EVA film -- EVA is a rubbery plastic that's very similar to hot glue.
This goes in between the PET film and the solettes, and when heated,
forms a perfectly clear, index-matched layer bonding the solettes to the
PET.Mechanically, it also cushions the delicate solettes and forms a
moisture barrier, waterproofing the panel. This is a pretty specialized
material, so you're unlikely to find a local source, but you can buy big rolls of it on ebay for pretty cheap.
Copper Tape -- this stuff is awesome. Shiny, real copper with an
adhesive backing! You'll use it to make electrical contact with the
enapsulated panel and make a nice connection that you can solder or
alligator-clip onto. You can pick it up at craft stores like Michaels,
or there are plenty of cheap sources on ebay.
Doublestick Tape -- you use this to hold the solar cells in place while
they're being laminated. The plastic gets all melty and skooshy, and
it tends to push the cells around unless they're taped down. The best
stuff is very thin, very strong tape. Get it at any stationary store.
Solettes -- This is where the solar magic happens. These are silicon
cells cut to whatever size you want. The size determines the current of
the solar cell--in this instructable, I'm using 52mm x 13mm cells,
which put out about 200mA Isc. You can get these from us or from ebay. If you do buy from ebay, be sure not to get cells with tabbing--you want just the bare solar cell.
A laminator -- Any desktop laminator will do. Use one you've got lying around, or pick one up from an office supply store.
A note for the true solar hounddog -- you can get particularly
beautiful laminations if you do a simple mod to your laminator to slow
it down, so if this project excites you, you might consider dedicating a
laminator to the pursuit of solar glory. I'll go into details of the
laminator mods in another instructable.
Step 3: An overview of the underbite

I'm
going to make this panel with what we call a "shingled solette"
technique. The solettes are held down to a PET backing using
double--stick tape, and they overlap one another slightly, so the
negative top of one solette is in electrical contact with the positive
bottom of the next solette, making a series connection that adds the
solettes' voltages.
What's wonderful about this technique is that
you don't have to solder anything. Just lay the solettes on top of one
another, laminate the solettes inside plastic, and the lamination holds
the solettes in solid electrical contact.
This video is a good
overview of the process--it's a sped-up video of me making a solar panel
from start to finish using this technique
Step 4: Step 1: It starts with a backing


The
first thing you'll need is a PET backing. I really recommend using
solar PET rather than the lamination sheets--it's a bit thicker and it
doesn't get as floppy when you melt it in the laminator. You can get
working panels either way (I used lamination sheets in the video), but
the panels come out cleaner with solar PET film.
Decide what
voltage panel you want to make. This will determine how many solettes
you have in your panel, and how long your panel will end up. If your
panel is voltage V, you'll have V/2 + 1 solettes, i.e. if you're making a
5V panel, that panel will have 11 solettes. The shingled solettes
should have about 1mm of overlap with their neighbors.
I'm
attaching a template for a 5.5V panel that uses 52x13mm solettes. This
makes a ~5.5V, 170mA panel that's good for charging 5V electronics, like
phones, cameras, and other devices. You can print the template
directly onto the rough side of the PET backing, which is quite handy.
If you use it, print it out at 1:1 scale on A4 paper.
If you
want to make a different size or voltage solar panel, that's fine.
Figure out how many solettes you're using and how large your backing
needs to be to accommodate them. You can as large a margin as you like
around your solettes.
Cut your backing out of PET and you're on your way!
Step 5: Step 2: Ze copper tape

The next thing to do is place the copper tape on your backing. This tape will bring out the electrical contacts from the panel and let you connect to the panel after it's laminated.
You'll notice the two sides of the PET have different textures--there's a smooth side and a rough side. The rough side is coated to make it stick better in a lamination. You're going to place the solettes on that side.

Cut two pieces of copper tape and stick them on either end of the PET.
Leave a bit of the tape hanging over the end of the PET piece, and wrap
that around to stick on the other side. Remember, everything on the
rough side of the PET is going to be laminated, so you won't be able to
get to it. Wrapping the tape around to the other side lets you access
the electrical contacts after the panel is laminated.
Step 6: Step 3--Doublestick


Whichever
piece of copper tape you place your first solette on will be the
positive contact of your panel. Choose with care, and you might want to
make a mark to remind yourself later (although you'll be able to look
at the solettes and figure it out, too)Place the solette so
it's centered on the PET and is overlapping the copper tape by several
millimeters. Be delicate with the solettes--they are quite fragile, and
it's easy to crack them. Press the solette down onto the doublestick
tape, and thar she goes.
One by one, add the rest of the solettes. Doublestick tape holds the solettes pretty permanently, so make sure you like how the solette looks before you press it down into the tape. If you do
misplacea solette, it's not the
end of the world.It'll probably
break, but try to twist it,rather
than peel it away from the tape.
It it does break, just pull the pieces
from the tape and put down a fresh
one.
When you get to the last solette,
take a moment to look at what
it's doing, electrically. The
bottom of the last solette contacts
both the previous solette and the copper tape.
t's a funny trick that we call the "false solette"
trick--we're just using the conductive bottom
of the solette like a wire to connect the top of the previous solette with the copper tape on the backing.
Once you've finished placing all your solettes, kick back in your chair
and take a deep breath. Relish this moment. One minute from now,
you'll be the proud owner of a finished solar panel, and everything will
change.
Step 8: Step 6--sudo make me a sandwich

Now is a good time to preheat your laminator
.
First up, make a lamination sandwich. Take a piece of EVA and lay it on top of the solettes, and then take another piece of PET and lay it, rough side-down, on top of the EVA. Your baby is ready for the hot rollers!
The doublestick tape should keep everything in place, but all the same, be gentle with the unlaminated panel. Pick it up and feed one end into the laminator. It's important to laminate the panel along the length of the panel--feeding it in a different way may crack your solettes. Chill Solar Dude made a drawing for you, for clarification.
The laminator will pick it up and start pulling it through. On the other side of the laminator, you'll see a beautiful panel emerge like a dhota from an air chrysalis.

You may notice that my laminator looks like the terminator
while he's being lowered down into the pool of molten steel. Yours doesn't have to look like that. I've been tinkering with my laminator so frequently that I've wised up and stopped putting the cover back on, but you just do this with a normal, off-the-shelf laminator, and it'll work just fine.
Most desktop laminators run too cold and fast to fully melt a panel. The easiest way to handle this is to pass your panel through the laminator several times, and each time, it'll melt a little more. This is a dirt-simple method, and it makes panels that work fine, but it leaves small bubbles inside a panel where the EVA didn't fully melt.

The best way I've found to make good-looking panels is to slow it down by stopping the laminator every ~10mm or so and waiting a few seconds for the panel to melt, then advancing it another 10mm. This lets the panel spend more time under the hot rollers, melting the plastic more thoroughly, and then the laminator's rollers can completely squeeze out any bubbles in the plastic, giving a perfectly clear, smooth panel.
When you're feeding the panel into the laminator, you might get your plastic layers slightly misaligned. That's fine. Once your panel is laminated, you can trim down any sloppy edges with scissors and get a nice clean edge.
Well there you go. Ain't nothing left to do but test 'er out
Step 9: Well? Did it work?
I made a nine-solette panel. One of those solettes
is a false solette and doesn't add voltage to the
panel, but each of the other solettes adds half a volt
at the max power point, so I should see 4 volts at
the max power point.
I plugged it into our little solar testbed, and lo and
behold, the panel's putting out 208mA at 3.7V at
the max power point, or .75W. Pretty good, ain't
that right, Chill Solar Dude?
Step 10: Wellsir, I reckon it's time to hit the ol' dusty trail
Well, that's about it I reckon. Go forth and build cool stuff. Show everybody what you make in the comments!
If you think this is neat, well, my amigo Shawn and I do this all the time, and we're busy making lovely tiny little machines that make solar panels