Do-it-yourself solar battery. DIY Solar Camping Power Supply Site Selection and Design
Unfortunately, solar panels are not cheap, so you can assemble a homemade solar panel yourself. For
For the manufacture of a solar battery, we use simple tools and inexpensive improvised materials to make a powerful and, most importantly, a cheap solar battery.
What is a solar cell? and with what it is eaten.
A solar cell is a container made up of solar cells.
Solar cells do all the work of converting solar energy into electricity. Unfortunately, a lot of solar cells are needed to get enough power for practical use.
Moreover, solar cells are very fragile. Therefore, they are combined into a solar battery.
A solar cell contains enough solar cells to generate high power and protects the cells from damage.
Difficulties arising in the self-manufacture of a solar battery:
The main obstacle in solar cell manufacturing is purchasing solar cells at a reasonable price.
New solar cells are very expensive and difficult to find in normal quantities at any price.
Defective and damaged solar cells are available from eBay and elsewhere for much less.
"Second-class" solar cells could possibly be used to make a solar cell.
In order to make a solar battery as cheap as possible, we use defective elements and buy them, for example, on eBay.
To make the solar cell, I bought several 3x6 "monocrystalline solar cells.
To make a solar cell, 36 such cells must be connected in series.
Each element generates about 0.5V. 36 cells connected in series will give us about 18V, which will be enough to charge 12V batteries. (Yes, such a high voltage is really necessary for efficient charging of 12V batteries).
Solar cells of this type are paper thin, fragile and brittle like glass. They are very easy to damage. The seller of these items dipped sets of 18 pieces. in wax for stabilization and delivery without damage. Wax is a headache when removing it. If you can, look for non-waxed items. But remember that they may receive more damage in transit.
Note that my cells already have wires soldered. Look for items with wires already soldered. Even with these elements, you need to be prepared to do a lot of soldering iron work. If you buy elements without conductors, get ready to work with a soldering iron 2-3 times more. In short, it is better to overpay for the wires already soldered.
I also bought a couple of non-wax kits from another vendor. These items came packed in a plastic box. They dangled in the box and chipped a little on the sides and corners. Minor chips don't matter much. They won't be able to reduce the cell power enough to worry about. The elements I bought should be enough to assemble two solar panels. Knowing that I might break a couple when assembling, so I bought a little more.
Solar cells are sold in a wide variety of shapes and sizes. You can use larger or smaller ones than my 3x6 inches. Just remember:
Cells of the same type produce the same voltage regardless of their size. Therefore, to obtain a given voltage, the same number of cells is always required.
- Larger cells can generate more current, while smaller cells can generate less current.
- The total power of your battery is defined as its voltage multiplied by the generated current.
Using larger cells will allow you to get more power at the same voltage, but the battery will turn out to be larger and heavier. Using smaller cells will make the battery smaller and lighter, but will not provide the same power.
It is also worth noting that using cells of different sizes in the same battery is a bad idea. The reason is that the maximum current generated by your battery will be limited by the current of the smallest cell, and the larger cells will not operate at full strength.
The solar cells I chose are 3 "x 6" and are capable of generating approximately 3 amperes of current. I plan to connect 36 of these elements in series to get a voltage of just over 18 volts. The result should be a battery capable of delivering about 60 watts of power in bright sunlight.
It doesn't sound very impressive, but it's still better than nothing. Moreover, it is 60W every day when the sun is shining. This energy will be used to charge the battery, which will be used to power lamps and small equipment just a few hours after dark.
The solar panel housing is a shallow plywood box to keep the sides from obscuring the solar cells when the sun shines at an angle. It can be made from 3/8 "plywood with 3/4" slats. The sides are glued and screwed into place.
The battery will contain 36 3x6 "cells.
We divide them into two groups of 18 pieces. just to make them easier to solder in the future. Hence the center bar in the middle of the drawer.
A small sketch showing the dimensions of the solar cell.
All dimensions are in inches. 3/4 '' thick collars run around the entire plywood sheet. The same side goes down the center and divides the battery into two parts.
View of one of the halves of my future battery.
This half will contain the first group of 18 elements. Pay attention to the small holes in the rims. This will be the bottom of the battery (in the photo, the top is at the bottom). These are ventilation holes designed to equalize the air pressure inside and outside the solar array and serve to remove moisture. These holes should only be at the bottom of the battery, otherwise rain and dew will get inside. The same ventilation holes should be made in the center dividing strip.
It is not necessary to use perforated fiberboard sheets, I just had these at hand. Any thin, rigid and non-conductive material will do.
To protect the battery from weather troubles, we cover the front side with plexiglass.
In the photo there are two sheets of plexiglass connected on a central partition. We drill holes around the edge to fit the plexiglass onto the screws. Be careful when drilling holes near the edge of the plexiglass. Do not press hard - otherwise it will break, and if you break it, then glue the broken piece and drill a new hole near it.
We paint all wooden parts of the solar battery in 2-3 layers to protect them from environmental influences. We paint the box and substrates from 2 sides inside and outside.
The base for the solar cell is ready, and now is the time to prepare the solar cells.
As mentioned above, removing wax from solar cells is a real headache.
To effectively remove wax from solar cells, use the following method:
1) We bathe solar cells in hot water to melt the wax and separate the cells from each other. Do not let the water boil, otherwise the steam bubbles will forcefully beat the elements against each other. Boiling water may also be too hot, and electrical connections in the cells may be broken.
I recommend immersing the elements in cold water and then heating them slowly to prevent uneven heating. Plastic tongs and a spatula will help separate the pieces as the wax melts. Try not to pull too hard on the metal conductors - they may break.
The photo shows the final version of the "setup" that I used.
The first "hot tub" for melting the wax is in the background on the right. In the foreground on the left is hot soapy water, and on the right is clean hot water. Temperatures in all pans are below the boiling point of water. First, melt the wax in a distant saucepan, transfer the elements one by one into soapy water to remove wax residues, and then rinse in clean water.
2) Lay out the items to dry on a towel. You can change soapy water and rinse water often. Just do not empty the used water down the drain, as the wax will harden and clog the drain. This process removed almost all of the wax from the solar cells. Only some have thin films left, but this will not interfere with the soldering and operation of the elements. Washing with a solvent will probably remove any residual wax, but it can be dangerous and smelly.
Several separated and cleaned solar cells are dried on a towel. After separating and removing the protective wax, because of their fragility, they become surprisingly difficult to handle and store, we leave them in the wax until you are ready to install them in the solar panel.
Making the basis for the solar battery. It's time for me to install them.
We draw a grid on each base to simplify the process of installing each element.
We lay out the elements on this grid with the back side up, so they can be soldered together. All 18 cells for each battery half must be connected in series, after which both halves must also be connected in series to obtain the required voltage.
Soldering the elements together is difficult at first. Start with only two elements. Place the connecting wires of one so that they intersect the solder points on the back of the other. Be sure to make sure that the spacing between the elements matches the markup.
For soldering, we use a low-power soldering iron and rosin-core solder bar.
Soldering had to be repeated until a chain of 6 elements was obtained. I soldered the connecting bars from the broken elements to the back of the last element in the chain. I made three such chains, repeating the procedure twice more. A total of 18 cells for the first half of the battery.
Three strings of elements must be connected in series. Therefore, we rotate the middle chain 180 degrees in relation to the other two. The orientation of the chains is correct (the elements are still lying with their backs up on the substrate). The next step is to glue the elements in place.
Gluing the elements will take some skill. Apply a small drop of silicone sealant to the center of each of the six elements of the same chain. After that, we turn the chain face up and place the elements according to the markings that were applied earlier. Press down lightly on the elements, pressing in the center to adhere them to the base. Difficulties arise mainly when flipping a flexible chain of elements. A second pair of hands won't hurt here.
Do not apply too much glue and do not glue the elements anywhere other than the center. The elements and the substrate on which they are mounted will expand, contract, bend and deform as temperature and humidity change. If you glue the element all over the area, it will break over time. Gluing only in the center gives the elements the freedom to deform separately from the base. The elements and the base can deform in different ways and the elements will not break.
Here is a fully assembled half of the battery. A copper braid from the cable was used to connect the first and second strings of elements.
You can use special busbars or even ordinary wires. I just had a copper braid from the cable at hand. We make the same connection on the reverse side between the second and third chain of elements. With a drop of sealant, I attached the wire to the base so that it would not "walk" or bend.
Test of the first half of the solar panel in the sun.
In a dim sun in haze, this half generates 9.31V. Hooray! Working! Now I need to make another half of the same battery.
After both bases with elements are ready, they can be installed in place in the prepared box and connected.
Each of the halves is placed in its place. To fix the base with the elements inside the battery, we use 4 small screws.
We pass the wire for connecting the halves of the battery through one of the ventilation holes in the central side. Here, too, a couple of drops of sealant will help secure the wire in one place and prevent it from dangling inside the battery.
Each solar array in the system must be equipped with a blocking diode in series with the battery.
The diode is needed to prevent the discharge of batteries through the battery at night and in cloudy weather. I used a 3.3A Schottky diode. Schottky diodes have a much lower voltage drop than conventional diodes. Accordingly, there will be less power loss on the diode. A set of 25 diodes of the 31DQ03 brand can be purchased on eBay for just a couple of bucks.
We connect diodes to solar cells inside the battery.
We drill a hole in the bottom of the battery closer to the top to bring the wires out. The wires are tied in a knot to prevent them from being pulled out of the battery, and secured with the same sealant.
It is important to let the sealant dry before we attach the plexiglass in place. I advise based on previous experience. Silicone fumes can form a film on the inside of the plexiglass and elements if you do not allow the silicone to dry outdoors.
Solar battery in operation. We move it a couple of times a day to keep it oriented towards the sun, but it's not that difficult.
Let's calculate the cost of making a solar battery:
We consider only the cost of basic materials, improvised (pieces of wood, wires
1) Solar cells bought on eBay $ 74.00 (~ 2300 rub.)
2) Wood - 15 $ (~ 460 rubles.)
3) Plexiglas 15 $ (~ 460 rubles.)
4) Screws and self-tapping screws - $ 2 (~ 60 rubles)
5) Silicone sealant - $ 3.95 (~ 150 rubles)
6) Wires $ 10 (~ 300 rubles)
7) Diodes 2 $ (~ 60 rubles.)
8) Paint 5 $ (~ 150 rubles)
Total $ 126.95 (~ 3640 rubles)
For comparison, an industrial-made solar battery of similar power costs about $ 300-600 (~ 9000-18000 rubles.
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In the first photo, there are four panels that generate a little over 2 volts, which is at least 6.5 volts in total without the sun, and more than 8 volts in the sun. The maximum current in bright sun reached 7A, which is not even bad for a portable portable socket. For tests, I placed these panels on the roof, brought the wires to the attic, where I will further show all the measurements of testing this solar battery.
Why did I decide to make a solar panel from several parts? Just the task was to make a portable panel that was supposed to be foldable and weigh a little, while I want to increase the power to 100 watts to power a laptop, charge any other electronics (phone, flashlight, etc.).
I looked on the Internet how solar panels are made and it turns out that almost everyone uses glass. But glass is simply unacceptable for a portable solar battery because, firstly, glass is heavy and easy to break. The search was aimed at plexiglass and after the search, the choice fell on acrylic glass, since the manufacturer promises more than 10 years of operation without loss of quality and, most importantly, it should not become cloudy in the sun.
In order to glue the elements to the glass and at the same time seal them, I decided to use a film that is used for outdoor advertising. I chose an expensive option with a declared long service life under the influence of the environment. Now I have 4 solar batteries, a little later I will make 3 more and there will be a full-fledged powerful panel for charging lead-acid batteries.
Solar panel manufacturing process.
Pak was waiting for acrylic glass, he soldered elements of 4 pieces in series and fixed them on the sheets of ecobont. As the glass came, the work continued. Before rolling the elements under the film, I first thoroughly cleaned them with alcohol and cotton wool from dust and flux residues.
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Then he carefully peeled off the pieces of adhesive tape that held the elements on the ecobone.
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I removed the protective film from the acrylic on one side.
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Now the preparation for rolling the elements into the film.
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I cut off a piece of film to the desired length.
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The process of gluing the film, this must be done slowly and very carefully so that folds and irregularities do not form, while it is better not to press hard on the elements, otherwise they may crack, they are very fragile.
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Here I am cutting through the pins from the elements. By the way, the right hand in the glove is not accidental, it is just that the glove glides better on the film and it is more convenient to smooth the film.
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Well, the panel is almost ready, it remains to remove the protective film from the acrylic.
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So the first assembly is ready, I'm conducting a performance test using an LED flashlight, the voltage on the voltmeter is 1.8 volts, which means the battery is working. Using the same principle, I assembled three more panels and later placed them on the roof.
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To test the battery in the attic, I placed two multimeters, a pointer for volts, and a digital one for amperes. As a result, the largest current recorded 7.2A amperes, which is even unexpected from such seemingly small panels. That's basically all for now.
When writing the article, materials were used >> source
It all started with a walk on eBay - saw solar panels and got sick.
Arguments with friends about payback were ridiculous…. Buying a car, no one thinks about payback. Auto as a mistress, prepare the amount for pleasure in advance. And here, on the contrary, I spent money so they are also trying to pay off ... In addition, I connected an incubator to the solar panels, so they still justify their purpose, protecting your future economy from destruction. In general, having an incubator, you depend on many factors, here either a master or a layman. When there is time, I will write about a homemade incubator. Well, okay, why talk, everyone has the right to choose ... ..!
After a long wait, the treasured box with thin fragile plates finally warms the hands and heart.
First of all, of course, the Internet ... well, it's not the gods who burn the pots. The experience of someone else is always useful. And then disappointment came ... .. As it turned out, five people made the panels with their own hands, the rest were simply copied to their sites, some of them in order to be copied from different developments in an original way. Well, God bless them, let it remain on the conscience of the owners of the pages.
I decided to read the forums, long arguments of theorists "how to milk a cow" led to complete despondency. Discussions about how the plates break from heating, the difficulty of sealing, etc. I read and spat on the whole thing. We will go our own way, by trial and error, relying on the experience of "colleagues", why reinvent the wheel?
We set the task:
1) The panel should be made of scrap materials, so as not to pull the wallet, because the result is unknown.
2) The manufacturing process should be easy.
We start making a solar panel:
First of all, 2 glasses of 86x66 cm were purchased for the future two panels.
Plain glass, purchased from manufacturers of plastic windows. Or maybe not simple ...
A long search for aluminum corners, according to the experience already tested by "colleagues", ended in nothing.
Therefore, the manufacturing process began sluggishly, with a feeling of protracted construction.
I will not describe the process of soldering the panels, since there is a lot of information about this on the network and there is even a video. I'll just leave my notes and comments.
The devil is not so terrible as he is painted.
Despite the difficulties that are described on the forums, the element plates are easily soldered, both the front side and the back. Also, our Soviet POS-40 solder is quite suitable, in any case, I did not experience any difficulties. And of course, our dear rosin, where without it ... During the soldering time I did not break a single element, I think you have to be a complete idiot to break them on even glass.
The conductors that come with the panels are very convenient, firstly, they are flat, and secondly, they are tinned, which significantly reduces the soldering time. Although it is quite possible to use an ordinary wire, I conducted an experiment on spare plates, I did not experience any difficulties in soldering. (in the photo there are remnants of a flat wire)
It took me about 2 hours to solder 36 plates. Although I read on the forum that people solder for 2 days.
It is advisable to use a soldering iron for 40 watts. Since the plates easily dissipate heat, and this makes soldering difficult. The first attempts to solder with a 25 Wadded soldering iron were boring and sad.
Also, when soldering, it is advisable to optimally select the amount of flux (rosin). For a large excess of it does not allow the tin to stick to the plate. Therefore, I had to practically tin the disc, in general, it's okay, everything is fixable. (take a closer look at the photo you can see.)
Tin consumption is quite high.
Well, in the photo there are soldered elements, there is a jamb in the second row, one output is not soldered, but I noticed and corrected the main thing.
The edging of the glass is made with double-sided tape, then a plastic film will be glued to this tape.
Scotch tapes that I used.
After soldering, start sealing (tape will help you).
Well, the glued plates with scotch tape and a fixed joint.
Next, remove the protective layer of double-sided tape from the edging of the panel and glue a plastic film on it with a margin on the edges. (I forgot to take a picture) Oh, yes, we make slots in the scotch tape for outgoing wires. Well, not stupid, you will understand what and when ... Along the edge of the glass, as well as the leads, corners, we coat with silicone sealants.
And we fold the film to the outside.
A plastic frame was pre-made. When I installed plastic windows in the house, a plastic profile for the window sill is attached to the window with screws. I thought this part was too thin. Therefore, he removed and made the sill in his own way. Therefore, plastic profiles remained from 12 windows. So to speak, the material is in abundance.
I glued the frame with an ordinary, old, Soviet iron. It's a pity I didn't shoot the process, but I think there is nothing beyond the incomprehensible. I cut off 2 sides at 45 degrees, heated it on the sole of the iron and glued it, having previously installed it at an even angle. In the photo there is a frame for the second panel.
We install glass with elements and a protective film in the frame
We cut off the excess film, and glue the edges with silicone sealants.
We get just such a panel.
Yes, I forgot to write that, in addition to the film, I glued guides to the frame that prevent the elements from falling if the adhesive tape comes off. The space between the elements and the guides is filled with polyurethane foam. That made it possible to press the elements more tightly to the glass.
Well, let's start testing.
Since I made one panel in advance, the result of one I know is the Voltage of 21 Volts. Short circuit current 3.4 Ampere. The strength of the charging current of the storage battery is 40A. h 2.1 Ampere.
Unfortunately I didn’t take pictures. I must say that the current strength depends on the illumination.
Now 2 batteries connected in parallel.
The weather at the time of production was cloudy, it was about 4 o'clock in the afternoon.
At first it upset me, and then it even made me happy. After all, these are the most average conditions for a battery, which means the result is more believable than in bright sun. The sun shone through the clouds not so brightly. I must say that the sun was shining a little from the side.
With this lighting, the short-circuit current was 7.12 Amperes. Which I consider to be an excellent result.
No-load voltage 20.6 Volts. Well, that's stable at about 21 volts.
The battery charge current is 2.78 Ampere. That, with such lighting, guarantees a battery charge.
Measurements have shown that with a good sunny day, the result will be better.
By that time, the weather was getting worse, the clouds were closed, the sun was completely and I wondered what it would show in this situation. It's almost evening twilight ...
The sky looked like this, specially shot the horizon line. By the way, on the very glass of the battery you can see the sky like in a mirror.
The voltage in this situation is 20.2 volts. As already mentioned 21c. it is practically a constant.
Short circuit current 2.48A. In general, it is great for such lighting! Almost equal to one battery in good sun.
The battery charge current is 1.85 Ampere. What can I say ... Even at dusk, the battery will be charged.
Conclusion built solar battery, not inferior in characteristics to industrial designs. Well, the durability ... .., we will look, time will tell.
Oh yes, the battery is charged through 40 A Schottky diodes. Well, what was found.
I also want to say about controllers. All this looks nice, but not worth the money spent on the controller.
If you are friends with a soldering iron, the circuits are very simple. Make and have fun making.
Well, the wind blew and the remaining spare 5 elements fell into an uncontrollable flight ... ... the result was splinters. Well what to do, carelessness should be punished. On the other hand…. Where are they?
We decided to make another socket out of the fragments, volt by 5. It took 2 hours to make. The remnants of the materials just came in time. Here's what happened.
Measurements were taken in the evening.
I must say that with good lighting, the short-circuit current is more than 1 ampere.
The pieces are soldered in parallel and in series. The goal is to provide approximately the same area. After all, the current strength is equal to the smallest element. Therefore, when manufacturing, select elements according to the area of \ u200b \ u200bthe illumination.
Now is the time to talk about the practical application of the solar panels I have made.
In the spring, I installed two fabricated panels on the roof, height 8 meters at an angle of 35 degrees, oriented to the southeast. This orientation was not chosen by chance, because it was noticed that in this latitude, in the summer, the sun rises at 4 am and by 6-7 o'clock it quite tolerably charges the batteries with a current of 5-6 amperes, also applies to the evening. Each panel must have its own diode. In order to exclude burnout of elements with different power of the panels. And as a result, an unjustified decrease in the power of the panels.
The descent from a height was made with a stranded wire with a cross section of 6mm2 each. Thus, it was possible to achieve minimal losses in the wires.
Old barely-living batteries 150Ah, 75Ah, 55Ah, 60Ah were used as energy storage devices. All batteries are connected in parallel and taking into account the loss of capacity, they total about 100Ah.
There is no battery charge controller. Although I think the installation of the controller is necessary. I'm working on the controller circuit now. Since the batteries start to boil during the day. Therefore, you have to dump excess energy daily by turning on unnecessary load. In my case, I turn on the sauna lighting. 100 watts. Also, during the day, an LCD TV of about 105W, a fan of 40W works, and an energy-saving 20W light bulb is added in the evening.
For those who like to carry out calculations, I will say: THEORY AND PRACTICE are not the same thing. Since such a "sandwich" works perfectly fine for over 12 hours. At the same time, sometimes we charge phones from it. I have not yet reached the full discharge of the batteries. Which, accordingly, crosses out the calculations.
As a converter, a computer uninterruptible power supply (inverter) 600VA, slightly altered for free starting from batteries, was used, which approximately corresponds to a load of 300W.
I also want to note that the batteries are charged even when the moon is bright. At the same time, the current is 0.5-1 Ampere, I think it's not bad at all for the night.
Of course I would like to increase the load, but this requires a powerful inverter. I plan to make the inverter myself according to the diagram below. Since buying an inverter for a lot of money is INSANE!
So, before the vacation, the task was once again to provide marching power supply for a variety of electronic devices that I carry with me. For example - GPS navigator, player, phone... Last year I got a so-called. "Vampire" (I want to solder my own, better) - a device that is an MK with a body kit, the task of which is "Pull" energy from batteries and feed to the output for recharging the recipient device. But again there was no particular desire to lug a supply of AA batteries with me, so I decided to feed the "vampire" batteries, charged, in turn, from the energy of the Sun.
The original idea is very simple and easy to follow. In order not to search solar panels at various radio stores - we go to the nearest hypermarket and buy the simplest solar-powered garden lights. In my case, the batteries were donated by Kosmos flashlights - the cheapest that we could find. Manufacturing solar mobile chargers from such lamps - it is simple and quick. I managed two lanterns in an hour.
The raw material looks like a solar panel connected to an LED power circuit and a single AA battery compartment. The kit comes with a 400 mAh battery - complete rubbish, it is better to immediately replace it with a more capacious one.
The first step is to carefully solder the terminals of the solar battery (hereinafter - "SB") from the battery compartment (hereinafter - "battery compartment"). Further, the SB terminals must be stripped of insulation by about 5-7 mm and irradiated. The main element of the device is ready!
Step two - with no less care we solder the LED power supply circuit (printed circuit board with a body kit and the LED itself) from the battery compartment. We no longer need the circuit (unless you want to make something useful out of this "recyclable material" in the future, for example - LED desk lamp, I decided to use them for this). So, at the moment we have panel sat with conclusions and battery compartment without them. There is little to do - to collect all this goodness together!
However, before the final assembly, it would be nice to make sure that the solution we applied is working. Then it will be too late to redo something! So, literally "on snot" we connect the SB terminals to the corresponding contacts of the battery compartment (the black wire is " — ", Red - " + ", It must be connected to the" spring "and" pimp "on the battery compartment, respectively). We take it in hand tester(he is - multimeter) and check the presence on the power circuit, as well as the voltage at the entrance to the battery compartment. The tester shows 1.98 V in fairly low natural light (my windows are to the west, direct sunlight does not pass), while the operating voltage of the battery is 1.2 V... From which we can conclude that 1.98V charging current is sufficient to charge an AA battery. Later, this conclusion was confirmed by practice - the batteries were successfully charged and no less successfully gave energy to my mobile gadgets.
Now that the performance of the selected circuit is confirmed by the measurement results, you can proceed to the final assembly! It is necessary to carefully solder the SB terminals to the corresponding inputs of the battery compartment (for convenience, I used extension conductors). I insulated and protected the soldering points with a thermal gun(I filled it with molten polyethylene, to put it simply). You can also use a shrink sleeve (cambric) for this.
