Prep work for some DIY solar panels - Page 2

Xringer · 11-23-12, 10:07 PM

Wow, your UO SRML plot looks totally weird. In February, the top of my bald head would get sunburn!

I'm gonna guess about 70 degs. Or, 30 degs up (tilted north) from laying flat..

That should give you a good rain-wash angle and might be near the optima angle for best average year-round power harvest.

Or, use adjustable tilt and change the angle when power starts dropping off..

Wayan · 11-23-12, 10:46 PM

keep in mind that the sun actually passes overhead from a northern position, across to the southern!

here is a pic from the satelite tracker to better explain:

thats the sun north of us in June,

and the sun, south of us in DEC!

so placing the panel at 30% facing north (or in my case north west due to my roof) would mean that all the months that the sun is actually to the south, i would not be getting a good exposure.

so i think i would need to place it as flat as possible, right?

Mikesolar · 11-24-12, 06:37 AM

Proper backsheet should cost about $20 ea if you can get it from a manufacturer and EVA might be similar. I have been to a few manufacturing plants (there are a lot next door to you in Malaysia) and without the equipment it will be tough but do able. All I can say is "have fun"....

Xringer · 11-24-12, 07:38 AM

Two pictures are worth 2000 words (to this old man)..

Looking at the those pictures, I would guess the sun is in the northern sky,
for more days than it's in the southern sky.
So, if you were to add a few degrees of rain-drain tilt, the low end should be to the north..?.

Where I live, the snow just slides right off..

http://i46.photobucket.com/albums/f1...r/nearmiss.jpg
April 1, 2011

http://i46.photobucket.com/albums/f1.../ScrSav000.jpg

Wayan · 11-25-12, 01:55 AM

Quote:

Originally Posted by Mikesolar

Proper backsheet should cost about $20 ea if you can get it from a manufacturer and EVA might be similar. I have been to a few manufacturing plants (there are a lot next door to you in Malaysia) and without the equipment it will be tough but do able. All I can say is "have fun"....

what does the backsheet do? is it just an added layer of protection from the back? it looks a little like the plastic film that people use to make car stickers with, etc.

does the color of the backsheet affect the solar output? ive seen people stay with clear, some people do white, and others go black... but most manufactured panels seem to be white i think.

i think black would not be good because it would absorb additional heat into the panel, and solar cells tend to have a lower output the hotter they get. so i guess clear would allow IR to pass right through the small gaps between the cells, or white would help reflect the heat back out... any suggestions what might be best?

Mikesolar · 11-25-12, 11:10 AM

Most backsheets are white "Tedlar" from Dupont or an equivalent. Some panels come with black as an option. Tedlar is a laminated polyester film and is the best barrier to liquid getting on the electric components so it is VERY important for longevity. If you want clear, the best thing is two pieces of glass (glass-eva-cells-eva-glass). I believe that you would need to make a heated laminator if you wanted to do this really well.

Wayan · 11-25-12, 12:55 PM

wow, 2 layers of glass is gonna weigh a heaps! i think ill do:

glass (probably 4mm tempered) - EVA - the cells - Eva - and a layer of resin just for good measure...

i wanna come up with some way to encapsulate with the eva in a good way first tho, that ill be a challenge in on its own i think... gonna have to think out of the box a little...

to get a good result that is, im not thrilled about the heat gun trick that most people are showing on youtube. i wanna make an oven + vacuum

Mikesolar · 11-25-12, 06:21 PM

The standard low iron solar glass comes in 3.2 and 4mm with 3.2 being the most used. Low iron glass will allow about 90-91% of the light through and regular will be around 82% or so so if you are trying to maximize output, a few extra bucks for proper solar glass is worth it.

Wayan · 11-25-12, 09:18 PM

ive asked (but will check again at some different suppliers) the thinnest tempered crystal glass (low iron glass) that is available is 6mm, and it costs way way more than regular 4mm tempered glass. $45 compared to $17.5

i think i would rather put the extra $30 into another solar panel, since it would be more efficient than getting the crystal glass ($$ to watt ratio-wise).

IF i can find cheaper 4mm crystal glass for maybe around 20~25 bucks i would lean towards that... since in the end i would like to try and make the best possible panels that i am able to get (home made), since its something that should last as long as possible, and make as much power as possible during that lifetime.

11-23-12, 10:07 PM	#11
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Wow, your UO SRML plot looks totally weird. In February, the top of my bald head would get sunburn! I'm gonna guess about 70 degs. Or, 30 degs up (tilted north) from laying flat.. That should give you a good rain-wash angle and might be near the optima angle for best average year-round power harvest. Or, use adjustable tilt and change the angle when power starts dropping off.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

11-23-12, 10:46 PM	#12
Wayan Lurking Renovator Join Date: Nov 2012 Location: Bali Posts: 17 Thanks: 1 Thanked 0 Times in 0 Posts	keep in mind that the sun actually passes overhead from a northern position, across to the southern! here is a pic from the satelite tracker to better explain: thats the sun north of us in June, and the sun, south of us in DEC! so placing the panel at 30% facing north (or in my case north west due to my roof) would mean that all the months that the sun is actually to the south, i would not be getting a good exposure. so i think i would need to place it as flat as possible, right? Last edited by Wayan; 11-23-12 at 11:54 PM..

11-24-12, 07:38 AM	#14
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Two pictures are worth 2000 words (to this old man).. Looking at the those pictures, I would guess the sun is in the northern sky, for more days than it's in the southern sky. So, if you were to add a few degrees of rain-drain tilt, the low end should be to the north..?. Where I live, the snow just slides right off.. http://i46.photobucket.com/albums/f1...r/nearmiss.jpg April 1, 2011 http://i46.photobucket.com/albums/f1.../ScrSav000.jpg __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less.. Last edited by Xringer; 11-24-12 at 08:27 AM.. Reason: adding old tracker pic link..

11-24-12, 06:37 AM	#13
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	Proper backsheet should cost about $20 ea if you can get it from a manufacturer and EVA might be similar. I have been to a few manufacturing plants (there are a lot next door to you in Malaysia) and without the equipment it will be tough but do able. All I can say is "have fun"....

11-25-12, 11:10 AM	#16
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	Most backsheets are white "Tedlar" from Dupont or an equivalent. Some panels come with black as an option. Tedlar is a laminated polyester film and is the best barrier to liquid getting on the electric components so it is VERY important for longevity. If you want clear, the best thing is two pieces of glass (glass-eva-cells-eva-glass). I believe that you would need to make a heated laminator if you wanted to do this really well.

11-25-12, 12:55 PM	#17
Wayan Lurking Renovator Join Date: Nov 2012 Location: Bali Posts: 17 Thanks: 1 Thanked 0 Times in 0 Posts	wow, 2 layers of glass is gonna weigh a heaps! i think ill do: glass (probably 4mm tempered) - EVA - the cells - Eva - and a layer of resin just for good measure... i wanna come up with some way to encapsulate with the eva in a good way first tho, that ill be a challenge in on its own i think... gonna have to think out of the box a little... to get a good result that is, im not thrilled about the heat gun trick that most people are showing on youtube. i wanna make an oven + vacuum

11-25-12, 06:21 PM	#18
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	The standard low iron solar glass comes in 3.2 and 4mm with 3.2 being the most used. Low iron glass will allow about 90-91% of the light through and regular will be around 82% or so so if you are trying to maximize output, a few extra bucks for proper solar glass is worth it.

11-25-12, 09:18 PM	#19
Wayan Lurking Renovator Join Date: Nov 2012 Location: Bali Posts: 17 Thanks: 1 Thanked 0 Times in 0 Posts	ive asked (but will check again at some different suppliers) the thinnest tempered crystal glass (low iron glass) that is available is 6mm, and it costs way way more than regular 4mm tempered glass. $45 compared to $17.5 i think i would rather put the extra $30 into another solar panel, since it would be more efficient than getting the crystal glass ($$ to watt ratio-wise). IF i can find cheaper 4mm crystal glass for maybe around 20~25 bucks i would lean towards that... since in the end i would like to try and make the best possible panels that i am able to get (home made), since its something that should last as long as possible, and make as much power as possible during that lifetime.