throwing away power? Yes. If MPPT is not at maximum power transfer at all times then your investment in PV is not earning it's full return. However, your inverter investment is not earning it's full return during the many hours of less than optimum insolation. These are the two factors to balance in system design. William At 01:01 PM 8/24/2011, you wrote: David, et al Yes, their literature states max output power of 215. Not sure how that is controlled, except for electronically. So this could be the shunt, so to speak and must take into consideration voltage to follow some algorithm to keep things humming along at that threshold. Having said this- are we "throwing away" power then? Keith
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