Solar module cell-count [RE-wrenches]

[Joel Davidson]

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Just two months ago I answered an ad on the matchbook cover and now I are a 
photovoltaic system designer. The pay's not good, but it's better than being 
a veterinary assistance and cleaning out cages.

----- Original Message ----- 
From: "Bill Brooks" <bill at brooksolar.com>
To: <RE-wrenches at topica.com>
Sent: Thursday, May 24, 2007 5:02 PM
Subject: RE: Solar module cell-count [RE-wrenches]


>
> Joel,
>
> Design is so routinely oversimplified that our industry seems to suggest
> that someone with 2 months of experience can design PV systems. It's just
> not true.
>
> Bill Brooks, PE
> Brooks Engineering
> 873 Kells Circle
> Vacaville, CA 95688
> office and mobile phone: 707-332-0761
> fax:707-451-7739
> email: billbrooks7 at yahoo.com
> web: www.brooksolar.com
>
> Ecclesiastes 11:7 Light is sweet, and it pleases the eyes to see the sun.
>
>
>> -----Original Message-----
>> From: Joel Davidson [mailto:joel.davidson at sbcglobal.net]
>> Sent: Tuesday, May 22, 2007 7:22 AM
>> To: RE-wrenches at topica.com
>> Subject: Re: Solar module cell-count [RE-wrenches]
>>
>>
>> > (Topica has been flaky lately so I'll try sending this a 4th time.)
>> >
>> >> Bill,
>> >>
>> >> Thanks for your input. 6-inch polycrystalline cell 36, 54 and 60-cell
>> >> modules are available. Bob-O (thanks) says different cell
>> configurations
>> >> can
>> >> be used for battery based PV systems thanks to MPPT controllers. Andy
>> >> Riegler (thanks) says Xantrex inverters with 300 to 600 VDC input have
>> an
>> >> MPPT sweet spot around 30% above 300 volts (for example 21 each 
>> >> Kyocera
>> >> KC130 modules which is 756 cells). The SMA Central also likes 21 each
>> 6"
>> >> cell 36-cell modules. Although PV modules have no moving parts, there
>> >> sure
>> >> are a lot of PV system design "moving parts."
>> >>
>> >> Happy designing.
>> >> Joel Davidson
>> >>
>> >>
>> >> ----- Original Message -----
>> >> From: "Bill Brooks" <bill at brooksolar.com>
>> >> To: <RE-wrenches at topica.com>
>> >> Sent: Thursday, May 17, 2007 4:46 PM
>> >> Subject: RE: Solar module cell-count [RE-wrenches]
>> >>
>> >>
>> >>>
>> >>> Joel,
>> >>>
>> >>> A key to better system design is not directly cell count. Higher cell
>> =
>> >>> counts make it more difficult to maximize dc voltage into an inverter
>> >>> since
>> >>> = each module step is so large. Lower cell counts necessitate larger
>> >>> cells
>> >>> so = that wiring costs are reduced. For larger scale projects, it
>> would
>> >>> be
>> >>> nice to have 6" to 8" cells so that each string has the highest
>> possible
>> >>> current = and voltage therefore getting the most power per labor
>> dollar.
>> >>>
>> >>> Smaller rooftops necessitate smaller cells so that the designer can
>> get
>> >>> =
>> >>> more voltage per smaller area. Therefore, big systems need big cells
>> and
>> >>> =
>> >>> small residential systems need smaller cells.
>> >>>
>> >>> Everyone seems to talk about module power and cell count, but they =
>> >>> rarely
>> >>> discuss the issue of cell size and current. That's my story, and I'm
>> >>> sticking to it.
>> >>>
>> >>> Bill.
>> >>>
>> >>> Bill Brooks, PE
>> >>> Brooks Engineering
>> >>> 873 Kells Circle
>> >>> Vacaville, CA 95688
>> >>> office and mobile phone: 707-332-0761
>> >>> fax:707-451-7739
>> >>> email: billbrooks7 at yahoo.com
>> >>> web: www.brooksolar.com
>> >
>>
>>
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>>
>
>
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> Archive of previous messages: 
> http://lists.topica.com/lists/RE-wrenches/read
>
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> 


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