Which encapsulant is best

[Mike90250]

EVA is a hot melt glue, used between the Glass and the cell wafers. When heated it goes clear and flows.

TEDLAR is used as the white back sheet, it's adhered to the back side of the wafers somehow (maybe another sheet of EVA, I am not sure how the stack is made anymore)

The front side glass is a UV blocker, and the white tedlar is UV resistant and water vapor proof. The EVA will slow water vapor, but it is not absolute.

Fieldlines board has a great post/tutorial on how to do it right:
Oztules' series (at Fieldlines):

http://fieldlines.com/board/index.php/topic,144982.0.html

http://fieldlines.com/board/index.php/topic,144995.0.html

http://fieldlines.com/board/index.php/topic,145004.0.html

Learn from them.

[thehandyman]

I couldn't pick up cells that were already soldered together, they would break.

So the cells would just be lying directly on the glass; what is to keep a large column from
just sliding to the bottom when the panel is vertical? The EVA holds everything, but with
the (not connected) cells in between, how does it connect to the glass? Seems like there
would be very little contact. What sort of vacuum would be used, and what kind of heat
to seal the EVA? I envision the edges of the EVA being sucked under cells. Bruce Roe

Have you ever examined the back of a commercial solar panel?

The EVA adheres to the cells AND the glass. When the heat gun is applied to the back, it transforms from solid-flexible to near liquid. It will not go between the cells and the glass unless there is a thick solder joint preventing the cells from laying flat against the glass.

Properly done, as in the video I showed you, the EVA in its super heated state will melt (And is pulled in by vacuum, start heating furthest from the vacuum connection as possible. Work towards where the vacuum is connected so you do not accidentally clock the vacuum action. It will melt to the glass, too, isolating each individual solar cell, providing that you spaced them out enough, usually 1/8" is fine.

For example, I have a commercial Sharp panel @ 250 watts that has a bag cell, with a perforation penetrating the EVA. the cell is discolored, but it is separate from all the rest.

Just make sure you have the cells spaced far enough apart from each other. If your current cell column is too close, you can try it, but in the future, make sure they lay perfectly flat, and space them out using ceramic tile spacers from Lowes.

[bcroe]

Why not do what the solar panes manufacturers do?
Make sure the cells are cleaned with 99% iso alcohol in an ultrasonic cleaner... Solder them, place
them face down on glass, place a sheet of EVA (EVA is cheap) over the backs of the cells.

Since you are a home brewer, tape the edges of the EVA to the glass, except for one spot. Tape the end of a vacuum to the small open spot, turn the vacuum on. It will suck out all the air and achieve a uniform coverage. Using a heat gun, heat the EVA until it adheres to the glass, going on down.
After that all that is needed is to attach the borders, and run the wires into a hook up box.

I wouldn't trust any adhesives. I have two Carizo solar cells that are older, that have yellowed significantly from the glue they used back in the day. EVA is the way to go. And it's cheap. You'll find the most expensive part is the tempered glass. You cannot use standard glass, it will shatter and ruin your panel. You have your pick of borders, as long as it supports the glass and keeps it safe.
Here you go: https://www.youtube.com/watch?v=FAFMv-X9IkE

I couldn't pick up cells that were already soldered together, they would break.

So the cells would just be lying directly on the glass; what is to keep a large column from
just sliding to the bottom when the panel is vertical? The EVA holds everything, but with
the (not connected) cells in between, how does it connect to the glass? Seems like there
would be very little contact. What sort of vacuum would be used, and what kind of heat
to seal the EVA? I envision the edges of the EVA being sucked under cells. Bruce Roe

[thehandyman]

Why not do what the solar panes manufacturers do?

Make sure the cells are cleaned with 99% iso alcohol in an ultrasonic cleaner... Solder them, place them face down on glass, place a sheet of EVA (EVA is cheap) over the backs of the cells.

Since you are a home brewer, tape the edges of the EVA to the glass, except for one spot. Tape the end of a vacuum to the small open spot, turn the vacuum on. It will suck out all the air and achieve a uniform coverage. Using a heat gun, heat the EVA until it adheres to the glass, going on down.

After that all that is needed is to attach the borders, and run the wires into a hook up box.

I wouldn't trust any adhesives. I have two Carizo solar cells that are older, that have yellowed significantly from the glue they used back in the day. EVA is the way to go. And it's cheap. You'll find the most expensive part is the tempered glass. You cannot use standard glass, it will shatter and ruin your panel. You have your pick of borders, as long as it supports the glass and keeps it safe.

Here you go:

https://www.youtube.com/watch?v=FAFMv-X9IkE

[paara]

Prices for encapsulant on ebay including shipping:
-Sylgard 184: 359$ for 6,6 pound
- Qsil 216: 220$ for 6,6 pound
- Syl cell 1084: 188$ for 7,7 pound
- Cell gard: 288$ for 6,6 pond

Has anyone used Syl-cell? It is the cheapest, and if the aforementioned products are somewhat similar I am thinking of going for this.


Did some calculation to check approximately overall price which include shipping and VAT: 1$ per watt. (2kw cells, bypassdiods, tabbing/bussbar. I bought 2kw worth of solar cells so I could make another 1kw panels if the result is okay for a lot less. Glass and frame I have for free.) Labour will be for free since this is a hobby project, but would probably amount to 2-3x material cost if included. Thus my conclusion is as many times mention in this DIY forum section. DIY will not save money (in the long run), but that was never the point.

[bcroe]

Thanks you for your insight. Looks very good. Maybe i have to order a "panel vibrator". I had planed to keep the panels enclined when poring the capsulant like this video shows:

Cell-syl or qsil seems to be the cheapest products for encapsulation.

I am doing the diy panels as a project for fun/learning. Will probably buy solar panels later. For me here in Norway the "store bought" panels will cost around 2$ per watt. Online similar due to shipping cost and VAT. DIY panels around half that, but probably with much shorter time to failure.

I did some tilting of my panel, but not a lot or the encapsulant would run over my 1/4" high
plastic rails. I think the vibrator might be less labor intensive; maybe a combination is best.
Or build that vacuum chamber to urge the air out. I load tested cells before hand; I think
more practical & through than trying to test them after soldering & before encapsulation. A
voltmeter won't detect a low current (cracked) cell.

There are bus jumpers at the ends of every column; I found these laborsome to make to
close dimensions. The 1/4" wide tabbing was quickly bent over this jig to a height of 1/4"
(above the encapsulant), cut to the ink lines for the panel output. For jumping between
columns of cells, the bus length was made the total jig length. These were epoxied to the
glass in advance, just outside the cell area.

For most panels I bought aluminum and tempered glass from industrial sources; much cheaper
than retail. Then there's hardware, cells, encapsulant, other stuff. While my 1/4" square spacers
did keep things in place, they reduced the useful area of the panel. Here it just doesn't add up
financially. Bruce Roe

[SunEagle]

Getting a bit off track here. There are 40 panels NOT deployed, you can't count them.
Not a "classic" design: a NW IL design that generates KWH rain or shine.
Although a lot of mods have been made, the original installer has inspected everything
and found it to be completely compliant with all regs. The (grid connected) working panels
are nicely keeping the house toasty, with the aid of a heat pump. If this winter keeps
letting me run the heat pump, there might be a big KWH surplus.

Keeping the snow off hasn't made concrete progress. It should work to an absolute minimum
of manual intervention. Getting them vertical for snow season ought to help a lot, but
changing them manually twice a year is a BIG project. Maybe a mechanism to set them just
over vertical each snow fall could work well (and void the warrantee), but that means a
complete support redesign with built in activators; a long term project. With all snow
falling off the front (instead of pushed off sides & top), they might need to be higher off
the ground to clear accumulation. An alternative is near vertical all winter with ELECTRIC
defrosting as needed, also a very big project that likely voids the warrantee. Tests on my
DIY panel indicate it is doable. Maybe should set up a spare 250W and test the idea now!

There is another thought to put all the east facing panels at the west side of the clearing
to minimize shading; west facing located far east. All this could be done at one time,
some year. Bruce Roe

Back on topic.

Based on your "hands on" experience it is nice to let others know that there are proven ways to properly encapsulate the cells in a DIY panel which will produce a final working product. Although also providing some background that it will take more than a few trials to get a working product may help others think about what they are getting into.

As for the off topic, I like your idea of switching the E & W arrays to minimize shading issue.

[bcroe]

I agree that panel could be used for a vehicle battery tender. At
least it will be put to use after all those hours and trials to build it.

150 panels!!!. I never counted them from your pictures so I didn't realize how huge your system is.

I remember you were looking to modify your Southern facing array so they could be tilted
to reduce snow accumulations. Were you able to come up with a solution yet?

Getting a bit off track here. There are 40 panels NOT deployed, you can't count them.
Not a "classic" design: a NW IL design that generates KWH rain or shine.
Although a lot of mods have been made, the original installer has inspected everything
and found it to be completely compliant with all regs. The (grid connected) working panels
are nicely keeping the house toasty, with the aid of a heat pump. If this winter keeps
letting me run the heat pump, there might be a big KWH surplus.

Keeping the snow off hasn't made concrete progress. It should work to an absolute minimum
of manual intervention. Getting them vertical for snow season ought to help a lot, but
changing them manually twice a year is a BIG project. Maybe a mechanism to set them just
over vertical each snow fall could work well (and void the warrantee), but that means a
complete support redesign with built in activators; a long term project. With all snow
falling off the front (instead of pushed off sides & top), they might need to be higher off
the ground to clear accumulation. An alternative is near vertical all winter with ELECTRIC
defrosting as needed, also a very big project that likely voids the warrantee. Tests on my
DIY panel indicate it is doable. Maybe should set up a spare 250W and test the idea now!

There is another thought to put all the east facing panels at the west side of the clearing
to minimize shading; west facing located far east. All this could be done at one time,
some year. Bruce Roe

[paara]

With larger cells, its hard to get the bubbles out between them and the glass. I took
an old hand vibrator, attached it to a wood block, and bolted it to the panel frame.
The voltage was gradually turned up with a variable transformer, till the level of
vibration seemed OK. It worked, first time all the bubbles were gone.

There is 1/4" square plastic rod epoxied around the edge to guide cells and
contain the encapsulate, just visible. There are also 2" strips between columns
of cells about every 6", as guides. Once its done, a backing can by laid on the
plastic rod, used as spacers from the cells. Bruce Roe

Thanks you for your insight. Looks very good. Maybe i have to order a "panel vibrator". I had planed to keep the panels enclined when poring the capsulant like this video shows: https://www.google.no/url?sa=t&sourc...vSLDB2HXGLyjPg

Cell-syl or qsil seems to be the cheapest products for encapsulation.

I am doing the diy panels as a project for fun/learning. Will probably buy solar panels later. For me here in Norway the "store bought" panels will cost around 2$ per watt. Online similar due to shipping cost and VAT. DIY panels around half that, but probably with much shorter time to failure.

[SunEagle]

I made quite a few attempts back then, starting with what I saw on the internet.
They all failed in a very short time. As a result I came up with this scheme. This
last panel is a success, all good cells, and delivering the expected power. Guess
it needs to be on display somewhere with the other stuff. Maybe power my
stored vehicle battery maintainer, which can tolerate the intermittent PV power.
About a year old, has several times as much encapsulant as allegedly needed.

All those lessons taught me there was no way to come into the same ballpark
of practicality of commercial panels, at under $1 a watt. There are over 150
commercial panels here, 2/3 in daily service. Bruce Roe

I agree that panel could be used for a vehicle battery tender. At least it will be put to use after all those hours and trials to build it.

150 panels!!!. I never counted them from your pictures so I didn't realize how huge your system is.

I remember you were looking to modify your Southern facing array so they could be tilted to reduce snow accumulations. Were you able to come up with a solution yet?

[bcroe]

Bruce. Nice set up.

Is that panel providing you the expected VA output and how old is it?

I made quite a few attempts back then, starting with what I saw on the internet.
They all failed in a very short time. As a result I came up with this scheme. This
last panel is a success, all good cells, and delivering the expected power. Guess
it needs to be on display somewhere with the other stuff. Maybe power my
stored vehicle battery maintainer, which can tolerate the intermittent PV power.
About a year old, has several times as much encapsulant as allegedly needed.

All those lessons taught me there was no way to come into the same ballpark
of practicality of commercial panels, at under $1 a watt. There are over 150
commercial panels here, 2/3 in daily service. Bruce Roe

[SunEagle]

With larger cells, its hard to get the bubbles out between them and the glass. I took
an old hand vibrator, attached it to a wood block, and bolted it to the panel frame.
The voltage was gradually turned up with a variable transformer, till the level of
vibration seemed OK. It worked, first time all the bubbles were gone.

There is 1/4" square plastic rod epoxied around the edge to guide cells and
contain the encapsulate, just visible. There are also 2" strips between columns
of cells about every 6", as guides. Once its done, a backing can by laid on the
plastic rod, used as spacers from the cells. Bruce Roe

Bruce. Nice set up.

Is that panel providing you the expected VA output and how old is it?

[bcroe]

With larger cells, its hard to get the bubbles out between them and the glass. I took
an old hand vibrator, attached it to a wood block, and bolted it to the panel frame.
The voltage was gradually turned up with a variable transformer, till the level of
vibration seemed OK. It worked, first time all the bubbles were gone.

There is 1/4" square plastic rod epoxied around the edge to guide cells and
contain the encapsulate, just visible. There are also 2" strips between columns
of cells about every 6", as guides. Once its done, a backing can by laid on the
plastic rod, used as spacers from the cells. Bruce Roe

[FunGas]

I can't give you a comparison, but Sylgard 184 is pretty easy to use. OK it's not exactly cheap, but you only use it once and it's worth the outlay.
Takes about a week to cure fully.

I made a 1m² panel and my cells were not perfectly flat on the glass, one tub was just enough to do the job.

Put a bead of silicone around the area you want to encapsulate, it might only be an inch or so around the border, but it will give you a little bit more to play with...

[paara]

Does anyone have any recommendation for encapsulating solar cells? What is the best regarding price, durability and easy to work with?

Are there any significant differences between sylgard 184, qsil 216, syl-cell 1084, cell guard or eva-tedlar? Eva seems to be the hardest to work with?

Any recommendation or experiences you could could share.

Panels to be encapsulated: 60 6x6 cells, glass 173x95cm.

Greatful for any help.