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/m
2. 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
al...@sindelarsolar.com
NABCEP Certified PV
Installation Professional
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder (Retired), Positive Energy,
Inc.
505 780-2738 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 Engineer
303 505-8760
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,
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