my first attempt at home made panel

[martinjsto]

Hi all, I am new here and have read a lot of posts on home made panels. I understand the comments that your better off buying them and do not doupt the merits of that but i also believe from experience that you can make something as thats as good as a manafacturer with the right research and help but at half the cost (we will see with solar panels). you see im a make your own sought of guy having made my own wind gennerator, wind charger controler, picax logger and electric fence energizer.
i thought i would start my own thread about my first attempt at making a solar panel.
I have been researching the methods and have decided on 6mm laminated glass as i can get it for $2 per sheet that measures 60inch x 28 inch, silgard encapsulated, aluminium framed with bypass diodes as i have a bad shade issue.

I have seen a good way of encapsulating using cappilary action to help attain a bubble free encapsulation.
see:-

http://www.ases.org/papers/103.pdf

I am still working on the best diodes and circuit for the panel with the kind help of
rifraf.

http://www.solarpaneltalk.com/showthread.php?2188-Diodes-and-bypass-diodes/page1

I recieved my cells today from a full kit i purchased on ebay, unfortunatly they forgot to include the buss wire (another 2 week delay)
I purchased 108 6x6 cells 0.5 to 0.6v @ 8 amps for 3 36 cell panels, my multimetre is showing 0.59v in full sun so im estimating 4w each x 36 = 140w panel. I am taking pics and will post some soon.
any comments will be appreciated.
thanks all
martin,

SAM_0561.jpgSAM_0562.jpg

[martinjsto]

finnished the strings today, can be frustrating putting them together with them being so brittle, lost a few cells but progress is progress, found i had missed a few cells when testing and of cource they were located in the cetre of the strings anyway there good now and reading 4.5 to 4.9 volts per string , need to get them encapsulated ASAP or risk further breakage.
I have decided on a basic 36 cell panel with the two diodes as bypass.
just waiting for the missing buss wire now to finnish the soldering.
i have some other order with buss wire ariving early in the week so should be able to finnish wiring and encapsulate by wednesday all going well.
I still wouldnt mind some advice on wiring with 3 bypass diodes to protect 12 cells each if someone wouldnt mind.
a few more pics of the progress.

[RifRaf]

looking good, yes they are one of the most fragile things you have to work with and keep everything good on a large scale. and yes it sure feels good once they are encapsulated and the air pockets are out, but don't stand the panel up for several days after, let it cure

in the configuration you have, 4 strings of 9 or so, using 2 bypass diodes is the easiest way, if you had 6 strings then 3 diodes is easy. previously you had the cells arranged sideways in many strings of 2, 3 diodes would have been easier in that arrangement, but you would have used far too much bus wire hooking it all up that way so what you have done now makes sense for several reasons

[martinjsto]

thanks RifRaf, yer i figured the K.I S.S principle applies especialy with things you want to last and are so fragile.
how does this look now, pics below
i have simplified the wiring conciderably but will end up with 18 cells each side protected from shadows with minimum loss and easy repair.
Im a bit concerned the cells all had curveture to them when i umpacked them, a lot did seem to flaten a bit during the soldering process but again have to be real carefull.
the link i posted on the cappilary encapsulation uses the glass last. they place the cells face up on a bed of paper and other backing soft material in a frame. they then pour the sylgard on top and let the paper soak up the encapsulant after a while they pour the remainder over the top of the cells and then place the glass on top, this presses the cells into the bedding material and as the cells were already coated with the encapsulant had minnimal air pockets, they manipulated what air there was towards the edge then weighed down the glass with large weights untill dry. panels did look realy good but there is the concern about the curved cells i have, with the weight they applied. they are embedding down into layers of material that will support them quite well though.
my other method is with vacuum and space bags or vacuum pump and drawring the resin through.
what do you think?
thanks

[Jason]

thanks for sharing martin!

[Henrythecat]

I read that paper about the peasants. I never thought of encapsulating like that. thanks for posting that.

My first panel is drying on the kitchen table right now. With large air pockets in it... I did it the usual way of placing the cells face down on the front cover and pouring the Sylgard over it. I'm not too impressed, but I learned a lot from this.

Did you do it the way they do it? How did it go?

[martinjsto]

Thanks for the support Jason,
Henrythecat I have not yet done that method, havnt made a panel yet so your one up on me
I have set up my pour using a shallow alluminium frame that is about 25mm wide with a return of about 8mm. pics attached.
I have some of that plastic carboard stuff they make signes out of as the main backing that fits snugly into the frame, I then covered this with plastic sheeting the masking tape type that you use to protect the edge when painting, it has the masking tape attached so i wrapped it around the frame sticking it underneath and pulling it completly over the frame in layers working around to make a complete seal. I then put layers of calico down as a streinghthening material but i cant see why fiberglass sheets wouldnt work as this is the back, just the cost and whats on hand. on top of the calico then i have the paper, quite thick grade and as white as you can get.
on to of this goes the cells face up fully wired with the final connections cut and syliconed through to the back. the idear is that as you pour the Sylgard over top of the cells, the cappilary action draws the Sylgard under the cells into the material , the plastic and frame keeps everything in place and when the back looks completly wet you pour the rest of the sylgard on top and place the glass down, but i think i will thin some sylgard with white spirits and pour this on the paper to wet it all befor placing the cells down.
the combined thicknesses when assembled should mean my glass finishes about half way above the edge of the frame ready for the final edging, c channel aluminium. thats the plan anyway
the weight they use is a concern though as i am using the 6 x 6 cells, i think if I ensure I have a firm but giving backing and aplied some weight slowly and only as requires then all should bed in nicely.
if not i will end up with a lot of broken cells.
I am hopping this system will result with no or very minimal bubbles and a strong quality panel.

[martinjsto]

Aluminium Frame and testing the glass

Hi,
I have had to move my setup out to my shed after a big cleanout as the missus has requested her dinning room back, hows her form.:becky:
whilst im waiting for the buss wire i though I would make up the alluminium frame ready for welding once the rods arrive. I also tested the cells under the glass im using to see the difference in volts from direct sunlight. the one test cell made 0.574v in direct sunlight about 3pm, under glass the volts dropped to 0.569v only 0.005v drop i thought that result was quite good. I am using 6mm laminated glass from bathrooms.
its been to windy to dare to take a string of cells outside... I did that the other day and a gust blew in and off went 9 tabbed cells
i learned about their tendency to take flight at the slightest whim that day.

a few pics of the shed and frames, still gotta move more stuff out and organise the space but I finaly have a powered workshop.
a test on the 9 cell string in the shed under a outdoor spotlight gave 4.74v so assuming simmilar results over 4 strings is 18.96v, should be a good panel.

[SpaceOddacy]

So I've done fiber glassing and such on boats and cars.
That stuff is opaque and yellow, obviously wouldn't make good epoxy for the cells. Where do you guys find this clear stuff?

[martinjsto]

i got mine off ebay, cheaper the more you buy. you want Sylgard 184 or opticlear or another one i cannot remember the name right now.
there are a few threads about alternative places to buy on this site.
fiberglass resin will yellow and is too hard as an encapsulant for solar cells, you dont get the flexability like Sylgard and as different materials contract and expand at different rates you nees a flexible encapsulant to allow for this else your cells will shatter.

[RifRaf]

hi martin, a shame you lost some in the wind, and a bigger shame that you have the strings soldered up and no bus wire, keeping cells perfect for so long must be so hard, i have tryed to make each panel by spending 2 evenings soldering tab wire and making strings, the next evening laying them all out on the glass and the next morning, normally a saturday doing the encapsulating which gives me the hours to do it carefully with good light to see and remove bubbles etc.

the article you posted to the various processes being used was interesting, and good to see you trying one or something similar, though after 3 successful panels am sticking to me current method. will help with the diodes and stuff if you still need it.

spaceoddicy, sylgard has been used for many years, only in the last few years has it become available far easier and there are several methods with which you can properly seal cells and wire from the elements properly. maybe you should do some research around the internet, ebay and dare i mention it youtube, rather than jump on the 'DIY is impossible' bandwagon. if you are the kind that cannot do anything for yourself and have heaps of money maybe this is not for you. but if you are prepared try for yourself, have some mechanical ability and fairly basic electronics knowledge then making a proper panel is far from impossible.

please save the diy is not legal, fires etc. rants. just trying to help, not to argue

[SpaceOddacy]

i got mine off ebay, cheaper the more you buy. you want Sylgard 184 or opticlear or another one i cannot remember the name right now.
there are a few threads about alternative places to buy on this site.
fiberglass resin will yellow and is too hard as an encapsulant for solar cells, you dont get the flexability like Sylgard and as different materials contract and expand at different rates you nees a flexible encapsulant to allow for this else your cells will shatter.

Ahhh I see thank you!

[russ]

@ RifRaf - Well put!

DIY is NOT impossible for someone with the necessary skills.

At a minimum, it is an interesting science project for anyone wanting to try it and at the maximum end someone can build their own off grid system of a few kW quite nicely.

The sites offering to cut you loose from the utility bill for a couple of afternoons work and 200 dollars are impossible and a dangerous scam. People that get suckered in to that are not the people that have the necessary skills (normally anyway).

Anyone wanting to try is encouraged to try a small panel for the first go - guaranteed you will come across things you never dreamed of and the second try will be a big improvement. Not to mention, a small panel will be a smaller loss if things go down the toilet.

In the US, due to lack of certification by UL or similar parties:
1) DIY panels should considered for off grid applications
2) DIY panels should not be be erected on a structure where you do not want to invalidate the homeowners insurance. Non-certified electrical equipment cannot legally be connected to a utilities system.

Everyone gets away with things from time to time and certainly people have non certified items connected. The problem only comes if there is an incident and the insurance company or utility is looking for a reason not to pay.

Anyone that routinely works with electric installations is well aware of the electric code requirements. For those not in that line of work there is much to learn.

A fire, most likely, is started by improper connections somewhere in the system. To anyone that works with electricity routinely, proper connections are second nature but to the novice this is not so apparent.

Have fun at DIY - interesting projects! Please be aware of the potential problems while doing so and nothing should go wrong. Worry about the problems before they come up - not afterward.

Typically solar thermal (water or air) require a different set of skills than solar PV - more mechanical and less electrical. In many ways they are more in line with the capabilities of many of the DIY types.

Russ

[martinjsto]

The bus wire arived from the other suplyer today so I got busy, cut and soldered all the buss wires and the link to the junction box at rear, made up a glass lifting jig so I could place the glass exactly as required. checked the final output, 15.9v under indoor lights, good. then proceeded to prep everything for the pour. took my time and double checked all joints and when completly happy, mixed the Sylgard. decided to just do it in one go and then used a paint brush to evenly cover the cells.
then came the glass, remember i am doing this in reverse. the GPS holster glass clamps held well and i was able to millimeter by millimeter lower the glass down to the wet cells. as I was supporting the glass at the edges it naturaly had a droop towards the centre so as it contacted the cells the glass touched at the middle first, i waited untill it looked void of air and continued lowering a few millimitres at a time with long pauses in between. finaly the glass layed flat in position and the silgard was flowing well, i carressed a few air bubbles and added lots of weight. after a hour or two I had most of the air out and will leave it to the cappilary action to do the rest. all in all looks realy good, I expect to get some air bubbles but i did paint the cells completly with sylgard before the glass so the cells will still be sealed. I will check it regulary, if there is a problem i could always flip it over and put it in the vacuum bags before it drys.
a few pics to follow.
all going well I will leave now for a week then the unveiling.

[martinjsto]

more pics of the process