Sunny Boy upgrade question [RE-wrenches]

[Bill Brooks]

Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Get $1000.00 Overnight! Fast and Easy!
No Credit Checks! Many Lenders are 100% Paperless!
Let The Wizard Find the right Lender for you!
http://click.topica.com/caadOutbz8Qcsbz9JC9a/911PaydayAdvance
-------------------------------------------------------------------

Allan,

The  BP 3160 is the silicon nitride anti-reflective coated version of the
SX140. The temperature coefficient is identical. 6 or 7 volts of max power
differential is not all that critical. It is not an ideal arrangement, but
anything you do with this array will not be perfect. See if you can find
some 3150 modules instead of the 3160's. They would just be lower spec 160s.
They may not prominently display these modules on their website, but I bet
they have some. They are on their spec sheet. I wouldn't go to the 3170
because the voltage specs are getting up there on voltage and you are not
going to get the performance that you would get out of 150s or 160s
(essentially you would be buying 170s and getting 150s worth of power). If
you're curious about operating points, use the Maui software to produce IV
curves for normal temperature operation. I think you'll be just fine--just
don't make a habit of it. 

Given the way modules are changing so rapidly these days, you are lucky to
still have modules with the same form factor. The color will be slightly
different due to the silicon nitride, but that's not too big a deal. The
lesson to learn here is size your inverter to your array and do not count on
being able to upgrade down the road. It is better to match inverters and
arrays as you go if you can. The saving grace these days is that inverter
efficiency curves are so good down to 10% power, that if you were guaranteed
identical modules in the future, installing half of an array is not nearly
as evil as it used to be with the old Omnion inverters that were at 60%
efficiency at 10% power.

Bill.

-----Original Message-----
From: Allan Sindelar [mailto:allan at positiveenergysolar.com] 
Sent: Wednesday, August 31, 2005 7:22 PM
To: New wrenches posting
Subject: Sunny Boy upgrade question [RE-wrenches]


Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Is your computer freezing up or slowing down?
Repair corrupt files and harmful errors - protect your PC
Take a 2-minute PC health check-up at no charge!
http://click.topica.com/caadOuabz8QcsbaaVcJa/PC PowerScan
-------------------------------------------------------------------

Esteemed Wrenches,
How would you solve this? Two years ago we installed a batteryless system
with a Sunny Boy 1800 and seven BP SX140s, with racks in place for a second
7-module array in the future, when the client could afford it. (This is the
client that was featured in the RE Financing article in HP103:97, who
financed his system through the Permaculture Credit Union.)

He's ready to add the second row of seven modules now, and SX140s are no
longer available. We can get 160s and 170s, I think. I would expect that as
long as the MPP voltage is closely aligned (it's close but not perfect, 34V
vs. 35 at mpp), and the cell type is similar (it is, polycrystalline), it
should be OK to mix outputs, as the two strings are in parallel and combine
prior to the inverter.

Any thoughts on this are welcome.

Allan at Positive Energy

Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Is your computer freezing up or slowing down?
Repair corrupt files and harmful errors - protect your PC
Take a 2-minute PC health check-up at no charge!
http://click.topica.com/caadUl2bz8QcsbaaVcJf/PC PowerScan
-------------------------------------------------------------------

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & how to change your email address:
www.mrsharkey.com/wrenches/etiquette.php

Check out participant bios: www.mrsharkey.com/wrenches/

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com

Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Are you a lottery player?Play smarter! Improve your 
odds  and detect winning patterns. Access the best 
kept lottery secret on the Net. Easy to use!
http://click.topica.com/caadUmEbz8Qcsbz9JC9f/Lottery Vault 
-------------------------------------------------------------------

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & how to change your email address: www.mrsharkey.com/wrenches/etiquette.php

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
--^----------------------------------------------------------------