[RE-wrenches] Matching modules into Xantrex GT

Peter Parrish peter.parrish at calsolareng.com
Sat Jan 15 14:09:09 PST 2011


A typo. See below:

Here is the way I figure this kind of problem out.

(1) Old modules. Figure out the number of cells and the cell size. For
example 72 cells, 100 mm (4”) square.

(2) New module. If you can, find a module with the same number of cells (not
modules!) and same cell size.

(3) Make sure were are talking the same PV Cell material (crystalline Si,
poly or single)

To first order, the two modules should have nearly the same characteristics:
Voc, Isc, Vmp and Imp. You should be able to build a new string with the
same number of modules. Caveat: older modules will show lower Isc due to the
fact that there have been significant advances in surface treatment (AR
coating, surface etching) and in the case of poly special treatment of the
wafer (heat treatment plus H2 gas?).

Failing that, try to match up total number of cells in the string, keeping
cell size the same. I don’t have the SW data at hand but it doesn’t look
like they are a good match.

Don’t give up on SW175s. There may be someone who has some lying around or
the precursor Shell Solar 175-PC. You might have to fixture them with new
connectors. 

- Peter

Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parrish at calsolareng.com  
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885

 
________________________________________
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of William
Miller
Sent: Saturday, January 15, 2011 10:51 AM
To: RE-wrenches
Subject: [RE-wrenches] Matching modules into Xantrex GT

Friends:

I have a client with a Xantrex GT2.8 inverter.  Feeding it are 8 Solar World
SW175 modules.  This is half the modules that this inverter can handle.  The
client wants to realize the full potential of this inverter.  Adding 8
additional SW175 modules would be ideal, but they are no longer
manufactured.

I need to find a group of modules to match the 175s.  I am contemplating 9
SW240s.  The specifications for this match up are below.  I imagine the IV
curves are similar for these two modules as they are the same chemistry and
the same manufacturer.

        8-SW175 9-SW240
Voc     403             382
Vmp     283             275
Imp     4.95            7.87
Pcsi    1252            1715
Ptotal  2.967

Might this match be close enough?  I know this over-powers the inverter
slightly.  I imagine that the Xantrex will self regulate this very rare over
wattage condition.

Comments?

William Miller




Please note new e-mail address and domain:

William Miller 
Miller Solar
Voice :805-438-5600
email: william at millersolar.com
http://millersolar.com
License No. C-10-773985




More information about the RE-wrenches mailing list