Hi Allen, Thanks for the assessment. I think that makes a lot of sense. I prefer to be conservative with my grid-tied numbers, too. Maybe I'll just round down the Suneye projections.
Dana Dana Brandt Ecotech Energy Systems, LLC www.ecotechenergy.com [email protected] 360.318.7646 On Tue, Oct 28, 2014 at 3:38 PM, Allan Sindelar <[email protected]> wrote: > Dana, > I'm not going to answer your question directly, but rather I'd like to add > to Ray's comments. In short. use the SunEye for grid tie work; use the > Pathfinder for off grid. If you don't do off grid (most installers don't > any more, if they ever did) don't bother with the Pathfinder. Off grid > seldom if ever deals with multiple roof angles, as modules aren't typically > mounted on roofs. > > Details: > 1. Grid tie is competitive, so you want the most accurate estimate of > production. I believe the SunEye is more accurate, or at least more > "liberal" in its output. > 2. Your competitors will most likely use the SunEye, so you'll need to > offer its level of apparent professionalism, as well as match their output > projections. > 3. For off grid, I want the inherent conservatism of the Pathfinder; for > grid-tie, not so much. I have almost zero history of customers' off grid > systems being undersized, in large part because of the inherent > conservatism of the Pathfinder, combined with our 37º latitude, as Ray > mentioned (meaning we're at the outer edge of the 6º latitude template > spread), and also combined with our high-elevation, dry-air insolation > often exceeding the standard 1,000 w/m2. Together this meant that my > systems typically and routinely exceeded their projected output. Nobody has > ever complained about that. > 4. Grid tie customers never go on the roof with the designer/salesperson > to look at a sunpath chart. They just want the results - a PV system that > looks good and saves them money. Off gridders are usually way more involved > in the design and customer education process. The Pathfinder sunpath chart > is so simple to read that doing charts while picking an array site is a > shared part of the educational part of the design/sales process. So it > leads to the treasured "ah-hah!" moment when the client really gets what's > going on, and gets fully engaged in the design of "their" system in the > process. > > They're two different tools serving completely different purposes. I > prefer the analog nature of the Pathfinder, but not for the usual and > predictable reasons. > > Allan Sindelar > www.sindelarsolar.com > > *Allan Sindelar* > [email protected] > NABCEP Certified PV Installation Professional > NABCEP Certified Technical Sales Professional > New Mexico EE98J Journeyman Electrician > Founder (Retired), Positive Energy, Inc. > *505 780-2738 <505%20780-2738> cell* > > > On 10/28/2014 3:32 PM, Ray Walters wrote: > > I've not done a side by side comparison, but the Pathfinder seems to be > slightly conservative, especially depending on which latitude sheet you are > using. I sometimes switch sheets and try both, when the latitude is close > to falling between (ie 37 deg, and there is 37 to 43 sheet or a 31 to 37 > sheet) Checking against actual sun locations at the solstices, it seems > to be close, but I think they would rather err on the side of caution. > I've used the Path finders for decades, and find them ideal for discussing > shading issues on site with the customer, as every one can look at it at > the same time. > For more complicated shading analysis, I can see the Suneye being more > useful. Depending on the situation, I could see using both, but the > Pathfinder is better for off grid, as we don't have accurate insolation > values at these remote locations, so detailed analysis has limited value > anyway. We're primarily looking at which trees need to be trimmed. > > R.Ray Walters > CTO, Solarray, Inc > Nabcep Certified PV Installer, > Licensed Master Electrician > Solar Design Engineer303 505-8760 > > On 10/28/2014 3:19 PM, Dana Brandt wrote: > > Hi Wrenches, > > We've been using the Pathfinder along with the Pathfinder Assistant > software for several years and mostly like it. My concern with it is > there's no way to combine two or three shading images to account for a > string of modules spanning those different shading conditions. I've spoken > with the Pathfinder folks and they don't seem to understand or acknowledge > that limitation. How have you dealt with this? > > So I bought a Suneye. Their software can apparently calculate string > shading including multiple solar access readings. > > I took both the Pathfinder and the Suneye out on my next site assessment > and have run the results of side by side measurements. The Suneye is > showing about 10-15% better solar access for each measurement that the > Pathfinder Assistant software. I'm concerned to see such different numbers. > Has anyone else done a side by side comparison? What have you seen? > > Thanks, > > Dana > > Dana Brandt > Ecotech Energy Systems, LLC > www.ecotechenergy.com > [email protected] > 360.318.7646 > > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & > settings:http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette:www.re-wrenches.org/etiquette.htm > > Check out or update participant bios:www.members.re-wrenches.org > > > > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & > settings:http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette:www.re-wrenches.org/etiquette.htm > > Check out or update participant bios:www.members.re-wrenches.org > > > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/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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