I became interested in solar panels and making my own for my garage so that I could do more household projects. I don't have an electrical degree but with the vast amount of knowledge, tips and tricks regarding building solar panels on the interweb, I wanted to consolidate and share my project with those who are also interested in making a solar panel out of quality materials that will last for more than 15 years.
Step 1: Tools
Box Cutter or Scissors
Metal Working Drill Bits (makes drilling the aluminum a little easier)
Clamps, Makes using the mitre box easier
Sockets (I list these only to be used as weights to weigh down the panels when wiring these in series. This will make more sense later.)
Step 2: Materials
(1 Pack) 9mm X 12 mm Corner brace
(4) 1/16" X 3/4" - 36" Aluminum angle
100% Silicon Caulk
(40 Feet, Minimum) Tabbing Wire
(20 Inches, Minimum) Bus Wire
Flux Pen, Kester #186
Schotky Diode, 6 Amp Axial Type, The last four items came as a set purchase from mlsolar on eBay.
(36) 3" X 6" Solar Panels, I bought from mlsolar on eBay
(1) Solar Tite 386S Silicone Elastomer Solar Cell Encapsulant
Several Feet of 10 AWG wire
Weatherproof 10 AWG connector, I got mine from allelectronics.com
(6) Wing Wire Nuts
(1) 1/4" thick 26 1/2" x 32 1/4"Tempered Glass (I got mine at www.affordablesolarframes.com)
Note: www.affordablesolarframes.com has a bundle where you get the glass and the frame for $112 or you could just get the glass like I did for $75 and make your own aluminum frame for much less than $37. It is up to you if you want to buy the frame with it, granted, it is way better quality than the one I will make here and comes with brackets you can attach to the sides to help mount the finished panel.
You will eventually need to buy a charge controller, Battery (preferably a sealed lead acid type, or deep cycle for more heavy duty power usage), power inverter and if you are Really trying to supplement your electric bill a Grid tie inverter.
Step 3: Solar Power Potential, Overview, and some Electrical Basics
Most power inverters are called Modified Sine Wave Power Inverters, however there are more expensive Pure Sine Wave Inverters. Pure sine wave inverters will be more accomodating for electronic use such as televisions, laptops and gaming systems. These will make the picture more crisp like we are accustomed to and will not be "choppy." If a Grid Tie Inverter is connected, then the opposite end could be plugged into any outlet of your house and the electricity generated by the solar panel will directly supplement your electricity bill. Some solar arrays in the Kilowatt ranges could even drive your electricity meter backwards and feed excess energy back into the grid. (!!! Check with local and state regulations as well as your electric company regarding grid tie inverters for legality purposes!!!)
Wires: Red = Positive (+), Black = Negative (-)
When it comes to wiring electrical components, there is a series and parallel wiring. Wiring in Parallel means the positive wire is connected to another positive wire and the associate negative wire is connected to the other negative wire. Wiring is Series means the positive wire is connected to the negative wire and the associated negative wire is connected to the other positive wire.
Wiring a Battery in series with a second battery will double the output Voltage. Therefore, if you had two 12V, 10 Amp hour Deep Cycle Batteries wired in series, your outcome would be a 24V, 10 amp hour battery bank effectively.
Wiring a Battery in parallel with a seconc battery will double the amp hour usage, Therefore, if you had two 12V, 10 amp hour deep cycle batteries wired in parallel, your outcome would be a 12V, 20 amp hour battery bank effectively.
Now you may be wondering what is the best wiring sceme for a battery bank. First let's do some math...I know! I know! Math!?! but bear with me, it won't be That bad :)
The battery that I use in this instructable is a 12Volt 10 AH (amp hour) battery. That means that, using the power equations for batteries: V*A=Watts, 12V * 10AH = 120 Watt hours. That means that if I had a 60 Watt bulb being powered from the battery directly, 120 WH / 60 Watts = 2 hours worth of use. By dividing Watt Hours by the wattage of the load being utilized, the watt unit of the equation cancels out and leave the amount of time the load can theoretically be used. I am sure there is some sort of tolerance like +/- 10% where you might be able to pulle a few more minutes after the two hour mark or on the flip side, less than two hours
If I wanted to use that 60 Watt load for more time, I could wire another battery in parallel to double the amount of amp hours to 20 AH and therefore have a total of 240 Watt hours. I could then use the 60 watt load for 4 hours now, as opposed to the two hours with just one battery! If you had a DC load that didn't utilize 12 volts but 24 volts instead, you would need to wire the batteries in series so that the output voltage would be 24V.
One final note, If you have a panel wired to some amperage, say 5 Amps, and you have a 10 Amp Hour battery that was dead, it would take about 2 hours to fully charge the battery (provided you have a higher voltage panel compared to the battery, i.e. an 18V panel for a 12V battery like I do in this instructable). I have seen deep cycle batteries in the range of 60AH and, again for example, with the same 5A panel, it would take 12 hours to fully charge the battery.
One final final note on the use of Deep Cycle batteries, these are specifically made to be fully discharged and subsequently fully charged over and over, hence the name. So if you plan on fully discharging the battery over and over or simply don't have the drive to check the battery's life every second you are using it, go with deep cycle batteries.
And that's that! Not too bad, yeah?!
Step 4: The Frame
When I made the cuts, I did so with my mitre box and hacksaw at a 45 degree cut. MAKE SURE you are using the right 45 degree angle because I almost made a wrong one where the inner angle would have been facing outside and would make no sense. I had to use a piece of spare wood to act as a spacer to get the cuts to go all the way through because my mitre box is deep for my hacksaw. However, if you have a bandsaw...lucky you because you could get in done in 5 minutes unlike me who spent hours yelling at my hacksaw in a fit of fatigue.
Next, use a file or grit paper to smooth all the burrs on the edges. I used a marker to know where to drill holes for the corner bracers and drilled them out. Secure the bracers with the screws and due to my hacksaw work, the frame was slightly flimsy but still rigid enough to get the job done.
One final tip is to drill the holes closer to the top edge of the frame and not "IN" the angle. You need room for the tempered glass to fit and if you put the bracers right smack dab in the angle the tolerance may be too too snug for comfort. Drill two holes in the top of the frame for the output wires to come out of for later, as well.
Step 5: Tabbing the Cells
These cells are 0.5V, ~3.5A each and wired in series will...What?? That's Right! make the finished panel 18V, and still ~3.5A! If you just had a panel that was right on 12V and were trying to charge a 12V battery, IT WON'T! You need that extra bump in voltage to keep that difference of potential to charge the battery.
In the materials section, the pic that shows all the tabbing wire in little strips needed to be manually cut myself. Tabbing wire usually comes in a spool and that is why I cut a piece of cardboard 3 inches in dimension. I know what you're thinking, " Why not just cut a 6 inch piece of cardboard since the stripes need to be 6 inches long?" Well I wanted to be sure the wire had a little over 6 inches from looping it around the cardboard because there needs to be a slight gap between cells.
Once you have 72 pieces of tabbing wire, you need to apply a little bit of flux from your flux pen to the two gray strips on the front of the solar cell and use your soldering iron to solder it down like in the first pic. Tabbing wire has solder on it so don't worry about applying more. You will know when the iron is hot enough because the tabbing wire will physically change a bit to fuse to the solar cell.
I tabbed the front of all 36 cells only. I wanted to do this first to test each individual cell against the sun to ensure they were not defective or I didn't overheat them while tabbing or some such fiasco. Testing voltage of the cells early and often prevent a huge headache...no...migraine, later on the in the wiring. The next step is soldering the tabbing wire on the fronts of the panels to the back of the next cell. This is the series wiring as seen in pic two.
Step 6: Solar Cell Wiring
When you have all 4 rows of 9 cells wired up, you will need some extra tabbing wire to go on the back of the butt end of the row. This is so we can bus the rows together. You will notice this on pic 4.
Step 7: The Glass
I wanted to get the glass onto the frame and let it dry while bussing the rows of cells. All you need here is the silicone caulk and apply it to the inside of the frame. Apply it right down the middle to allow it to seep under the glass but not so much where it will "climb" the left wall of the angle or drip out in the front of the glass.
Let me just say that i went with this glass and aluminum combo because of the quality!!! (emphasis on Quality) You do NOT want to use plexiglass or wood or annealed glass for your frame. Plexiglass will scratch with branches and whatnot falling on it. And if you live in the dessert where the sun is plentiful, the dust will jack up the plastic. Annealed glass Will break if too much pressure is applied be it snow build up or other stuff falling on it. And a wood frame WILL warp and Will break your delicate solar cells. I want to reiterate that this solar panel is being made to last for 15 years or more (hopefully more :) )
Apply the silicone to the frame, put on the glass and press down to ensure good contact, let the silicone dry (overnight would definitely be best) and use spacers like spare pieces of wood to protect your floor, carpet or table. Whatever the frame is drying on. You don't want to pull up little pieces of carpet in your dried silicone.
Step 8: Bussing the Cells
The idea here is Keeping the panel in series. (by now, you are probably like, "Geez, I get it already! Series, yeah.") I mentioned that you needed to tab the back of the butt end of the row of cells. This is because your cells are wired back to front, back to front going down the line. So we need to continue this by bussing the rows back to front.
I am heavily refering to my picture here. The bus bars are not soldered in place and are shown to give a roadmap on how to accomplish the series wiring. You will need to flip around two of the four rows and this is why you need to tab the backs of the cells. The bus bars are merely larger versions of their tabbing wire counterparts but I would suggest some additional solder just to ensure the junction between the bus and the tabbing wire.
Step 10: Output Wiring and Encapsulant Preparation
Prep for the resin by adding a border of silicone. This will keep the resin from flowing out to the edge of the glass and on the backs of the panel itself. EVERY DROP OF ENCAPSULANT COUNTS!
Step 11: Encapsulant
The silicone border will help keep the resin in place to get as much as you can on the back of the cells. Eventually the resin will seep into all the nooks and crannies. This is where that pastry brush in the pic comes in handy to spread it all around. You want a good even coat. It is good to have your panel sit in a cool place while it sets. This will take a while and that is good! You want a long set time so that the air bubbles will rise to the top and pop. Bubbles aren't a bad thing but it's best to avoid them. If your resin is taking a long time to set and still feels "sticky" you could set it by a window that gets a lot of sun light.
Use a good Solar! quality resin. Don't go out and get cheap epoxy because after a lot of exposure to direct sun light your panel Will yellow and this Will affect the efficiency of your panel over time. Like I mentioned before, I am building a panel that will last over a decade, not a couple summers!!
PS Don't put cardboard over the back of the panel to protect it while it is drying! It Will SAG, dry and stick to the resin and Will ruin the panel by cracking your cells.
Step 12: Finish Wiring and Enjoy Solar Energy
The panel was then connected to the charge controller, the controller to the battery and then it commenced charging. Within little time, the battery when from an initial charge of 12.8 to 13.3V and stayed there. The charge controller is doing its job then!
And that is that. Solar energy with no CO2 or pollutants powering household devices. As mentioned before, the battery does DC loads and getting an inverter will convert the 12V DC to 120V AC to power electric devices that call for 120V. Getting more batteries wired tegether and fully charged will help with power outages and that way you won't have a noisy gas guzzling generator to worry about. Or you could build more panels and grid tie it directly to the house to supplement your bill (if your power co./state allows).
I hope this clears building your own high quality solar panel up. I just viewed a lot of videos, read a ton of articles and it paided off for me. Building this panel set me back about $150 but compared to buying a quality 60W panel at $250-ish, I'll take it. Building it was actually pretty fun, kept me busy and expanded my electrical know how. I hope this inspires you to build your own and save some money! Enjoy.