[RE-wrenches] Sunpower modules

[Drake Chamberlin]

Allan and Brian

Thanks for the answer to the problem.  I think the Xantrex PWM 
chargers are going to be the most appropriate for these modules.

The old Arco modules are incredibly long lasting.  I hope the ones we 
are putting in today will last as long.

Drake

At 01:40 PM 3/20/2009, you wrote:
>Drake,
>
>Just to add to Allan's excellent post, most of the Arco's made 
>before about 1985 had less than 36 cells. Some were 35-cell, most 
>were 33-cell, but there were also 32 and 30-cell units.
>
>You might want to look into rewiring the modules in higher voltage 
>series strings to get more "oomph" out of the MPPT controller, and 
>reduce transmission losses. However, be aware that many of those old 
>Arco modules had a sticker on them that said something like "do not 
>operate above 50VDC"
>
>I still have 12 Arco, 33-cell, model 16-2000 modules (16Vmp/2A) on 
>my off-grid house, wired in pairs for 24V and going through an 
>ancient Trace C-30A relay controller (not even PWM!). I've 
>contemplated wiring them for 36V and using MPPT, and I may someday, 
>but they have been working so well as is that I haven't bothered. 
>Even on hot days I often see 27.5V and 11-12A charging my 24V 
>battery bank, which I think is damn good performance from a set of 
>27-year-old modules.
>
>Brian Teitelbaum
>AEE Solar
>
>
>
>-----Original Message-----
>From: re-wrenches-bounces at lists.re-wrenches.org 
>[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Allan Sindelar
>Sent: Friday, March 20, 2009 8:32 AM
>To: 'RE-wrenches'
>Subject: Re: [RE-wrenches] Sunpower modules
>
>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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Drake Chamberlin
Athens Electric
OH License 44810
CO License 3773
740-448-7328
740-856-9648