[RE-wrenches] Canadian Solar modules

[August Goers]

Dan -

Thanks for sharing this information - I found it an interesting read. It's always good to review the different factors which may effect module output and longevity. Only time will really tell. In quick review, it sounds to me like encapsulation materials and methods, soldering quality, cell structure, overall quality control, etc are some of the big items which will determine module longevity. I'm sure there are many more factors and details which I'm missing. As I think Bill Brooks mentioned "maybe making PV modules isn't as easy as people think..." -August  


Luminalt Energy Corporation
O: 415.564.7652
M: 415.559.1525
F: 650.244.9167

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of danrice at scinternet.net
Sent: Thursday, October 15, 2009 10:40 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Canadian Solar modules

All,

In the spirit of full disclosure, I work for Conergy in applications engineering, and we're distributors of CSI modules. (Michael, I hope I'm not out of line commenting from this perspective).

Keep in mind that CSI (Canadian Solar Inc.) is one of several manufacturers selling modules with cells made from "solar grade silicon" or Upgraded Metallurgical Grade" (UMG) silicon. UMG is a less refined product than polysilicon (not to be confused with "polycrystalline"), from which the standard monocrystalline and polycrystalline cells are produced. Cells produced from UMG silicon are known to have greater levels of impurities, which lead to a greater degree of charge recombination within the cell -meaning fewer electrons make it out of the cell to do work. Consequently, the cells have a lower power/unit area output. This is why some of the CSI modules have lower power output per unit area than comparably sized modules.

CSI also makes modules using cells produced from polysilicon, and these modules have power densities comparable to other polysilicon-cell modules.

Here's the rub with CSI: Both lines of modules -the UMG line and the Polysilicon line, use the same basic model numbers. The CS6P line of modules uses 60 6" square cells. The UMG cell modules are referred to as "e modules" in the CSI literature. Typically, the CS6P modules in the 160 - 200 watt range will be the e-modules, and the CS6P models from 200 - 230 W are the polysilicon modules. It's best to look at Canadian Solar's web site to figure out which module you're actually looking at. CSI has had some labeling issues, too, which has caused some consternation for folks using the e-modules in CA under the CSI rebate program. I understand that CSI is addressing the problem.

What I've seen of and read about UMG modules (including the CSI e-modules) suggests that there are some issues with UMG that must be addressed in order to use it as a PV cell material. Apparently, the purification processes for UMG are proprietary to the various processors making the raw materials, and making cells from UMG silicon is also a touchy process that's closely held by those making them. The types and levels of impurities vary, so purification is a moving target, and it's difficult to get a consistent product. From what I've read, UMG, because of the impurities, degrades somewhat quickly initially, then stabilizes and should remain predictably stable over the life of the module. This is reflected by CSI in their module warranty for the e-modules, which is comparable to other polysilicon modules. It is known that, due to the impurities, back-currents in UMG cells can lead to hot spots. UMG modules are less shade tolerant as a consequence. In the case of the CSI e-mod
 ules, the j-box is loaded with diodes -5, if my memory serves me. The reason is that there are fewer cells in each string within the module that's protected by a bypass diode. This is the manufacturer's way of dealing to some degree with the shade intolerance. Other module manufacturers, from what I read, are less forthright about their use of UMG cells -to their credit, CSI does not obfuscate the fact that they have a product line that uses UMG. 

I've been somewhat skeptical of UMG modules and have withheld judgement of the CSI e-modules, waiting for field results. I have but a fraction of the experience of many among this august group, and I have no need to promote product for Conergy or anybody else. What I have seen so far, among the few systems I'm monitoring, is that the CSI modules are performing to spec, and aren't failing to any significant degree. That said, the CSI e-module is intended to be a lower cost product -that's the presumed niche for UMG in the first place. Time will tell if UMG and other less expensive technologies are worth the money saved.

I hope this information is somewhat helpful. Caveat emptor. Further!

Dan Rice
Conergy and
Abundant Sun (solar) (-Bill, I got your acronym already...)

--- penobscotsolar at midmaine.com wrote:

From: penobscotsolar at midmaine.com
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Subject: Re: [RE-wrenches] Canadian Solar modules
Date: Thu, 15 Oct 2009 16:53:49 -0400 (EDT)

     We have installed about 20k of these modules, largely off grid. I
would make these recommendations:

Install on good quality mounting. We have almost exclusively been
installing these on DP&W top of pole mounts. The frames are not
particularly beefy but they are not flimsy, either, and a good mounting
system should compensate. That said, we will not use them in our Caribbean
installations due to hurricane potential.

Install where the people have plenty of room. As Tump said, these things
are doors (39 5/8 x 64 or so), but when our customers have more room than
money we install them. We installed some CSI 200's yesterday and today
installed an array of Sanyo 195's and the difference was pretty
obvious.....

    CSI panels have met the same specs and pass muster other manufacturers
have had to to achieve UL approval. They are not for everyone I
suspect, but they are meeting a niche market, are UL approved and I
think are a decent product. Perhaps in a few years I'll feel
differently but the ones we have in the field are performing well and
have been through some big winds without issues. As I said, time will
tell.......

Daryl DeJoy
Penobscot Solar Design





> "Canadian" Solar modules are most definitely made in China.
>
>
>
> I guess they couldn't get away with branding "American Solar" and probably
> didn't want "Mexican Solar." Heck, everyone likes Canadians. The "Strong
> frame" is not very rigid and flexes too much like most Chinese modules.
>
> ----- Original Message -----
>
> From: Bob-O Schultze <mailto:bob-o at electronconnection.com>
>
> To: RE-wrenches <mailto:re-wrenches at lists.re-wrenches.org>
>
> Sent: Thursday, October 15, 2009 7:48 AM
>
> Subject: Re: [RE-wrenches] Canadian Solar modules
>
>
>
> Holt,
>
> No experience with them, but I believe they are made in China. The whole
> misnomer of "Canadian Solar" is enough to turn me off to them.
>
> Bob-O
>
>
>
> On Oct 15, 2009, at 7:31 AM, <holtek at sbcglobal.net> <holtek at sbcglobal.net>
> wrote:
>
>
>
>
>
> Greatly valuing the opinions of all who participate on this list, I was
> wondering if anyone has had experience with Canadian Solar modules. Am
> bidding a 42kw system for local community college, so budgets are tight
> and
> this line of modules fits the budgetary profile. Sharing pros or cons
> would
> be greatly appreciated.
>
> _______________________________________________


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