[RE-wrenches] Shade Mitigating DC Device Application (Matt Lafferty)

Thu Oct 29 06:06:08 PDT 2009

The original rhyme was in the direction,
of Sunny Island; I sense an election
to factor some batteries into the mix.
Batteries would alter the technology fix.

William addresses the western hill,
but seems to exclude the battery pill.
So, what is it, Matt, kindly decipher,
if batteries are out or in this case, to die for.

Mick Abraham, Proprietor
www.abrahamsolar.com

Voice: 970-731-4675

On Thu, Oct 29, 2009 at 12:58 AM, William Korthof <wkorthof at eesolar.com>wrote:

> Why bother with the DC converters if you only have 2 strings?
>
> Get a wide-range, dual-channel inverter (Power One 5000) and plug in the
> modules
> however you like. The bypass diodes in the modules will bypass the shaded
> module
> sections as appropriate for the conditions, and rest of the modules (not
> shaded) will
> contribute power used by the wide-input MPPT at the optimal string voltage.
> The input channels are separately controlled, so they both operate at their
> optimal
> MPPT voltage at all times.
>
> The input voltage range is extremely wide, 90 to 550 Vdc (Mppt), with a
> startup
> voltage of 200 Vdc and a maximum Voc of 600 Vdc. That's extremely flexible
> gets
> you very close to harvesting 100% of the available module output.
>
> Cost, performance, and reliability seem far better with a PV/inverter
> combination
> than what you get if you add DC converters to each module.
>
> /wk
>
>
>
>> Date: Wed, 28 Oct 2009 16:29:56 -0700
>> From: Matt Lafferty <gilligan06 at gmail.com>
>> To: "RE Wrenches" <re-wrenches at lists.re-wrenches.org>
>> Subject: [RE-wrenches] Shade Mitigating DC Device Application
>> Message-ID: <F3827D62F9FA4F1E983C525A44F44CE8 at GILLIGONE>
>> Content-Type: text/plain; charset="us-ascii"
>>
>> Esteemed Wrenches,
>>
>> Your collective wisdom & conjecture is sought in resolving the following
>> riddle:
>>
>> There once was a home in the hills.
>> With morning sun the roof is filled.
>> Blasted mountain rising in the west,
>> Makes a shady mess at very best.
>>
>> "Onward! Fear not!", sayeth the man.
>> "Twenty-four modules. Not one less!"
>> "Black box of magic for every one."
>> "And string inverter plus Island of Sun!"
>>
>> With fifty-one hundred watts of DC.
>> Two series strings of four times three.
>> Black boxes of magic, but not by that name.
>> At quarter the price are they really the same?
>> 'Tis not the matter, least not today.
>> To you the group... What do you say?
>>
>> For greatest performance over time to yield...
>> 2 balanced strings of shade and of sun,
>> Or put worst shade all onto one?
>> Snake-oil merchants say not to worry.
>> Magical boxes change dark to light in a hurry.
>> What say ye, from out in the field?
>> Balance the strings, or not?
>> <End>
>>
>> Some factors to consider.... The site is shade-challenged, primarily in
>> the
>> afternoon. There will be two strings of 12 modules each feeding a single
>> inverter. Enphase is off the table for now. Homeowner specifically wants
>> to
>> do back-of-module DC shade mitigation. The array layout is such that
>> configuring the strings so there is a dominant sunny one and dominant
>> shady
>> one is possible. It is also possible and almost as easy to configure the
>> strings so they are more balanced with each other. Assuming that each
>> module
>> is equipped with a black box, will it make any difference which
>> configuration gets used?
>>
>> I have my theory on the subject and am interested in yours. Thanks in
>> advance for any and all feedback.
>>
>> Pray for Sun!
>> -------------- next part --------------
>> An HTML attachment was scrubbed...
>> URL: <
>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20091028/7546620a/attachment-0001.htm
>> >
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Wed, 28 Oct 2009 18:21:14 -0600
>> From: Mick Abraham <mick at abrahamsolar.com>
>> To: gilligan06 at gmail.com, RE-wrenches
>>        <re-wrenches at lists.re-wrenches.org>
>> Subject: Re: [RE-wrenches] Shade Mitigating DC Device Application
>> Message-ID:
>>        <3dff9f8c0910281721r3a729f1er48806fe6aa5a1cba at mail.gmail.com>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>> This jester must ask, with a hint of glee...
>> is this off the grid, or is there u-til-i-tee?
>>
>> Mick Abraham, Proprietor
>> www.abrahamsolar.com
>>
>> Voice: 970-731-4675
>>
>>
>> On Wed, Oct 28, 2009 at 5:29 PM, Matt Lafferty <gilligan06 at gmail.com>
>> wrote:
>>
>>  Esteemed Wrenches,
>>>
>>> Your collective wisdom & conjecture is sought in resolving the following
>>> riddle:
>>>
>>> There once was a home in the hills.
>>> With morning sun the roof is filled.
>>> Blasted mountain rising in the west,
>>> Makes a shady mess at very best.
>>> **
>>> *"Onward! Fear not!*",* *sayeth the man.
>>> *"Twenty-four modules. Not one less!"*
>>> *"Black box of magic for every one."*
>>> *"And string inverter plus Island of Sun!"*
>>>
>>> With fifty-one hundred watts of DC.
>>> Two series strings of four times three.
>>> Black boxes of magic, but not by that name.
>>> At quarter the price are they really the same?
>>> 'Tis not the matter, least not today.
>>> To you the group... What do you say?
>>>
>>> For greatest performance over time to yield...
>>> 2 balanced strings of shade and of sun,
>>> Or put worst shade all onto one?
>>> Snake-oil merchants say not to worry.
>>> Magical boxes change dark to light in a hurry.
>>> What say ye, from out in the field?
>>> Balance the strings, or not?
>>> <End>
>>>
>>> Some factors to consider.... The site is shade-challenged, primarily in
>>> the
>>> afternoon. There will be two strings of 12 modules each feeding a single
>>> inverter. Enphase is off the table for now. Homeowner specifically wants
>>> to do back-of-module DC shade mitigation. The array layout is such that
>>> configuring the strings so there is a dominant sunny one and dominant
>>> shady
>>> one is possible. It is also possible and almost as easy to configure the
>>> strings so they are more balanced with each other. Assuming that each
>>> module
>>> is equipped with a black box, will it make any difference which
>>> configuration gets used?
>>>
>>> I have my theory on the subject and am interested in yours. Thanks in
>>> advance for any and all feedback.
>>>
>>> Pray for Sun!
>>>
>>> _______________________________________________
>>> List sponsored by Home Power magazine
>>>
>>> List Address: RE-wrenches at lists.re-wrenches.org
>>>
>>> Options & settings:
>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>>
>>> List-Archive:
>>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>>
>>> List rules & etiquette:
>>> www.re-wrenches.org/etiquette.htm
>>>
>>> Check out participant bios:
>>> www.members.re-wrenches.org
>>>
>>>
>>>
>>>  -------------- next part --------------
>> An HTML attachment was scrubbed...
>> URL: <
>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20091028/561affab/attachment.htm
>> >
>>
>> ------------------------------
>>
>> _______________________________________________
>> List sponsored by Home Power magazine
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Options & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>> List-Archive:
>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>
>> List rules & etiquette:
>> www.re-wrenches.org/etiquette.htm
>>
>> Check out participant bios:
>> www.members.re-wrenches.org
>>
>>
>>
>> End of RE-wrenches Digest, Vol 2, Issue 1107
>> ********************************************
>>
>
> Bring back the EV1 electric car!
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20091029/79dcf1ba/attachment-0004.html>