[RE-wrenches] Sunpower modules

Allan Sindelar allan at positiveenergysolar.com
Fri Mar 20 08:31:55 PDT 2009


Drake,
The key to your question may be in the "old Arco units". Most Arcos (all
predate 1990, when Siemens bought Arco) are 36 cell, but both Arco and
Solarex made some 33-cell, 32-cell, and even 30-cell "self-regulating"
modules in those years. With fewer cells, the MPPT was too low to benefit
much from Boost technology. 

I have one customer with Arco M52L "Tri-Lams" and another with 32-cell
Solarexes. In both cases I had recommended upgrade to MPPT, but when I saw
what modules they had, I told them not to go ahead with the upgrade, as it
wouldn't be cost-effective.

Allan Sindelar
allan(at)positiveenergysolar.com
NABCEP Certified Solar PV Installer
Positive Energy, Inc.
3201 Calle Marie
Santa Fe NM 87507
505 424-1112
www.positiveenergysolar.com

Please consider the environment before printing this e-mail. 

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Drake
Chamberlin

At 09:46 AM 3/20/2009, you wrote:
>The CTI-90, rated at 5.15 amps, will reach 7 amps here in Yuma with 
>the Blue Sky 3024i.

Do you use the Blue Sky metering, or have you checked the MPPT output 
with independent metering?  I retrofitted a 12 V Blue Sky charger on 
an old cabin system. The CC had no on-board metering.  My measured 
result showed almost the same output and input on a cool, sunny 
day.  The modules were ancient Arco units, but I still expected some 
improvement.

Drake Chamberlin




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