[RE-wrenches] evergreen panels diode problems

Darryl Thayer daryl_solar at yahoo.com
Sun Sep 21 08:46:12 PDT 2008


Hi all
this all seems strange, perhaps the high positive voltage on the front of the cells causes a build up of charge attracting the negatively charged dust in the air.  Locally we have a DC power line each line either 450,000 volts either positive or Negative.  They reverse the polarity about once a month and when they do dust falls from one of the lines and the leakage current reduces.  The ground curren for this line is in the order of 100 amps? at the end of the month before reversal.  This is what i have been told by an eledctrician who works on the line.  I think the line is about 3000 amps.  
Darryl 


--- On Sat, 9/20/08, jay peltz <jay at asis.com> wrote:

> From: jay peltz <jay at asis.com>
> Subject: Re: [RE-wrenches] evergreen panels diode problems
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Date: Saturday, September 20, 2008, 8:32 PM
> HI Mark,
> 
> 
> I've seen a paper from Sunpower that shows their
> modules are OK for  
> lower voltages, but above a certain voltage ( around 200 or
> so) they  
> start to see the static build up, but interestingly only on
> the panels  
> at the high end of the voltage.
> 
> I haven't seen anything to indicate that other panels
> will see an  
> improvement with doing positive ground, if I understand
> what you are  
> saying?
> 
> But I will forward on the information to the telecom in
> question.
> 
> thanks,
> 
> jay
> 
> Peltz power
> On Sep 20, 2008, at 5:36 PM, Mark Frye wrote:
> 
> > I am sorry to hear that folks are having these kinds
> of problems.
> >
> > As I understand it, only module types made up of back
> contact cells  
> > such as
> > the SunPower are run with positive ground.
> >
> > These modules actually require positive ground to
> reduce static  
> > charge build
> > up on the front of the cell which can reverse bias and
> shut down the  
> > module.
> >
> > I don't know, but it seems to me that folks have
> somehow mixed up  
> > the high
> > yield of the back contact cell with positive grounding
> so now positive
> > grounding will increase the yeild other types of
> cells.
> >
> > Do I have the story about right?  Running front
> contact cells that  
> > have
> > plenty of collection wire on the face on a positive
> ground will not
> > significantly increase yield over a negative ground.
> >
> > Are there other benefits to running positive ground
> that I am not  
> > aware of?
> >
> > Mark Frye
> > Berkeley Solar Electric Systems
> > 303 Redbud Way
> > Nevada City,  CA 95959
> > (530) 401-8024
> > www.berkeleysolar.com
> >
> > -----Original Message-----
> > From: re-wrenches-bounces at lists.re-wrenches.org
> > [mailto:re-wrenches-bounces at lists.re-wrenches.org] On
> Behalf Of Doug  
> > Pratt
> > Sent: Saturday, September 20, 2008 5:25 PM
> > To: 'RE-wrenches'
> > Subject: Re: [RE-wrenches] evergreen panels diode
> problems
> >
> > Jay, there was a bulletin from Evergreen earlier this
> year about their
> > modules being used in positive ground systems. I
> don't remember the  
> > exact
> > details (and I'm not at work now), but the gist
> was avoid positive  
> > ground
> > till we make some modifications. Please check
> w/Evergreen on Monday.
> >
> > -Doug Pratt
> >
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