Cheap methods of encapsulating?

[PaulOtt]

Hello,

This thread convinced me that it could be good to encapsulate my solar cells to prevent corrosion. I have a piece of glass to which I am directly attaching my solar cells with about 1/8"space between the glass and cell. I'm using silicone caulk to seal the front of the cells while attaching them to the glass, and fill in between the cells.

I tried to also use that same caulk to completely cover the backs of the cells, but it doesn't spread very good and it does tend to shrink just a tad (it's noticable when spread then).

DesertFox25 has pointed out Sylgard which sounds great if I were doing three or more solar panels, but unfortunately I'm not.

As I understand it, I need something that is: (a) waterproof, and (b) semi-flexible so it doesn't prevent the expanding and contracting of the cells during naturally occurring temperature changes.

Here's the idea: I extend the seal of the caulk by putting down another layer of caulk on the edges of the cells creating a border around the back of the cell. Then before it cures I could pour in a solution, hopefully with the silicone caulk adhering to it and holding it in place. What about latex? Or an epoxy resin? Or what about laying down lots of layers of shrink wrap, then applying a heat gun or hair dryer? Maybe a premium paint, or latex-based finish?

Love the forums, have learned a lot already and looking forward to replies!

- Paul

[Mike90250]

At first glance, and from what I know about materials ability to allow moisture thru it (not water drops, but only molecules). Shrink wrap, most epoxys, and latex paints, will only slow it down, they won't stop moisture, from accumulating over several years.

Additionally, you need to have a method to remove heat from that nice dark blue PV cell, as the cell gets hotter, it's voltage output drops. In a 70V array, this can be up to a 8v shift. Commercial panels use the cells pressed against the cover glass, to disperse heat. An air gap will retain it, like a little solar oven. Measure a panel voltage, cold in the AM, and then again at noon. See the difference heat causes.

[Jason]

Check out this thread I just made Paul:

http://www.solarpaneltalk.com/showthread.php?t=1435

The NREL did a study with different materials for encapsulation and have them graphed.

[PaulOtt]

Additionally, you need to have a method to remove heat from that nice dark blue PV cell, as the cell gets hotter, it's voltage output drops. In a 70V array, this can be up to a 8v shift. Commercial panels use the cells pressed against the cover glass, to disperse heat. An air gap will retain it, like a little solar oven.

Doh. The reason I was leaving a gap is because I didn't want the shock transferred to the cells if something hit the glass, like a stick or hail or something like that. Do you not think that would be a problem if I pressed the cells directly to the glass?

Check out this thread I just made Paul:

http://www.solarpaneltalk.com/showthread.php?t=1435

The NREL did a study with different materials for encapsulation and have them graphed.

Double doh. Guess I'm going to try and buy some cheap desiccant and put it everywhere...


Oh and thanks for the replies guys, I really appreciate it.

[ecusolar]

I'm sure that we are short before a huge price revolution in solar panels.

Look at these prices.http://sunelec.com/index.php?main_pa...roducts_id=543

You will not be able to compite with DIY.

What we can do at the moment is to have a bridge untill prices will drop like a stone.

That's the reason why I say that I don't care too much how many years my DIY panles will last.

[kermitas]

I'm sure that we are short before a huge price revolution in solar panels.

Look at these prices.http://sunelec.com/index.php?main_pa...roducts_id=543

You will not be able to compite with DIY.

What we can do at the moment is to have a bridge untill prices will drop like a stone.

That's the reason why I say that I don't care too much how many years my DIY panles will last.

If you will ask me I will answer to not to wait.

For a years I read about cheap methods of producing cells or whole panels. For a years I read about efficiency 20%, 30% and even 40%.

I read about it and nothing happens !!

Who will drop down price if it already know how high they are ? If he/she start price war it will take years to drop down price because they will do it as slow as it can be (for example $1 every month).
Remember that every distributor, reseller and online store have to earn...and what would be better to earn than green energy ?

I'm feeling that they already can produce cheap cells (cheap for me means less $1 for 1W) - because I read about it few years ago.

People have to take care by their self, take problems in own hands. That is only one solution in this (photovoltaic) subject. You DIY panels will work for us next 5-10, maybe 20 years.

[ecusolar]

I would call 0.90USD/Watt a revolution and that will go further in the next years.

58 USD for a 60 Watt panel is reachable to almost anyone who has an own middle class house, it's only a bottle of whisky.

I hope my panels give me 6 years and maybe an additional bonus of 80% efficience for 3 years more, I would be very happy about that result.

the pictures of your 6x6 panels look good, do you have a pic of the finished panel?

If you will ask me I will answer to not to wait.


For a years I read about cheap methods of producing cells or whole panels. For a years I read about efficiency 20%, 30% and even 40%.

I read about it and nothing happens !!

Who will drop down price if it already know how high they are ? If he/she start price war it will take years to drop down price because they will do it as slow as it can be (for example $1 every month).
Remember that every distributor, reseller and online store have to earn...and what would be better to earn than green energy ?

I'm feeling that they already can produce cheap cells (cheap for me means less $1 for 1W) - because I read about it few years ago.

People have to take care by their self, take problems in own hands. That is only one solution in this (photovoltaic) subject. You DIY panels will work for us next 5-10, maybe 20 years.

[aaclevy]

solar panels

Its about the corporate life - solar panels are under $1 a watt - the $58/60 watt panel is here.

www.sunelec.com got 2000 panels in at $58/60 watts per panel...

You can buy 1500 watts to start - and the government pays you back in credits - so much so that here, in NC we get a total of 65% tax credit; reduced proportionally by the federal tax on the income from the NC tax credit.

Still, I calculate a a costs payback in only 6-7 years if I use 1.5" x 1/8th wall aluminum square tubing, bolts and the S-5! clamps. I can use a screwgun and have a metal roof... I might order another 25 panels too; i use avg 1000kw/mo but you can get a 30% discount on buying the new fujitsu halycom line - 26 seer on the 9000 btu one - and its a one ton heatpump too -- only $1600 bucks at younits.com... i've already bulb'ed the house with the CFLs.

Anyway, yeah... like 2000 for 1500 watts of panels and lke 800 in shipping. or a good reason to take a trip to miami.


SO that took a while.

Main Point!!! - the government pays 65% for it in NC, and if you're low income, you can take the credit over 5 years.
You can build and install a 1500 watt grid tie system for a very low price; for example i'm looking at the Tripp Lite APS2448UL 2400W 48V DC to AC Inverter

its only like $700... so $4500 in total components, with mounting tubes and then get code inspected...

You might want to put in safety devices.... lightning arrestors, fuses etc as required by local safety code.

[netttech]

I am tinkering with my panel tomorrow in regards to heat. My cells are actually semi-floating in the panel. The top cell of each column is glued (silicone) to a 2" strip of plexiglass which suspends the entire column of cells 1/16th off the backing.

I did that design in case I need to remove/work-on/repair a cell, I wouldn't destroy the entire string. After reading about the heat on the cells....I decided to add ventilation holes in the frame-work.

With the cells floating/suspended & ventilation holes added, it may provide cooling, up the voltage. If it works, I may re-design the panel to try capturing/transfer the heated air into the house....a combined collector.

I will post the results on the test.

[greenHouse]

i use avg 1000kw/mo

You need to get that WAY down. I haven't a clue what I use, but I get close to a $0.00 bill in Spring and Fall (the fees wind up being more than 25% of the bill, that's how low it gets) and I have a 2800 watt array and that's only about 350KWh / month for those months. Even in the Texas Summer, when I run the A/C all the time, my bills are about $75 for the electricity part -- that's 500KWh or so, plus the 400KWh I make.

So ... with A/C, a house full of computers, electric motorcycle (3.5KWh per charge, 2 or 3 charges a week), HD TVes times 3, etc. I use less than you average.

REMEMBER -- The cheapest watt is the one you never use.

[bladerunner]

I wonder about something here might work?

http://www.alumilite.com/Category.cfm?Category=Silicone%20Rubber

a side note, have been talking to a guy that has been researching this very subject for quite awhile. he says that silicone that you get in the store uses corrosive (to the solar cells) curing chemicals that will degrade your cells over time. One of the reasons that sylgard works great is because it uses alcohol (i think) for it's curing which does not degrade the cells.
He has bought a vacuum laminator and is planning on making panels himself, but highly recommends sylgard. He thinks manufacturing plants don't want to use sylgard because it does not lend itself to production (too labor intensive) although he thinks there is a manufacturer in SC that is considering making a line to do it. There seems to be some concern about the eva sheets breaking down before the 25 yr mark. Also, he says that tedlar is very necessary for minimizing UV breakdown of the eva sheet (for anyone who is considering going that route) I was, but am going to order some sylgard instead.

[DeltaFox 25]

You forgot one thing what ever you put on the fronf of the cells it has to be optical clear. I use sylgard all the time and it seam to be real good stuff.
.

[bladerunner]

True, it needs to be clear for the front, I was thinking of sealing the edges and using it more as a back encapsulating thing, problem with that seems to be the little bit of air in the front will probably corrode the faces of the cells as well.
I agree, for right now sylgard seems to be the only viable option, still wanting something cheaper though sylgard 182 looks like the best alternative to me still optically clear and all, just longer pot life, but at 36.85 per .5 kg,( at essex http://css.superioressex.com/scripts...temdetail.html) it's a little cheaper than 184 also if faster curing is wanted, it says you can heat it.
BTW, I am planning on ordering some, if I have to order 7, anyone want some?I would be willing to sell at my cost plus postage if so. let me know.
FIWIW, in looking at silicone, it seems two processes are used, one is tin catalyzed, one is platinum catalyzed. I bet this is the reason for such a huge difference in cost.

[DeltaFox 25]

The sylgard 182 you have to heat treat it to cure it. The sylgard 184 will cure itself. Loo at me last thread here and click on the diagram and really look at it. Buying sylgard at $36.85 is alokm cheeper then E-Bay. What's your price ( at Cost ) you would crarge for the sylgard.

[kermitas]

The sylgard 182 you have to heat treat it to cure it. The sylgard 184 will cure itself. Loo at me last thread here and click on the diagram and really look at it. Buying sylgard at $36.85 is alokm cheeper then E-Bay. What's your price ( at Cost ) you would crarge for the sylgard.

DeltaFox, Mike90250, are you one of them who used glass and solid polycarbonate on front in your panels ?? How solid polycarbonate works ??
It is not so clear as glass but can you see/fell the difference on output power ??
And what about cooling ? It is also not so good as glass. What did you used as backing ? Does heat is enemy of non-glass panels ??

@bladerunner - I am thinking to buy Sylgard, what would be your final cost that you can offer to me ?

Thanks,
Arthur.