Step-by-step DIY Solar Cell Soldering: Green Power Science
Posted by carrie_roll
Denise and Dan Rohas are truly an awesome pair and have done a great job with this video, as with the vast majority of videos they make.
So, we had the video transcribed and posted it here on GreenJoyment for you to have a text and video version of how solar cells work and how to soldier your own solar cells together (with a lot of patience and a fair amount of cash).
Enjoy!
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Other articles you may also enjoy:
http://www.greenjoyment.com/how-to-build-your-own-solar-panel-solar-cell-electricity.html
http://www.greenjoyment.com/wind_turbines_made_simple_how_to_build_your_own_electricity.html
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Hello there, I’m your host Dan Rohas …. and I’m Denise Rohas and today we’re going to make our own solar panels.
This is the famous Harbor Freight solar panels that we’ve used in many of our previous videos. Today, we’re going to be using cells of a different type.
There are three basic type of cells used in most solar panels. The least efficient and least expensive of these cells is the amorphous cell. (Amorphous solar comes in a film that is deposited on a substrate. This varies and include glass, plastic or metal.) Now this is what the Harbor Freight system is; the cells are deposited on glass usually and there are kits that come with this, they’re really tricky to work with. I pretty much don’t advise you to try to make these. The nice thing about these because they are deposited on glass, even though they are less efficient than the other types of cells, is the fact that you can just dunk these in water – you can pretty much do anything with them; they are really, really durable.
There are also mono-crystalline – those are hexagon cells. Those are the most efficient and the most expensive. The cell that we’re going to be working with today is poly-crystalline. These cells are about a watt and a half, almost two watts apiece (actual cell specifications: Watts: 1.70 Wp, Amps: 3.5 Imax and Volts: 0.5 Vmax) and you can get these in lots of 100 – you can get them in just about any size. These cells you have to tab them together. Now one thing about these cells is they’re very fragile! You can see that it didn’t take much for you to break that. You have to be really careful when you work with these because that was about a $2 break that I just did right there.
Now one thing about these cells is they are about one and a half to two watts apiece, but they’re .5 volts. So in order to get your voltage up to charge a battery – say to 18 volts or 20 volts — you need to chain together 36 of these or 40 of these, depending on what voltage you’re looking for.
So what we’re going to be doing is tabbing these cells together today.
There are basically three different things that you need for this. You need tabbing wire which is a thin wire that’s got a deposited metal (coated with tin) on it; this actually solders to the cells. There’s also a bus wire – it’s basically the same thing as tabbing wire but it’s a lot thicker so it handles more amperage and you use this to tie your strings of cells together.
There’s also some silver solder (tin, lead-free) which basically you use to enhance the soldering joints. You’re also going to need a soldering iron. Now, they usually recommend that you use a 65-watt iron; we’re going to use one a little bit less than that.
We’re going to show you the basics for this and in future videos we’re going to show you how to add a lot of components to the solar panels.
So we’re going to get started, I’m going to plug the soldering iron in. One thing that Dan forgot to mention is that he’s going to be using this flux pen. (Dan is going to show you all the steps though for how to solder solar cells.) Now this pen it actually smells like rubbing alcohol (do not smell pens!) and what it does is it opens up the cells so that way it can accept a better soldering joint.
When you get your cells, they usually come in a bundle like this and as I said, they are extremely fragile, this is another one that I broke. So you want to be very careful with these and handle them with care. I’m going to show you a close-up of these and explain exactly what’s going on with them.
What you’re going to notice with these cells is that there are a series of small white lines and two big lines; this is where your tabbing wire goes. Now on the backside, there are also six little joints where you solder the tabbing wire to. Most solar cells like that are usually negative on the front – positive on the back. So in theory, you could take a bunch of them and stack them together like batteries to build up the voltage. The problem is only one cell would get the sunlight so you can’t do that. So what you end up doing is you end up taking tabbing wire and you run it down the length of this and you leave some extra and the next one attaches to the back of the next cell and you go from there. So you end up tabbing them together like this in long chains.
We’re going to lay it flat like that. You take your flux pen and you basically just go right up and down it – now it’s a good idea to not drink a lot of coffee the day you do this, like I did, because the steadier your hands are — the better off you are. You want your tab wires to be twice the length of the cell; now I went ahead and cut these in advance. You basically just measure it and double it over. It’s a good idea to do all of your tabbing wires in advance – that way you don’t have to come back and do this step.
Also, be careful with your soldering iron; I just grabbed it in the wrong spot and burned my fingers so I’m going to have two nice blisters. But you basically try to get it started so you know where you’re going to end and you hold it down and the tin that’s on the outside of this should adhere to this and you can see that that locked down. Now you’re going to hold it the length just like I have it, you take your soldering iron and you hold it flat like this and you just gradually work it down the length of the cell.
Now that you have two of these tabbed, you’re going to take them and flip them over and you’re going to attach them like this. You’re going to want to get this tabbing wire nice and flat — get it nice and straight; and you’re going to arrange them like this. Now it’s a good idea to have a setup of exactly what you’re doing. Some people will build little forms so that these are in a perfect straight line and they don’t look like crap whenever you’re done. What you do is you bend the wire up and you take your flux pen and you want to put it on … get it going (this is called “wetting”) — put it on every single one like that. This is an area where the solder actually comes in and you can actually use it for this. Basically get yourself a nice little bead of solder on there and what you’re going to do is get your tabbing wire positioned; now I’m going to use a little clamp to hold it down because this wire does build up some heat. I’ll get the first one in place over here. Now I have two cells that are joined together.
So we’re going to go outside and we’re going to see if this produces one volt real quick. You want to test these as you go along – the time to replace a bad cell is now versus once you’re completely done with your project.
Now the way that you want to test these is you attach your negative lead to the front which is this tabbing wire here and then you can touch pretty anywhere on the back. So you basically take and test it — touch it to the back of this to the meter and we’re getting one volt out of this which is these two together produce the one volt. If I cover them up – they drop. So these two cells are actually good to go.
So what you’re going to have to do in order to get something to charge 12-volt batteries like these over here what you’re going to have to do is you’re going to have to do this 36 times total. So you’re going to need 36 of them to get to the 18 volts that you need.
So this is what we did just now – I got a couple of blisters in the process – and you can see it’s a pretty tedious process to do. Doing it this way comes out to be about $2 a watt, maybe a little bit less than that. As you can see, these are very fragile – they break easily – so you have to encase them really good. You need to put a glass cover over them; you need to seal this so moisture doesn’t get in there. There’s really a lot to the DIY process with this.
To encase it, does somebody “improv” on that or is there a traditional case to use?
Well, we’re going to be doing that in future videos, we’re going to be actually trying different ideas. You basically make a frame, encase it in glass, and seal it so that moisture doesn’t get in there. Some people will seal these in resins or waxes and that’s a good way too. It is a pretty tricky process; I personally don’t really necessarily have the patience to do an entire panel – we’re going to do it for our video.
Well, it seems a little bit hard to get the soldering and the strips on there just right – within time it would come a lot easier.
Well, it’s definitely a practice thing and our soldering iron, by the way, is not a good soldering iron for this. You want to buy a really good one that gets a really good heat buildup to it and it’ll be a lot easier!
It looks great … so somebody would have to get this – how many times would they have to produce this?
To charge a 12-volt battery, you would need to put 36 of them (36 x .5v = 18v no load) together to get to 18-volts or if you wanted 20-volts, you would need to do 40 of these.
So does it go in a row or how does that work?
What people will usually do is 18 of these and then 18 of these and then tie those together so that jumps the voltage up and then the bigger panels if you want to increase; because 36 of these will produce about 60 watts/65 watts (61.2 watts to be exact). The Harbor Freight system that we have outside is 45 watts. So if you put 36 of these together you would have a more powerful system than the Harbor Freight out there (there are complete guides available on the internet). So it would cost you probably about $100 to do that with these cells, the tabbing wire; you have to take into account that you’re going to break some along the way. Then you have to add the case cost to it because sealing these – the Harbor Freight system has been out in the sun, it’s been out in the rain, it’s been dipped in water – some of the smaller panels – and they work fine. This is going to be up to you how well that that works out. And that is a basic overview of how to solder solar cells together for producing electricity..
Can it be embedded in acrylic or is that too…
You could encase this in resin, you can definitely do that – there are different types of resin. You just want to make sure that the contacts all stay good together, that sort of thing. And it’s really important to test these as you go along. You also need to add some blocking diodes to this because you don’t want it to drain your battery; you need to make sure the voltage only goes in one direction.
This process is good for somebody who’s on a budget, who has a lot of time on their hands and who is very patient and wants to do it yourself. If you’re not that type of person, buy a pre-manufactured system. It’s going to cost you probably double or a little bit more than that, but that’s your call with it.
I definitely think it’s worth completing as many as we have and embedding it into something for our future videos.
We spent about $400 on 150 cells, a little bit more than that ($375 = 170 cells, tabbing wire, bus wire, solder and flux pen), and that’s the equivalent of about 300 watts. So if we can get one together, a 300-watt solar panel is – well, we wouldn’t do one, but 300-watts of solar panels is pretty expensive to buy (300 Watts retail pre-manufactured: Mono-crystalline = $2500 or amorphous = $1800).
I think the challenge is worth the effort on it.
You do get better at this by the way, this is like the third one that I did and again, the soldering iron is crappy.
If you go to our website (GreenPowerScience.com), we will have information on where you can buy all of this stuff. There are different people that sell it on eBay, that sort of thing. We’ll have some links to that and you can at least buy some cells, buy some of this stuff and see if it’s for you.
That sounds great!
I’m your host Dan Rohas and I’m Denise Rohas, thank you for watching and enjoy our videos. Oh and don’t grab the soldering iron in the wrong place!
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Other articles you may also enjoy:
http://www.greenjoyment.com/how-to-build-your-own-solar-panel-solar-cell-electricity.html
http://www.greenjoyment.com/wind_turbines_made_simple_how_to_build_your_own_electricity.html
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3 Responses to “Step-by-step DIY Solar Cell Soldering: Green Power Science”
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HI,
I`m so happy to be one of ur fance, infact the web site was so intrested, to some extent that i can now bost building my how sola panel and generate an affordable elcetricity for my family. through the guaid aquiring on this web sit. i real using the meadia to appreciate all ur endless effort. to bring such opportunity to my door step. wishs u long live and more discovery. bye frm daran. -
irvin queen says:
Hi;
Do you have step by step instructions for making Amorphous Solar Cells for sale. I am am Technically able to follow the steps. I teach at a local High School. Please advise. I am intereste in making my own Amorphous Solar Cells (Thin film). Please reply.
Thank you
Irvin queen
thanks a lot for sending me all these step by step guide,am so greatfull to be a member of green power,am trying to save ,for to oder some of the kits,like silver solder lead free,coated tin wire,tabbing wire.am feeling great all these days ahead.