We design around a 1.3 to 1.4 DC to AC ratio these days. We do see others going higher but that's generally for multi-MW ground mount systems when utility interconnection upgrade costs can make big leaps as the AC capacity gets higher. Back when an Astropower module was 4 bucks a watt, you'd never consider it, but at today's prices you can deal with a couple percent overall efficiency drop and still have better economics. I also agree that the PV Watts run is actually KWH/KWp/YR.
David David Buckner President Solar Energy Systems 917-848-0215 718-389-1545 [email protected] www.solaresystems.com 41 Box Street 2nd Floor, Brooklyn, NY 11222 The information contained in this email message, including any attached files transmitted, is confidential and may be legally privileged. It is intended for the sole use of the individual(s) named above. If you are the intended recipient, be aware that your use of any confidential or personal information may be restricted by state and federal privacy laws. If you, the reader of this message, are not the intended recipient, you are hereby notified that you should not further disseminate, distribute or forward this email message. Email transmission cannot be guaranteed to be secured or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses. The sender therefore does not accept liability for any errors or omissions in the contents of this message, which arise as a result of this e-mail transmission. If you have received this email in error, please notify the sender and immediately delete the material from your computer system. Thank you. ________________________________ From: RE-wrenches <[email protected]> on behalf of Jerry Shafer via RE-wrenches <[email protected]> Sent: Monday, January 27, 2025 8:41 PM To: RE-wrenches <[email protected]> Cc: Jerry Shafer <[email protected]> Subject: Re: [RE-wrenches] PV watts question CAUTION: External Email. Interesting topic, what l am seeing is over throttling which will potentially contribute to mid day clipping. Many inverters now can be overdriven by as much as 200% but the inverter will only produce it's rated output and 150% well that's right in there. But hey what do l know. Looking forward to other ideas Fun times On Mon, Jan 27, 2025, 11:56 AM jay via RE-wrenches <[email protected]<mailto:[email protected]>> wrote: HI All I’m working with a customer who’s pretty savvy and is using PV watts for his design. What I can’t figure out is the kwh/year goes down if he uses dc/ac ration of 1.5 instead of 1.2 which is the default. Hes in Santa Fe NM. .8 ratio= 1663 kwh/yr 1.0 ratio = 1668 kwh/yr 1.2 ratio = 1671 kwh/yr 1.5 ratio = 1623 kwh/yr I was expecting that more PV = more kWh/yr. What am i missing? standard module fixed roof mount 14.08 loss’s 10 degree tilt 180 degrees jay _______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org<http://re-wrenches.org/> List Address: [email protected]<mailto:[email protected]> Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/[email protected]/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org<http://www.members.re-wrenches.org/>
_______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: [email protected] Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/[email protected]/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
