MX60 question [RE-wrenches]
Christopher Freitas --- OutBack Power
cfreitas at outbackpower.com
Tue Sep 21 17:11:32 PDT 2004
Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Give your opinion on Abortion and Win!
http://click.topica.com/caacERNbz8Qcsbz9JC9a/PermissionData
-------------------------------------------------------------------
sunwise wrote:
> Can you explain the partial shading a little better?
Performance of a partially shaded PV array is extremely variable - it
depends on the specific wiring configuration and even the orientation of
the modules themselves.
The paritally shaded condition I was referring to as being improved by
having a higher than normal PV array voltage being stepped down by a
MX60 is one in which the multiple sets of series connected panels are
getting similar shading on each individual panel or series set.
The situation most of us are familar with is one were you shade 20% or
so of the PV panel and the output drops 80% - this is caused by the
panels Vmp (voltage at max power) being lower than the battery's voltage
it is charging - you "fall" off the power curve due to the shading of a
few cells. When you start with a peak power point 2 or three times that
of the battery voltage and a MPPT type controller which can also do
step-down, then shading 20% of the PV array reduces the output by around
20% instead.
Of course things in the real world are never that simple... We are
planning to use our matched PV arrays here at OutBack to do some testing
of different shading conditions to see what the impacts are... stay
tuned again!
Christopher Freitas
OutBack Power Systems, Inc.
cfreitas @ outbackpower.com
www.outbackpower.com
Arlington WA USA
Tel 360 435 6030
Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Do you love your country? Get a Free USA T SHIRT click here to
receive your gift.
http://click.topica.com/caacDvPbz8Qcsbz9JC9f/PermissionData
-------------------------------------------------------------------
- - - -
To send a message: RE-wrenches at topica.com
Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read
List rules & etiquette: www.mrsharkey.com/wrenches/etiquete.htm
Check out participant bios: www.mrsharkey.com/wrenches/
Hosted by Home Power magazine
Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael.welch at homepower.com
EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com
For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------
More information about the RE-wrenches
mailing list