[RE-wrenches] DunPower modules

[Bill Brooks]

Jeff,

 

Although some of what you say is true-and anyone allowed to install SunPower
modules should be intimately aware of the positive grounding
requirement-they actually can be installed on ungrounded and bi-polar arrays
with the inclusion of some wiz-bang depolizerinators ;-).

 

Bottom line is that they are good modules, but like anything in PV system
design-you have to know what you are doing. Learning through mistakes is
painful. I know-I have over 20 years of pain to remind me.

 

Bill.

 

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Jeff Irish
Sent: Friday, March 20, 2009 1:49 PM
To: re-wrenches at lists.re-wrenches.org
Subject: Re: [RE-wrenches] SunPower modules

 

Word of caution. don't wire the bigger SunPower modules with the negative
conductor grounded.  With the metal frame grounded, as it should be, this
combination causes a strange surface polarization effect that will discolor
the cells and cause the power output to drop by about half.  Fortunately the
polarization and discoloring are totally reversible if the system is
re-wired with the positive conductor grounded (as we found out, even after 6
months of being wired incorrectly), but it takes a few days to correct.  For
this same reason, SunPower modules can't be used with bipolar inverters.

 

Jeff Irish

Hudson Valley Clean Energy

 

  _____  

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of jay peltz
Sent: Friday, March 20, 2009 9:39 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Sunpower modules

 

Hi Larry,

 

 I was under the impression that Sunpower were only for on grid?

 

And for off grid with the low voltages that we use, they are still requiring
you to use positive ground?  I've seen the white paper they did and it
showed at lower voltages there is no need to positive ground, thats why for
example those 90 watt panels using Sunpower cells are used with Negative
ground.

 

curious,

 

jay

 

peltz power

On Mar 19, 2009, at 9:14 PM, Larry Crutcher, Starlight Solar wrote:

 

William,

 

I know you asked Jeff but thought I would respond as all we do are off grid,
battery based systems. I typically see that the Vmp voltage of Sunpower
modules is closer to spec with than with Kyocera, Sharp or Mitsubishi. In my
opinion Sunpower modules are only surpassed by Sanyo. I realize this is
anecdotal but after hundreds of installs you begin to notice these things.

 

Larry Crutcher

 

On Mar 19, 2009, at 5:46 PM, William Miller wrote:

 

Jeff:

Have these modules worked for you in battery based systems?

William Mill


At 01:27 PM 3/19/2009, you wrote:



Hiya Jeff,
You are correct that the sunpower modules are positively grounded.  You are
also correct that sunpower only deals with dedicated "dealers".  That means
that if you are not one of their dealers you cannot get their panels.  It is
my understanding that sunpower is always looking for new dealers, so you may
want to check in with them.  As far as architectural review committees and
such, we have never had a problem using SPR modules in the areas where
review is an issue.  The positive ground really does not affect aanything.
Instead of your negative wire being the grounded (white) conductor it is
your positive conductor that is grounded.  This means you are switching the
negative instead of the positive in the DC disco.  Sunpower sells packaged
systems, so they provide positive ground inverters from different
manufacturers.

Evergreen now has a black framed module, and I believe Sharp does too.  I
hope this helps, any other questions feel free to contact me.  
Jeff Blick
Lead PV Installer

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