[RE-wrenches] 300W 72 cell micro inverters

Tue Feb 10 22:12:07 EST 2015

Regarding the clipping, which the power electronics guys would rather I=20
call "power limiting"...

To be clear, "Longer 100% production around noon" (implied in that image=20
that this is somehow beneficial) means "this system could have produced=20
more energy but didn't because the inverter was too small." Assuming=20
similar efficiencies, a 300W micro-inverter clearly would have produced=20
more energy on that day than the 250W inverter. I imagine that what you=20
mean was that if you're locked into a certain ac limit here (either you=20
can only use a 250W micro, or maybe your service conductors limit your=20
ac rating) then yes, a higher dc/ac ratio may have more power limiting=20
but will produce more energy at the expense of your kWh / kWdc yield (a=20
consideration for some projects).

Given that the ABB inverters have their highest efficiencies at the=20
higher end of their power outputs, which is not where PV modules=20
typically operate (unless you stick a 400W module on it), I'm curious=20
whether a typical 280W module would actually produce more energy over a=20
year with an Enphase 240W vs the ABB 300W in most locations. Over the=20
full Enphase power range it's more efficient than the ABB:

At ~100W dc input, Enphase is at about 96.4% efficient and the ABB 300W=20
is at 95.8%.
At ~250W input: Enphase 96.4%, ABB 96.1%.
And yes, at 315W input: Enphase 76.2% steady-state, ABB 96.4%.

It could go without saying (but I have momentum) that you should not=20
spend $2000 on a larger inverter(s) that will help your array produce=20
$200 more energy over its 25-year life. It's up to you to figure that=20
out given your site conditions and as noted in the last thread that=20
addressed this topic, weather data probably underestimates the benefit=20
due to its averaging out most short-term edge-of-cloud effects.

Anyway, maybe C250s would meet the OP's needs and they're actually the=20
slightest bit more efficient than the standard 240W unit. That is, until=20
you add the transformer since the output is 220-248V L-N. That=20
presumably makes the ABB the efficiency winner, but hopefully the above=20
is still useful. Sorry, no personal experience with any of the=20
ABB/APS/C250 units. I probably should have opened with that to save you=20
some time.

DKC

On 2015/2/10 13:05, Jarmo.Venalainen at schneider-electric.com wrote:
> Hi:
>
> One thing to keep in mind with clipping, (module over sizing), is that=20
> if a system has 10%-15% off clipping, that will not affect total=20
> annual energy harvest and depending on dust and temperature conditions=20
> will likely even improve it.
>
> Heres' a graph which shows the energy harvest graphically for a 250W=20
> module with a 250W inverter and a and 300W module with a 250W inverter.
>
>
> Please note the graph does not include any dust effects.  To=20
> compensate for dust, the modules should always be of the order of 4%=20
> more powerful than the inverter, unless you plan on washing modules=20
> every month.
>
> Related to this, large commercial systems we have been supplying=20
> inverters to are 30-70% oversized as the sinking cost of modules makes=20
> the return on investment come out as maximized in that range of=20
> oversizing,
>
> JARMO
> _________________________________________________________________________=
____________
> *
> Jarmo Venalainen*  | *Schneider Electric **|  Xantrex Brand*  |=20
> *CANADA*  | *Sales Application Engineer* *
> Phone:* +604-422-2528  | *Tech Support:* 800-670-0707  | *Mobile:*=20
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> Email:* _jarmo.venalainen at schneider-electric.com_=20
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>
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>
> From: 	Drake <drake.chamberlin at redwoodalliance.org>
> To: 	RE-wrenches <re-wrenches at lists.re-wrenches.org>,
> Date: 	02/10/2015 06:51 AM
> Subject: 	Re: [RE-wrenches] 300W 72 cell micro inverters
> Sent by: 	"RE-wrenches" <re-wrenches-bounces at lists.re-wrenches.org>
>
>
> ------------------------------------------------------------------------
>
>
>
> That  would be at the 120% rating, so by rule of
> thumb, OK. I have a ground mount that has a
> ration of 1.15% with M-190s (figuring 199 W /
> inverter). It has quite a bit of clipping in the
> spring. It has optimized tilt for the location. A
> ballasted roof mount with a 10 or 15 degree tilt
> likely wouldn't have that issue.
>
> This system went in the spring of 2010, and has
> only  had one M-190 failure out of 24, amazingly enough.
>
> At 10:22 AM 2/9/2015, you wrote:
> >What do you typically get out of a 300 watt panel for production when you
> >are grid tied? I know in theory (STC) it is a 300 watt module but we
> >rarely if ever (except in very cold weather)see near that for an=20
> output. I
> >use (as a general, 77 degrees F) design parameter, 77% for overall power
> >production output output. I'm sure you would get a little clipping, but I
> >guess a significant amount would depend on a number of variables on the
> >site, time of the year, weather conditions, etc.
> >
> >Daryl
> >
> >
> > > Yeah....if you're OK with a not insignificant amount of clipping=20
> going on.
> > >
> > > -----Original Message-----
> > > From: RE-wrenches=20
> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On
> > > Behalf Of penobscotsolar at midmaine.com
> > > Sent: Sunday, February 08, 2015 2:33 PM
> > > To: RE-wrenches
> > > Subject: Re: [RE-wrenches] 300W 72 cell micro inverters
> > >
> > > Hey Jason,
> > >    The M-250's work well with LG 300 watt (60 cell) modules.
> > >
> > > Daryl
> > >
> > >
> > >> Hi Jason,
> > >>
> > >> The Enphase C250 Microinverters for three-phase commercial
> > >> applications does work with 72 cell modules.
> > >>
> > >> On Sun, Feb 8, 2015 at 12:58 PM, Jason Szumlanski <
> > >> jason at floridasolardesigngroup.com> wrote:
> > >>
> > >>> The ABB micros seem to be solid and easy to install. We have two
> > >>> sites with them with no issues. Unfortunately, the monitoring system
> > >>> sucks compared to Enphase and was far more difficult to set up. I
> > >>> really wish Enphase would come up with a good 72 cell option because
> > >>> we find ourselves competing with 300W modules occasionally, and
> > >>> consumers (irrationally) jump to the conclusion that bigger is
> > >>> better.
> > >>>
> > >>>
> > >>> [image: Logo-Sq-80.png]
> > >>>
> > >>> Jason Szumlanski
> > >>>
> > >>> Principal Solar Designer
> > >>>
> > >>> Florida Solar Design Group
> > >>>
> > >>> (239) 491-8010 office
> > >>>
> > >>> (239) 410-4985 mobile
> > >>>
> > >>> Authorized Sales Agent for Fafco Solar
> > >>>
> > >>> [image: Fafco-Solar-Enphase-Logo.png]
> > >>>
> > >>> License CVC56701
> > >>>
> > >>>
> > >>> On Sun, Feb 8, 2015 at 3:15 PM, Bill Hennessy <bill at berkssolar.com>
> > >>> wrote:
> > >>>
> > >>>> Hi folks--
> > >>>>
> > >>>> We're planning a micro inverter install using 300W 72 cell modules
> > >>>> for an area with a fair amount of shading. The choices we've found
> > >>>> are ABB micro
> > >>>> 0.3 or APS YC500A.
> > >>>> Any stories to tell about either of these or another suggestion?
> > >>>>
> > >>>> Thanks for your time.
> > >>>>
> > >>>> Bill Hennessy
> > >>>> Berks Solar, LLC
> > >>>> 371 Centennial Rd
> > >>>> Mertztown, PA 19539
> > >>>>
> > >>>> o 610 682 4300
> > >>>> c 484 560 4666
> > >>>> NABCEP certified installer
> > >>>> PA contractor #44411
> > >>>> www.berkssolar.com
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
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> > >>
> > >> --
> > >>
> > >> Cordially,
> > >>
> > >> Nick Soleil
> > >> *Enphase Energy* | Field Applications Engineer
> > >>
> > >> office 707-763-4784 <%28707%29%20763.%204784> x7267 cell 07-321-2937
> > >>
> > >> <http://enphase.com/>
> > >>
> > >> *Powering What=C3=A2=E2=82=AC=E2=84=A2s Next*=C3=A2=E2=80=9E=C2=A2* =
| *The Enphase Energy=20
> Management
> > >> System
> > >> <http://ow.ly/HbVS3> <http://community.enphaseenergy.com/>
> > >> <http://facebook.com/EnphaseEnergy>
> > >> <http://twitter.com/Enphase>
> > >> <http://linkedin.com/company/enphase-energy>
> > >>
> > >>
> > >> NABCEP Certified Solar PV Installer #03262011-300
> > >>
> > >> California C10 Licensed Electrician #986315
> > >>
> > >> Texas Master Electrician #284451
> > >>
> > >> <nsoleil at enphaseenergy.com>
> > >>
> > >> =C3=A2=E2=82=AC=C5=93Don=C3=A2=E2=82=AC=E2=84=A2t get me wrong: I lo=
ve nuclear energy! It=C3=A2=E2=82=AC=E2=84=A2s
> > >> just that I
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> > >> it=C3=A2=E2=82=AC=E2=84=A2s wireless!=C3=A2=E2=82=AC=C2=9D
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