[RE-wrenches] mix-n-match Unisolar

[Bill Brooks]

Geoff,

 

The ultimate issue is how many cells are in each series string and is the
voltage of the cells nearly the same. As long as the number and the voltage
of the cells match up for each string, it makes no difference what
arrangement the modules are in.

 

You could have 5 + 6 + 7 = 18 cells in one group and 3+10+5 =18 cells in
another group, and its all good as long as they are similar cells. Unisolar,
due to the low fill factor, is actually pretty forgiving of difference
modules and cells. If you need help, let me know.

 

Bill.

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Jason
Lombard
Sent: Friday, October 31, 2008 8:55 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] mix-n-match Unisolar

 

You are correct and they are not. The entire string or array will drop the
lowest performing panel and seriously detain performance.

On Thu, Oct 30, 2008 at 2:29 PM, Geoff Greenfield <geoff at third-sun.com>
wrote:

I thought I knew the answer to this one, but wanted to run it by the list.

 

We are responding to a bid where the electrical engineer has designed a
system with different sized Uni-solar laminates in some series strings
paralelled with consistant full size strings.  (this was done to work around
skylights etc).

 

We suggested that this was a poor design and will lead to "least common
denomenator" performance, exacerbated by MPPT confusion.  The EE responded
that "the bypass diodes allow for this".

 

Any experience with this in practice?

For a brighter energy future,

Geoff Greenfield
Founder and CEO
Third Sun Solar & Wind Power Ltd.
340 West State Street, Unit 25
Athens, OH 45701

740.597.3111     Fax 740.597.1548
www.Third-Sun.com

Clean Energy - Expertly Installed




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-- 
Jason Lombard
Open Hand Solar LLC.
HC74 Box13
Pecos, NM. 87552
505 795 8646

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