[RE-wrenches] Positive-ground question re Sunpower

boB Gudgel boB at midnitesolar.com
Sat Nov 20 17:14:05 PST 2010


On 11/20/2010 4:36 PM, Mark Frye wrote:
> From the 2006 white paper:
> *
>
> "Polarization
>
> *
>
> Incorrect grounding of SunPower modules can inducea surface charge 
> which would lower the energyproduction. Previously SunPower has 
> announced the
>
> discovery of the "surface polarization" effect which creates
>
> a non-destructive and reversible accumulation of static
>
> charge on the surface of high-efficiency solar cells such as
>
> SunPower's A-300 cells [9]. When the cells have a high
>
> positive voltage with respect to ground,
>

How high though ??  I would think that there might be some
curve that might show how high of V produces  how much degradation ?

I assume that the lower voltage modules in the string work better ??

Maybe it's the other way around and the high voltage modules work better
when in a positive grounded system ?

> a negative static
>
> charge is built up on the surface of the cell due to current
>
> leakage through the glass and the highly insulating front
>
> surface anti-reflection coating of the cell.
>

I bet (or hope) that they fix this some day by changing the composition of
the glass, slightly, maybe.

Nobody seems to talk about this except for this one paper that we see.

boB

> This negative
>
> static charge causes increased surface recombination and
>
> the performance of the module is reduced. If the polarity
>
> is reversed and the cells are highly negative with respect
>
> to ground, the negative static charge is replaced by a
>
> positive static charge which restores the module
>
> performance."
>
>
> Mark Frye
> Berkeley Solar Electric Systems
> 303 Redbud Way
> Nevada City,  CA 95959
> (530) 401-8024
> _www.berkeleysolar.com_ <http://www.berkeleysolar.com/>
>
>
> ------------------------------------------------------------------------
> *From:* re-wrenches-bounces at lists.re-wrenches.org 
> [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *jay 
> peltz
> *Sent:* Saturday, November 20, 2010 4:30 PM
> *To:* Allan at positiveenergysolar.com; RE-wrenches
> *Subject:* Re: [RE-wrenches] Positive-ground question re Sunpower
>
> Hi Allan,
>
> I have seen the white paper from Sunpower, ( but don't have a copy) 
> that shows the losses as the voltage rises if using neg ground.
>
> But from memory, if using at low voltages such as two in series there 
> should be minimal if any "loss" of watts.
> If you could use them as singles, for say a 12v system then there is 
> no loss.
>
> Jay
>
> Peltz power
>
>
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