The original rhyme was in the direction,<br>of Sunny Island; I sense an election<br>to factor some batteries into the mix.<br>Batteries would alter the technology fix.<br><br>William addresses the western hill,<br>but seems to exclude the battery pill.<br>
So, what is it, Matt, kindly decipher,<br>if batteries are out or in this case, to die for.<br><br clear="all">Mick Abraham, Proprietor<br><a href="http://www.abrahamsolar.com">www.abrahamsolar.com</a><br><br>Voice: 970-731-4675<br>
<br><br><div class="gmail_quote">On Thu, Oct 29, 2009 at 12:58 AM, William Korthof <span dir="ltr"><<a href="mailto:wkorthof@eesolar.com">wkorthof@eesolar.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Why bother with the DC converters if you only have 2 strings?<br>
<br>
Get a wide-range, dual-channel inverter (Power One 5000) and plug in the modules<br>
however you like. The bypass diodes in the modules will bypass the shaded module<br>
sections as appropriate for the conditions, and rest of the modules (not shaded) will<br>
contribute power used by the wide-input MPPT at the optimal string voltage.<br>
The input channels are separately controlled, so they both operate at their optimal<br>
MPPT voltage at all times.<br>
<br>
The input voltage range is extremely wide, 90 to 550 Vdc (Mppt), with a startup<br>
voltage of 200 Vdc and a maximum Voc of 600 Vdc. That's extremely flexible gets<br>
you very close to harvesting 100% of the available module output.<br>
<br>
Cost, performance, and reliability seem far better with a PV/inverter combination<br>
than what you get if you add DC converters to each module.<br>
<br>
/wk<br>
<br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br>
Date: Wed, 28 Oct 2009 16:29:56 -0700<br>
From: Matt Lafferty <<a href="mailto:gilligan06@gmail.com" target="_blank">gilligan06@gmail.com</a>><br>
To: "RE Wrenches" <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>><br>
Subject: [RE-wrenches] Shade Mitigating DC Device Application<br>
Message-ID: <F3827D62F9FA4F1E983C525A44F44CE8@GILLIGONE><br>
Content-Type: text/plain; charset="us-ascii"<br>
<br>
Esteemed Wrenches,<br>
<br>
Your collective wisdom & conjecture is sought in resolving the following<br>
riddle:<br>
<br>
There once was a home in the hills.<br>
With morning sun the roof is filled.<br>
Blasted mountain rising in the west,<br>
Makes a shady mess at very best.<br>
<br>
"Onward! Fear not!", sayeth the man.<br>
"Twenty-four modules. Not one less!"<br>
"Black box of magic for every one."<br>
"And string inverter plus Island of Sun!"<br>
<br>
With fifty-one hundred watts of DC.<br>
Two series strings of four times three.<br>
Black boxes of magic, but not by that name.<br>
At quarter the price are they really the same?<br>
'Tis not the matter, least not today.<br>
To you the group... What do you say?<br>
<br>
For greatest performance over time to yield...<br>
2 balanced strings of shade and of sun,<br>
Or put worst shade all onto one?<br>
Snake-oil merchants say not to worry.<br>
Magical boxes change dark to light in a hurry.<br>
What say ye, from out in the field?<br>
Balance the strings, or not?<br>
<End><br>
<br>
Some factors to consider.... The site is shade-challenged, primarily in the<br>
afternoon. There will be two strings of 12 modules each feeding a single<br>
inverter. Enphase is off the table for now. Homeowner specifically wants to<br>
do back-of-module DC shade mitigation. The array layout is such that<br>
configuring the strings so there is a dominant sunny one and dominant shady<br>
one is possible. It is also possible and almost as easy to configure the<br>
strings so they are more balanced with each other. Assuming that each module<br>
is equipped with a black box, will it make any difference which<br>
configuration gets used?<br>
<br>
I have my theory on the subject and am interested in yours. Thanks in<br>
advance for any and all feedback.<br>
<br>
Pray for Sun!<br>
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<br>
Message: 3<br>
Date: Wed, 28 Oct 2009 18:21:14 -0600<br>
From: Mick Abraham <<a href="mailto:mick@abrahamsolar.com" target="_blank">mick@abrahamsolar.com</a>><br>
To: <a href="mailto:gilligan06@gmail.com" target="_blank">gilligan06@gmail.com</a>, RE-wrenches<br>
<<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>><br>
Subject: Re: [RE-wrenches] Shade Mitigating DC Device Application<br>
Message-ID:<br>
<<a href="mailto:3dff9f8c0910281721r3a729f1er48806fe6aa5a1cba@mail.gmail.com" target="_blank">3dff9f8c0910281721r3a729f1er48806fe6aa5a1cba@mail.gmail.com</a>><br>
Content-Type: text/plain; charset="iso-8859-1"<br>
<br>
This jester must ask, with a hint of glee...<br>
is this off the grid, or is there u-til-i-tee?<br>
<br>
Mick Abraham, Proprietor<br>
<a href="http://www.abrahamsolar.com" target="_blank">www.abrahamsolar.com</a><br>
<br>
Voice: 970-731-4675<br>
<br>
<br>
On Wed, Oct 28, 2009 at 5:29 PM, Matt Lafferty <<a href="mailto:gilligan06@gmail.com" target="_blank">gilligan06@gmail.com</a>> wrote:<br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Esteemed Wrenches,<br>
<br>
Your collective wisdom & conjecture is sought in resolving the following<br>
riddle:<br>
<br>
There once was a home in the hills.<br>
With morning sun the roof is filled.<br>
Blasted mountain rising in the west,<br>
Makes a shady mess at very best.<br>
**<br>
*"Onward! Fear not!*",* *sayeth the man.<br>
*"Twenty-four modules. Not one less!"*<br>
*"Black box of magic for every one."*<br>
*"And string inverter plus Island of Sun!"*<br>
<br>
With fifty-one hundred watts of DC.<br>
Two series strings of four times three.<br>
Black boxes of magic, but not by that name.<br>
At quarter the price are they really the same?<br>
'Tis not the matter, least not today.<br>
To you the group... What do you say?<br>
<br>
For greatest performance over time to yield...<br>
2 balanced strings of shade and of sun,<br>
Or put worst shade all onto one?<br>
Snake-oil merchants say not to worry.<br>
Magical boxes change dark to light in a hurry.<br>
What say ye, from out in the field?<br>
Balance the strings, or not?<br>
<End><br>
<br>
Some factors to consider.... The site is shade-challenged, primarily in the<br>
afternoon. There will be two strings of 12 modules each feeding a single<br>
inverter. Enphase is off the table for now. Homeowner specifically wants<br>
to do back-of-module DC shade mitigation. The array layout is such that<br>
configuring the strings so there is a dominant sunny one and dominant shady<br>
one is possible. It is also possible and almost as easy to configure the<br>
strings so they are more balanced with each other. Assuming that each module<br>
is equipped with a black box, will it make any difference which<br>
configuration gets used?<br>
<br>
I have my theory on the subject and am interested in yours. Thanks in<br>
advance for any and all feedback.<br>
<br>
Pray for Sun!<br>
<br>
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