[RE-wrenches] Positive-ground question re Sunpower

[Brian Teitelbaum]

boB,

There is a chart in that white paper that graphs the losses on each module in the string. No significant losses seem to occur until you get to 5 in series

I can send the whole paper to you, or anyone, off list if you are interested

Brian Teitelbaum
AEE Solar
bteitelbaum at aeesolar.com

From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of boB Gudgel
Sent: Saturday, November 20, 2010 5:14 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Positive-ground question re Sunpower

On 11/20/2010 4:36 PM, Mark Frye wrote:
>From the 2006 white paper:

"Polarization

Incorrect grounding of SunPower modules can induce a surface charge which would lower the energy production. 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> [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<mailto: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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