As a promise is a debt and I have received many requests for translations of the manual, I have translated it myself (no Google translator and with a lot of sweat...) so that you can understand it perfectly, here you go:
The characteristics of this solar panel are, 60w power, 3A of current and 12v of tension, for little more than 70 €The price of a shop with the same characteristics is well over 200 €Nothing to envy. In addition you have all the confidence of ComoHacer.eu since we ourselves sell the materials so that you can make it.
What is a solar panel? It is basically a box containing a set of solar cells. Solar cells do the actual work of converting sunlight into electricity. However, it takes a lot of cells to create significant power, and they are very fragile, so individual cells are mounted on panels with several of them. The panels have enough cells to make a good amount of energy while protecting the cells from the elements.
I have bought a pair of 3×6 inch mono-crystalline cell blocks (we have them in our official shop for the best price). You need a total of 36 of this type of solar cells connected in series to make a complete panel. Each cell produces approximately half volt. 36 panels of these would give approximately 18 v that would be used to carry 12 v batteries (Yes, you need these 18 v to be able to charge a 12 v battery effectively). This type of solar cell is so fina like paper and as fragile like glass. They are very easy to break.
There are many types of cell sizes in addition to the 3 x 6 inches. You can use whatever size you think is best for the manufacture of your panel, you just have to keep a few things in mind:
- Cells of the same type produce the same voltage no matter what size they are. Therefore, they will always be the same number of cells.
- Larger cells produce more current (amperes) and smaller cells produce less current.
- The total power of your panel is determined by the formula, P (power) = V (voltage) x I (intensity).
Therefore, the use of large cells will give more powerbut the assembly will be heavier and the use of smaller cells will make the panel lighter, but produce less. In addition, it is not advisable to put cells of different sizes together.. This will cause the smaller ones to limit their panel so that the larger ones will not operate at full power.
These cells of 3×6 incheshave an intensity of 3 A . As I said before, I put 36 of these in series to obtain 18 v more or less. Calculating, with these characteristics, we should get about 60 W power with normal sunshine. It doesn't sound like much in principle, but the main use of this panel will be to run throughout the day to power batteries that will then provide a few hours of light at night. When you buy the cells and have them at home, make sure you store them in a safe place away from children and pets so that they don't break and become useless.
A solar panel is actually a perfect square, in this case two perfect squares. I made the panel so that the edges of the panel do not shadow the cells. It is made with a wooden plate of 3/8 inch thick plywoodplus pieces of ¾ x ¾ at the edges. The pieces are glued and screwed in place. The complete panel will have 36 cells 3 x 6 inches. I preferred to do two groups of 18 cells each other to make assembly easier. Therefore, there should be a divider in the middle of both panels and fit perfectly into the gaps.
This is the sketch I made so you can see the exact dimensions of each part of the panel. All dimensions are in inches. The parts ¾ x ¾ go all the way around the panel and divide it down the middle. This is the way I decided to do it, feel free to change anything, as it won't affect the way it works.
Here is a sample of about half of the main panel. This will have 18 cells inside. See the holes at the bottom of the panel (yes, that's the bottom). These are ventilation holes to keep the air pressure inside the panel equal to that outside and to allow moisture to escape. These holes should be at the bottom of the panel or rain or dew could damage it by getting inside. There should also be ventilation holes in the centre divider between the two sub-groups.
The next step was to cut two pieces of holed wood and place them perfectly inside the two openings. These pieces will support both sub-panels. They should be screwed together. If you do not have this type of wood at hand, you can use any other similar type of material that does not conduct current.
In order to protect the solar cells from the weather, the panel shall have a plexiglass on top. Here I used two pieces of plexiglass I had lying around. Glass could also be used, but it is much more fragile. This would be the result without the mounted cells.
In this picture you can see how the edge of the plexiglass on the centre divider has broken while I was drilling with a 1 inch drill bit. Be careful when working in these areas as they are very delicate places.
I then applied several coats of paint to all the woodwork to protect it from the weather and humidity. The reason for the choice of colour is no other than the availability of this paint in my garage.
Now that the panel structure is finished, it is time to get the solar cells ready.
As I said before, getting the solar cells with wax was a real headache. After some trial and error, I found a way that works quite well. The first step is a bath in hot water to melt the wax and separate the cells from each other. Don't let the water boil or the bubbles will knock the cells into each other abruptly. Also, boiling the water may cause the cell connections to separate. I also recommend putting the cell block into the cold water and gradually heating the water to just before boiling point (100°C) to avoid violent heat shocks. Have a pair of tweezers at hand to carefully remove the cells from the water. Try not to pull too hard on the metal tabs so as not to break them. In my opinion, this is the worst way to separate the cells, but I had no choice.
This photo shows the complete configuration I used. The first hot water bath for wax melting is the one at the back right. On the left, in front, is the hot water and soap bath. On the right, also in front, is the hot water bath. All are in the pots just before the boiling point. First we would put the cell blocks in the top right pot, to melt all the wax, then we would put it in the bottom left one, which contains soap, and finally we would put it in the last pot to clean the remains, this pot contains hot water only. Dry the cells with a towel. I recommend that you change the water frequently for clean water. If, after this process, there is still some wax left over, you can apply a little solvent to it.
In this picture we have the cells drying out, at this point, they are very fragile and we have to have very careful when handling them. Now it is time to mount the cells on the panel.
First I drew with a pencil a grid with the 18 cells on the perforated panel where we will place them later. Later I placed them upside down to be able to solder them together. We have to solder them in series and then find a way to join both blocks. Solder it as you see in the picture and make sure that the space you leave between cells is the same for the rest.
Use a soldering iron low power and give it a coat of tin before you start soldering to make it easier, give it a little at a time so you don't break it or overheat it, and don't push it too much either.
I repeated the above step two more times until I have 3 rows of 6 cells eachThe total of 18 cells makes up half of the entire panel.
The 3 groups of 6 cells must be connected in series, so we must place the middle one upside down (rotated 180). Keep in mind that we have them upside down, so we will have to see what position we want them to be in when they are in their original position.
The gluing of the cells is a bit difficult due to the fragility of the cells. Put a small drop of hot silicone in the centre of each cell and glue it little by little on the perforated panel we had saved (following the drawn grid, of course). Press a little on each cell to make it stick better. We recommend another pair of hands for this task.
Do not use too much glue, not everywhere, only on your centres. This will give you more mobility for overheating and expansion. If you put too much glue and leave them fixed, you are likely to crack over time.
Here is half of the finished panel.
For the interconnection of the cell lines, I have used stranded copper wire, one at the top and one at the bottom in the picture. Then you can fix it with some hot silicone.
This is the first test I did with half of the panel, as you can see, with almost no sun, it gives a little more than half the voltage of the whole group (9.31v), that's good. Now all I had to do was to set up another one like that.
When I have the two panels complete, I can interconnect them in series and mount them in the wooden crate.
On each side of the panel, I left a hole so that I could place some screws that would help me to anchor them firmly to the board, four in total for each half panel.
Remember the ventilation holes between the panels, well those are the holes I used to interconnect one panel to the other. Once again, when we have them interconnected, we will fix all the wires with hot silicone.
Every solar power system needs a blocking diode in series with the panels to prevent the panel from discharging the batteries at night or on very cloudy days. In this case I have used a Schottky diode with an endurance of 3.3 amps. This type of diode has a lower loss than rectifier diodes, hence the reason for using them. Every watt counts. We have them included in the pack we sell in our shop.
Initially, my plan was to mount the diode in series with the positive cable out of the box, but then, reading the specifications of the diode, I realised that it was more efficient the hotter it was, so I I mounted it inside. A little bit of silicone to fix it and that's it.
I made a hole in the back-top of the board to pass the output cables. The knot is to prevent the connections from being broken by a pull, a bit of silicone and that's it.
It is important that the hot silicone is allowed to dry completely before the plexiglass is fitted, as the vapours from the silicone can create a thin layer on the inside of the plexiglass, which can reduce sunlight penetration.
We will put more hot silicone on the cable outlet.
Finally, all we need to do is to put the plug that suits us best at the end of the cables, and start using it!!!!
Here is the finished panel with the plexiglass screwed on but not sealed in case any repairs had to be made after the fire test. After testing we can seal it with whatever we like, silicone, tape or any other adhesive.
The test fire gives an excellent tension (18,88v with winter sun and no load). The intensity is also very good (3 A with the same conditions).
The total cost of the solar panel is €69.95, including the charge controller. A pittance compared to what you can save with it, and we also have the components available to make a charge controller if you want to buy it separately.
And now it's off to the countryside to try it out, nice, eh?
Too difficult, you can always go on Amazon and look at prices of professional solar panels already mounted.
- Buy the materials needed to make the solar panel in our official shop and the charge controller.
- Frequently asked questions about the solar panel(FAQ's); Link.
- You may also be interested in; How to make a charge controller.
- You may also be interested in; How to make a wind turbine.
- Full tutorial PDF in Spanish created by How to do; Link.
- Tutorial of the solar panel original in English; Link.