[RE-wrenches] Sunpower modules

[Brian Teitelbaum]

Drake,

One thing about those old modules is that the cells are incredibly thick. You can feel them on the back-sheet. They must be at least 1/16" thick. Wire-saw technology was just not that good in the old days. Module manufacturers say that the thickness of the cell has no effect on performance, but I guess we will just have to see. If we're still around in 2036, we can compare a set of 2009 modules with my old ones which will be 54 by then!

Brian


-----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
Sent: Friday, March 20, 2009 1:07 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Sunpower modules

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
>
>