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-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *jay
peltz
*Sent:* Saturday, November 20, 2010 4:30 PM
*To:* al...@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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