[RE-wrenches] Shade Mitigating DC Device Application

[Mick Abraham]

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!
>
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