Contamination under glass? (PV panels) - Page 2

Sun Dandan · 11-20-11, 06:58 PM

Hi,
I'm a student from Singapore.
We have seen something like this before. And we are actually studying on this. We call it 'crack-shadow' or 'snail-trail'.
The root causes of these stains/contamination/marks are not yet found.
Could you tell me everything about your PV system?

--> When did you buy those modules? Are those modules first-hand? What brand are those? When did you first see those stains and when is the last inspection?
--> Weather/climate conditions. Any storm? High-Low temp? Humidity and such.
--> Is there notable power drop? If yes, how much is the power drop.
--> Have you done any test for those modules? Is there any hotspot when those panels operate?

And could you take some pictures of the back of your PV panels? Any wrinkle on the backsheet of your pannels?

Xringer · 11-20-11, 08:18 PM

I got them brand new. They were shipped from the importer
Solar Panels -Buy Solar Panels from SOLARTECH POWER Complete Solar Panels Solution
The marks were seen when they were unpacked (the first day).

The back side of the panels seem to be perfect.

There are more pics here.. Solar pictures by Xringer - Photobucket

These panels have never really been good performers.
Under idea conditions, they might put out 100w (instead of their rated 125w).

My 200w Canadian Solar CS6P-200 panels (also made in China) work much better.
With a well matched load, they will always put out 200w under most sun and temperature conditions.

The importer offered to replace the 125w panels, but I didn't want to ship them
3,000 miles and hope to get back four new panels that would likely have
the same output, but without all the 'snail-trails'.

They keep my backup system charged, and during the day I can run my
300-400 watt PC load, while in the float mode. They meet my needs.
Maybe next summer I'll do some more tests to see how they are holding up.

Sun Dandan · 11-21-11, 02:30 AM

Hi,
Thank you for your information.
Based on what I know. Those modules are not newly manufactured. Probably have been 'stayed' in warehouse for months...
Those stains probably occur due to rapidly ageing of the solar module. However, the reason causes this is still a question mark.
If you find any abnormalities of those stains like 'growing', change in colour/shape and such, pls post some photos here.
I will update you on this again.
Thanks ya~^-^...

Dan2

Xringer · 11-21-11, 10:27 AM

Well Dan2, you got me worried and I went out and looked.. Seems like more now.
So, I took some pics and compared them to old pics..
Yeah, it's growing. I checked 5 different pics of the area with the 'New' growth.
It wasn't there June 2010. And, most of the old 'marks' are getting bigger and darker.

Sun Dandan · 11-22-11, 12:00 AM

Hi,
em.... seems that the 'snail-trails' are spreading. Probably there are micro-cracks or physical cracks(not visible to human naked eyes) on the cells. So Oxygen penetrates into the cell and the conductors on solar cells start to oxidise due to Photobleaching phenomenon. This is just purely theory. We cant prove that yet. We still working on this.

How about the weather/climate condition? Any serious thunderstorms? snow storms or else during june 2010 to Nov 2011?

Xringer · 11-22-11, 08:19 AM

If these cracks exist, where would they be located? In the top or bottom surface?
I can inspect the glass with a 10x magnifier. But I doubt that I'll see defects, like tiny cracks.

My guess is chemical contaminates got under the glass during manufacturing.
It worked to deteriorate the cells and the conductors immediately after production.
And, the process of deterioration is still going on.
Perhaps with the sun acting to speed up the process, like a catalyst.?.

This is New England and we have had normal weather for this area.
See weather history data here:
Climatological Data

danxro · 12-02-11, 06:53 AM

Hello
My name is Daniel and I'm from Europe Romania
Mr. Xringer Got a request for you if you can help me with two pictures of the solar tracking circuit
one front and one back circuit
please help me
If you do not mind
I try to build a solar tracker circuit I
the pictures help me
build one
Thanks look forward to your response

marmar · 12-07-11, 03:20 AM

Dear Sun DanDan,

I am looking for information concerning the snail trails for an article for my journalism class.

I read on the forum that you are a researcher working on this topic so I thought you might help me!

So here are a few questions, I hope that this does not bother you...

1)the snail trails appear always after the panel has been functioning for some time? On average how much time? Can snail trails appear also later in the lifetime of a panel?

2)Do snail trails affect the performance of the module?

3)What are the possible hypotesis concerning the origin of such 'defects'?

4)Is it possible to enhance the formation and development of snail trails with ageing experiments? If yes what are the conditions that favour the most the formation of snail trails?

5)How can the formation of snail trails be avoided?

5)Is the grid finger conductivity and geometry affected by snail trails?

6)You mentioned that the origin of such trails might be related to micro-cracks in the cell, however often the path of those trails seems to 'continue' from one cell to the next, how is it possible?

Thank you very much

mm

OffGridKindaGuy · 12-09-11, 05:11 AM

Maybe it's a reaction between the type of glass and the silicone cells. They sure have a lot in common..

Just a thought..

PVSystem · 12-20-11, 12:19 PM

So, I took some pics and compared them to old pics..
Yeah, it's growing. I checked 5 different pics of the area with the 'New' growth.
It wasn't there June 2010. And, most of the old 'marks' are getting bigger and darker.

Goodevening Xringer, this is quite strange.. in our experience the snail phenomenon should stabilize itself after apperaing.. no further increase in the phenomenon should be applicable..

11-20-11, 08:18 PM	#12
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	I got them brand new. They were shipped from the importer Solar Panels -Buy Solar Panels from SOLARTECH POWER Complete Solar Panels Solution The marks were seen when they were unpacked (the first day). The back side of the panels seem to be perfect. There are more pics here.. Solar pictures by Xringer - Photobucket These panels have never really been good performers. Under idea conditions, they might put out 100w (instead of their rated 125w). My 200w Canadian Solar CS6P-200 panels (also made in China) work much better. With a well matched load, they will always put out 200w under most sun and temperature conditions. The importer offered to replace the 125w panels, but I didn't want to ship them 3,000 miles and hope to get back four new panels that would likely have the same output, but without all the 'snail-trails'. They keep my backup system charged, and during the day I can run my 300-400 watt PC load, while in the float mode. They meet my needs. Maybe next summer I'll do some more tests to see how they are holding up. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

11-21-11, 10:27 AM	#14
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Well Dan2, you got me worried and I went out and looked.. Seems like more now. So, I took some pics and compared them to old pics.. Yeah, it's growing. I checked 5 different pics of the area with the 'New' growth. It wasn't there June 2010. And, most of the old 'marks' are getting bigger and darker. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

11-22-11, 08:19 AM	#16
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	If these cracks exist, where would they be located? In the top or bottom surface? I can inspect the glass with a 10x magnifier. But I doubt that I'll see defects, like tiny cracks. My guess is chemical contaminates got under the glass during manufacturing. It worked to deteriorate the cells and the conductors immediately after production. And, the process of deterioration is still going on. Perhaps with the sun acting to speed up the process, like a catalyst.?. This is New England and we have had normal weather for this area. See weather history data here: Climatological Data __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

12-09-11, 05:11 AM	#19
OffGridKindaGuy Hi-Tech Hillbilly Join Date: Mar 2010 Location: Ohio Posts: 97 Thanks: 1 Thanked 16 Times in 15 Posts	Maybe it's a reaction between the type of glass and the silicone cells. They sure have a lot in common.. Just a thought.. __________________ If it don't, I'll always think it shoulda..

11-20-11, 06:58 PM	#11
Sun Dandan Lurking Renovator Join Date: Nov 2011 Location: Singapore Posts: 3 Thanks: 0 Thanked 0 Times in 0 Posts	Hi, I'm a student from Singapore. We have seen something like this before. And we are actually studying on this. We call it 'crack-shadow' or 'snail-trail'. The root causes of these stains/contamination/marks are not yet found. Could you tell me everything about your PV system? --> When did you buy those modules? Are those modules first-hand? What brand are those? When did you first see those stains and when is the last inspection? --> Weather/climate conditions. Any storm? High-Low temp? Humidity and such. --> Is there notable power drop? If yes, how much is the power drop. --> Have you done any test for those modules? Is there any hotspot when those panels operate? And could you take some pictures of the back of your PV panels? Any wrinkle on the backsheet of your pannels?

11-21-11, 02:30 AM	#13
Sun Dandan Lurking Renovator Join Date: Nov 2011 Location: Singapore Posts: 3 Thanks: 0 Thanked 0 Times in 0 Posts	Hi, Thank you for your information. Based on what I know. Those modules are not newly manufactured. Probably have been 'stayed' in warehouse for months... Those stains probably occur due to rapidly ageing of the solar module. However, the reason causes this is still a question mark. If you find any abnormalities of those stains like 'growing', change in colour/shape and such, pls post some photos here. I will update you on this again. Thanks ya~^-^... Dan2

11-22-11, 12:00 AM	#15
Sun Dandan Lurking Renovator Join Date: Nov 2011 Location: Singapore Posts: 3 Thanks: 0 Thanked 0 Times in 0 Posts	Hi, em.... seems that the 'snail-trails' are spreading. Probably there are micro-cracks or physical cracks(not visible to human naked eyes) on the cells. So Oxygen penetrates into the cell and the conductors on solar cells start to oxidise due to Photobleaching phenomenon. This is just purely theory. We cant prove that yet. We still working on this. How about the weather/climate condition? Any serious thunderstorms? snow storms or else during june 2010 to Nov 2011?

12-02-11, 06:53 AM	#17
danxro Dan_LASER Join Date: Dec 2011 Location: Romania Posts: 17 Thanks: 0 Thanked 0 Times in 0 Posts	Hello My name is Daniel and I'm from Europe Romania Mr. Xringer Got a request for you if you can help me with two pictures of the solar tracking circuit one front and one back circuit please help me If you do not mind I try to build a solar tracker circuit I the pictures help me build one Thanks look forward to your response

12-07-11, 03:20 AM	#18
marmar Lurking Renovator Join Date: Dec 2011 Location: italy Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts	Dear Sun DanDan, I am looking for information concerning the snail trails for an article for my journalism class. I read on the forum that you are a researcher working on this topic so I thought you might help me! So here are a few questions, I hope that this does not bother you... 1)the snail trails appear always after the panel has been functioning for some time? On average how much time? Can snail trails appear also later in the lifetime of a panel? 2)Do snail trails affect the performance of the module? 3)What are the possible hypotesis concerning the origin of such 'defects'? 4)Is it possible to enhance the formation and development of snail trails with ageing experiments? If yes what are the conditions that favour the most the formation of snail trails? 5)How can the formation of snail trails be avoided? 5)Is the grid finger conductivity and geometry affected by snail trails? 6)You mentioned that the origin of such trails might be related to micro-cracks in the cell, however often the path of those trails seems to 'continue' from one cell to the next, how is it possible? Thank you very much mm

12-20-11, 12:19 PM	#20
PVSystem Lurking Renovator Join Date: Dec 2011 Location: italy Posts: 3 Thanks: 0 Thanked 0 Times in 0 Posts	So, I took some pics and compared them to old pics.. Yeah, it's growing. I checked 5 different pics of the area with the 'New' growth. It wasn't there June 2010. And, most of the old 'marks' are getting bigger and darker. Goodevening Xringer, this is quite strange.. in our experience the snail phenomenon should stabilize itself after apperaing.. no further increase in the phenomenon should be applicable..