Epoxy for encapsulating cells (great DIY thread with photos!)

[Sandman57]

don't use epoxy

There are two issues with epoxy.

1. it is not flexable so any heating or contracting differences between the cells and epoxy will create strain on the cells.

2. Most epoxy is not UV resistant. In fact one year out in the sun and it will turn white or yellow and become brittle.

I wouldn't use it for encapsulation

[Jockito]

I have don that but with sylgard. I'm going to start a new way, First put sylgard on to the glass , then put the cells ( already tyed togeather and bussrar also) on top of the sylgard , then put more sylgard ontop of the cells. this way it will completly take any air out.

From what i inderstand of Sylgard, by pouring it over the cells it seeps underneath and all around cell, completely encapsulating it, this is what i saw done on a youtube video. Wouldnt that mean it is unnecessary to put Sylgard down first? The only thing to be mindful of that can happen is that air bubbles can get trapped if you dont pour it onto the cells right, but they can be "chased" out by moving or tapping the cells.

[DeltaFox 25]

I have made 4 panels the way the youtube guy made his and I have allways ended up with air pockets in it so now I;m going to put sylgard down first then cells then sylgard again.

[Jockito]

Oh ok. Thats interesting to know. I was thinking of doing it exactly how he was, but maybe i should think about it. It sounds like it would be difficult to handle the cells once all connected though if putting them down after the sylgard. for example, the solar panel im making is a 72 cell (4 columns x 18 rows), and soldering the bus wires together while the sylgard is wet sounds too tricky, which means i'd need to somehow hold the entire array of cells and place it on the sylgard...which i can't see how it would work.

I remember the youtube guy poured the sylgard so that only 3 edges of each cell had sylgard poured on it, allowing the sylgard to seep under without creating bubbles, but i guess if you tried it four times and it didnt work...

Also, do you think 2 Sylgards will be sufficient for a 72 cell panel? Im thinking of getting them off ebay, unless that superioressex website can send international? im from australia.

[DeltaFox 25]

Why don't you get another piece of plywood and assemble them ontop of that just like you were going to put them on the glass and then all you have to do when you put the sylgard down on the glass is to slide the cell's off the plywood on to the glass where you want them. You might have to have someone help you but it will be a better panel. Two slygards should be enougth but with that large of an panel it might be better to use more.
I'm doing a 72 cell panel of 5x5's 32x62 and I'm going to use 2 sylgard for the bottom and 2 sylgard's fro the top.
Where do you buy your sylgard at?

[Sandman57]

manual pour?

How do you guys handle a manual pour? My cells are not perfectly flat with a combination of slight concave and convex shapes. It seems that these curls would either trap air or require more encapsulent to cover them up.

I am lucky because I have access to a vacuum pump and autoclave. I have just ordered EVA sheets that I plan to use to encapsulate my cells in a vacuum bag. I will post some pictures to show the process.

[DeltaFox 25]

I'd really like to work with EVA and Tedlar but I just don't have the rood or the money to make a vacuum table.get another piece of plywood and assemble them ontop of that just like you were going to put them on the glass and then all you have to do when you put the sylgard down on the glass is to slide the cell's off the plywood on to the glass where you want them

[Jockito]

Where do you buy your sylgard at?

I haven't bought it before, but i was thinking from ebay. Do you know if Superioressex posts internationally? that way i could buy 3 for less.

[DeltaFox 25]

I think they want you to buy more , like 7 of them ,. I heard of a guy trying to buy from them and he was oversea's and they said that sence he was they wanted him to buy 7 of them. but if you can call them maybe they can help you. I buy 3 at a time.

[bladerunner]

Sylgard issues

Hello all,
I have been very busy making some panels for a friend in the Philippines, I used Sylgard to seal them because it seemed to be the most reliable method available.
I will post pictures eventually but wanted to share things I have learned that may help others avoid my mistakes.
I used 6X6 cells bought off e-bay that seem to work very well, just insanely fragile as most of you already know. One of the problems I have encountered is that when you are soldering the tab wire on the face of the cell, you MUST have a smooth finish to it, any bumps or spikes in the solder will hold the cell off the surface of the substrate (glass or acrylic or whatever) and cause a void or bubble. Also the bigger cells seem to warp as you solder them (I think this is due to heat being applied to one side of the cell) and I am not sure how to avoid that.
I first tried the method used on youtube with limited success, much of it probably my own fault (spikes in solder, curled edges, etc) too many voids.
I also read that you could speed the curing process by heating it. So I popped one in the oven, and it worked really fast (1/2 hr compared to 48+ hrs) DO NOT TRY THIS!!!!!! after I took them out, the cells buckled and cracked horribly! The voltage seems to be correct, but I have yet to try them for amperage output, am keeping fingers crossed. I am scared to try and flatten them back out, as long as they work I will probably leave them this way. Will post pics later, still busy making them.
The second method I have tried is to paint sylgard on the glass first, then put the cells on top, finishing with painting sylgard on the back, using weights to press the corners down into the sylgard seems to work well also (sockets, random bits of metal, lugnuts etc. I put bits of plastic under them to keep them from becoming glued down. A full sheet of plastic covering the whole back may be a better idea)
Gotta run for now, just wanted to share progress so far.

[DeltaFox 25]

I to have made a panel with the 6x6's but like you said they break very easy. I for some reason miss measured the glass and the frame so it left me with hardly any extra room. I have cell's overlapping the frame and no room in between. I guess I'll learn next time. I have decided to go with 5x5's . I can get them in grade "A" , so that will be what I'm going to use. I want to make several 72 cell panels.
It will be nice to see your pictures of what you have done.

[artificer]

DeltaFox 25:

Did you order your Sylgard from Superior Essex online or over the phone? I ordered online, and only ordered 2 units. $36.85 each, and $14.48 shipping for a total of $88.18.

I was looking for the Sylgard earlier, and found it at www.ellsworth.com. Their policy is $50 minimum order online, and $100 for service center (phone?) orders. Higher cost, but I only had to order one kit. Could be the same type of ordering policy with Superior Essex.

I picked up one of the Ebay auctions of (36) 6x6 cells. 3/16" tempered glass is available locally for $60.33 for 40"x40". All told, I should still be under $2/watt, and I don't have to spend a minimum of $500 or get a MPPT charger.

I plan on using a trowel with spacers to apply a thin film of the Sylgard, and then put down the cells. Cover with the remaining material. We'll see how it goes.

Michael

[DeltaFox 25]

I called Superior Essex to order my Sylgard but they told I had to get three of them . I did that because I knew I'd be using all of it sooner or later. I have decided to stick with 5X5 cell from now on and I'm going to make them 72 cell's . I already Have a Morningstar 60 amp MPPT Charge Controler and I have a 1000 watt inverter. I really need good batterys. I just have marine type batterys not solar.

[mrnewbie]

Michael a Trowel?
I don't think a trowel is gonna work..sylgard is almost like water..very thin..

I am on my 3rd large solar panel..6x6 cells 11 rows of 5..for 55 cells..around 27/28volts..these are LARGE panels 36" by 73". Haven't even hooked up yet..other than to test the 2 already completed with a voltmeter.

It takes at least a slygard and a half container to do a fair job of covering the cells. ESSEX BROWNELL still will ship sylgard..I have ordered them in quant 3..(someone mentiond they won't..but they did for me..twice)

The 6x6 cells are a real pain to work with they do curl..and break real easy..After I finish this last panel..I may switch to the 5x5 cells..

Ideas to consider...

6x6 cells....I use a hot glue gun..a hobbiest tool...I put a small drop on the corners/sides of the curling cells to hold them down..before sylgarding, it works real well! I too have 2 many air bubbles..gotta be a better way to do it

Someone somewhere mentioned they take little pieces of wax paper and put small weights on back on cells then add sylgard, then just leave the wax paper when sylgard dries..

I'm thinking about pooring the sylgard first..then putting my strings of cells on top of sylgard..in an attempt to get rid of the air bubbles..I can hook the stings together after sylgard dries, then seal it all up.

The sylgard seems to take 3 or 4 days to dry and remains sticky even then..

Covering back of panels...
I mentioned before using that rubber paint coating (earlier post)..I think this would work well and they do sell the stuff in White in a 1 gallon can..about 65$. I figure, it would do 3 or 4 panels easy. I have not tried it yet

Another option for rear cover..Home depot sells a cheap bathroom shower wall kit (or at least they used to..its been years)
This kit was simply several large sheets of a white plastic..panel like sheets
This could just be siliconed in there..just to add a backing.

[mrnewbie]

Thinkin ahead.....from another board...its me..

free glass????


"But, if I was to see a sliding glass door..or a storm door roadside with a big chunk of glass in it, I would be tempted to grab it. Could be an opportunity to save a few bucks" I can make my panels any size I want.

Thinking about the sliding glass door(2 large glass sheets-safety of some kind), where to find one?

I wondered what do the glass installation people do with the old glass doors, when they install a new one.
Do they recycle? Throw them away, I don't know.
So I'll find someone who does and ask.

Looked through the local phone book..found 4 or 5 places that install glass. Maybe I can get some used glass from one of em..thinkin a sliding glass door would be perfect.

The very first place I called..Told the guy I was trying to make some home made solar panels..
I could tell he found it interesting.
He told me to come on down, would find me something, What size do I need. Told him any large size and I was really looking to recycle and trying to find some big panels such as those in an old sliding glass doors. I then asked if they recycle those..He said nope, they just put em in the dumpster.
People like the term recycle..far preferred over the term..gimme for free.
Because I mentioned big panels, such as sliding glass doors..A light went off in his head. He said, you know I have a few sheets of tempered glass, I could let you have it real cheap. We ordered the wrong size, we can't cut it down its a tempered glass, we can't return it.
Its almost the same size as whats in a sliding glass door.

$20 bucks each..34"x74" almost perfect. 5 rows of 11 cells.
Not free but close


Moral of story...look for free glass

Note..real solar panels use a low iron special glass..real darn expensive.
I researched this glass a little bit and as I remember it lets about 97% of the light in..to cells

Regular glass..tempered/safety..lets in about 90 to 93%..a little less..but much more cost effective IF you can get it cheap..U worried about that 7%..just add a few more 2$ cells