Mac Lewis was nice enough to run some Helioscope simulations for me (thank
you, Mac). The numbers were almost identical to PVWATTS in that per kW, you
get about 1% less energy yield with a 420W/IQ7A than a 385W/IQ7+ when
operating at 208Vac. Given that the IQ7A is more costly, and presumably the
Jason,
You should dig into the PVWatts help documentation. They get into pretty
good detail on how their calculations work. You might find the answer
you're looking for there.
Thanks,
Will
--
*Will White*
Curriculum Developer
e: w...@solarenergy.org
w: www.solarenergy.org
p: 802-272-3092
Hi Jason,
I think Helioscope is more suited for this analysis.
If you send me the location, tilt, orientation, array type (roof or ground)
and modules that you'd like to compare, I can quickly model this for you.
Quite easy to do.
They also have a month free trial I believe if you would like to
Then just as a follow up, I looked at the SMA-41 datasheet. This shows that
it runs at it's highest efficiency when the output power / rated power is
about 0.4 to 0.6, and the only real loss in efficiency comes when you are
running at about 0.1 and below.
On Wed, Mar 3, 2021, 8:35 PM Dave
I've never really trusted PVWatts on this. I just did a quick test using my
location in the northeast, with all the standard values and then just
changing the DC to AC ratio. It's telling me that a ratio of 1.5 is almost
exactly the same as a ratio of 1, and that around 1.3 is best. You actually
olar Wind Works
>
> NABCEP PV Installation Professional
>
> Cell 530-448-9692
>
> www.solarwindworks.com
>
> ch...@solarwindworks.com
>
>
>
> *From:* RE-wrenches *On
> Behalf Of *Jay
> *Sent:* Wednesday, March 03, 2021 12:46 PM
> *To:* RE-wrenches
>
I've used that document many times when clients question the ratio. I wish
I knew exactly how the PVWATTS ratio calculation worked. I know there's
information on how this is all done, but I don't really have the time or
inclination to study it. I'm wondering if someone knows how accurate It is.
NABCEP PV Installation Professional
Cell 530-448-9692
www.solarwindworks.com
ch...@solarwindworks.com
From: RE-wrenches On Behalf Of Jay
Sent: Wednesday, March 03, 2021 12:46 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Enphase IQ7A 3 phase limitations
Emphase has a white paper
Emphase has a white paper showing production vs module size and locations
around the country.
I don’t know if it’s more accurate than pv watts but you might check it out.
Jay
Peltz power.
> On Mar 3, 2021, at 12:13 PM, Jason Szumlanski
> wrote:
>
>
> I'm wondering how accurate the DC to
I'm wondering how accurate the DC to AC ratio is when using PVWATTS. I did
a quick PVWATTS analysis at my local area using a typical commercial roof
tilt and found that using a 420W module on an IQ7A versus a 385W module on
an IQ7+ yields almost identical results. The 420W module has 1% less
...@solarwindworks.com
From: RE-wrenches On Behalf Of
Jason Szumlanski
Sent: Tuesday, March 02, 2021 7:00 AM
To: RE-wrenches
Subject: [RE-wrenches] Enphase IQ7A 3 phase limitations
I was surprised to learn that the IQ7A is limited to 290 W continuous at 208
volts. That pretty much puts
Oops, that’s at 240V. My mistake.
rick brown
SolShine Energy Alternatives, LLC
Electrical & Solar Contracting Services
www.SolShineEnergy.com
Check, Virginia 24072
O: 540.235.3095
M: 540.808.9502
VA Class A Contractor Lic# 2705147660
VA Master Electrician Lic# 2710062762
VA Alternative Energy
I was surprised to learn that the IQ7A is limited to 290 W continuous at
208 volts. That pretty much puts Enphase out of the running for light
commercial jobs with new high-powered 72 cell panels. Any thoughts on this?
Jason
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