DIY solar panel: step by step instructions, detailed video. DIY solar panels How does a solar battery work at home

Today many owners country houses busy looking for alternative sources of electricity. The installation of solar panels is gradually gaining its popularity. However, not everyone can afford to purchase expensive equipment. Therefore, many are wondering: how to make solar panels with your own hands? The correct answer will be revealed in this article.

Solar battery - a device that converts solar energy into permanent electricity

A solar battery is a semiconductor device that converts solar radiation into electrical energy. The main task of such a system is a reliable, economical and uninterrupted power supply at home. It is advisable to install such devices in areas where there are interruptions in the supply from the main source of electricity.

The main advantages of a solar battery are:

simple installation of the device, which does not require laying cables to the supports;
the system does not require large time costs for its maintenance;
electricity generation does not have a detrimental effect on the environment;
the design has no moving parts;
silent mode of operation;
the supply of electricity does not depend on the distribution network;
long period of operation of the system at minimal cost.

Disadvantages of a solar battery:

the manufacturing process of the system is very laborious;
the solar panel takes up a lot of space;
the device is very sensitive to contamination;
the battery does not work at night;
The efficiency of the device directly depends on weather conditions, namely on sunny and cloudy days.

The principle of operation of the solar battery

The system works by means of photoelectric converters, which are connected in a certain sequence. Each photoconverter consists of two silicon wafers, which differ in the type of conductivity. One is covered with phosphorus, as a result of which an excess of negatively charged electrons is formed here. The other plate is coated with boron, which leads to the formation of particles that are absent in the layer of negative charges, the so-called "holes".

The principle of operation of an inexhaustible source of alternative energy is as follows: sunlight hits a negatively charged panel, which leads to the active formation of additional "holes" and electrons. The phosphor coated panel contains electric field which results in a potential difference. Positively charged particles rush to the top layer, and negatively charged particles go to the bottom. A constant voltage is created. It turns out that one converter works like a battery. In the chain there is D.C. when a load is attached to it. Each battery is covered with thin copper veins that drain current and direct it to its intended purpose.

The current strength depends on certain parameters:

photoconverter size;
insolation level;
photocell type;
the total resistance of the devices that are connected to the solar panel.

Varieties of solar panels

All solar panels can be silicon or film. Panels based on silicon are divided into types:

polycrystalline;
monocrystalline;
amorphous.

The polycrystalline solar cell is a dark blue square device. Its surface is interspersed with inhomogeneous silicon crystals. Despite the low efficiency of 18%, this device has the ability to generate current during cloudy weather, which makes them indispensable in areas dominated by scattered sunlight.

Monocrystalline solar power converters feature bevelled black panels using pure silicon. All cells of the device are directed in one direction, which allows you to get a maximum efficiency of 25%. The disadvantage of such batteries is that their front side must always be facing the sun. If it did not have time to ascend, hid behind the clouds and fell below the horizon, the solar panels will produce a low power current. This is the most expensive, but also providing maximum performance, type of device.

Each amorphous battery consists of many thin layers of silicon, which are obtained by spraying the smallest particles of the material onto glass, plastic or foil. Such layers quickly burn out, which in six months leads to a drop in the efficiency of the device by 15-20%. The efficiency of such converters is only 6%. They are the cheapest and are able to work even in cloudy weather. However, their maximum service life is 2 years.

Film batteries are based not on a solid metal or glass substrate, but on a polymer film. Therefore, they are produced in rolls, which allows you to spread the batteries over large areas. Due to their design, they can be cut into various shapes and sizes, and solar panels can be placed on the roof of the house with smooth curves. They are compact and lightweight. A rolled panel will cost significantly less than a silicon panel, which uses expensive material to manufacture. However, these models are less powerful. It is quite difficult to buy them today, since production is only developing.

All solar panels, regardless of the type of device, are equipped with controllers that monitor the degree of charge of the panel. They redistribute the received energy, directing it to the source of consumption directly or storing it in a battery.

Solar panels for a private house

This alternative to traditional power supply is very practical. In addition, the price of the device is significantly different from the cost of electricity. Having made a solar battery for the house with his own hands, the owner will be able to optimize power consumption and thereby reduce his own cash costs. Many people want to understand in advance how much it will cost to install solar panels for a private house. To do this, it is necessary to carry out preliminary calculations, which determine the required power of the equipment and the conditions for its operation.

You should start by calculating the amount of energy consumed, which is necessary to provide housing. When creating a full-fledged station, it is worth focusing on batteries of 150-250 W, for country house 50 watt panels will suffice.

This value is the basis for the subsequent determination of the number of solar panels and the number of auxiliary equipment, which includes batteries, inverters and controllers.

Helpful advice! It is worth adding another 20% to the total need for electricity, which is spent in the batteries themselves.

An important aspect is insolation, i.e. the amount of solar energy that falls on a separate unit of panel area. This value is individual for each specific region. You can get it in special literature or on specialized meteorological sites.

The energy norm is divided by the value of insolation. The resulting figure must be divided by the total capacity of the solar installation. The resulting value is the number of batteries needed. Here it is important to get maximum number panels. After all, in different months the amount of sunlight will be different.

Helpful advice! Since insolation is constantly changing, calculations should be made monthly.

For example, if you need to find out how many solar panels are needed for a house of 100 sq.m., where the station will power lighting bulbs, a laptop, a TV, a satellite dish, and an electric stove, all the above calculations should be performed. As a result, the power of the solar station will be approximately equal to 1000 W, which implies the use of 4 solar panels with a power of 250 W each.

The panel must be placed on the southern part of the roof, which must be in perfect condition and able to withstand a solid load. There should be no trees or other objects nearby that create a shadow.

Such a system can be used not only for power supply. Heating with solar panels of a private house is gaining great popularity. This allows you to get rid of the expensive service associated with centralized gas supply, get rid of dependence on utilities, and receive year-round heat over the long life of a solar power plant.

The installation of such a system is advisable only for those regions where the sun shines at least 20 days a month. If the sun is not enough for the system to provide full heating of the house, it can be used as an additional free source. A properly selected system of solar panels for heating a house will pay for itself in 3-4 years.

Solar panels for the home: consumer reviews

Thanks to the numerous positive reviews about an alternative source of electricity, it is possible to dispel the myths that worry potential installers.

Many people think that such expensive equipment will not pay for itself throughout the life of the installation. However, as practice shows, correct installation solar panels in compliance with all the rules can be provided a private house electricity for at least 25 years. And the cost of the equipment will pay off in 3-4 years.

The following myth implies inefficient operation of solar panels in cloudy weather or in winter period time. However, the opinions of consumers agree that solar collectors are able to show maximum activity during the stay of the sun at its zenith in cloudless weather. But when the sun hides behind the clouds, the panels will work, but not in full. The installation completely stops working at night when there is no sunlight at all.

Opponents of solar panels argue that solar collectors are quite fragile and are not able to withstand the various loads created by nature. However, consumer reviews prove the opposite: the solar panel is able to withstand even large hail.

Related article:

Presented technical requirements for the installation of solar panels. Features of selection and installation. Manufacturers overview.

The next myth concerns snow, which can block light from reaching the system. However, here the danger is hoarfrost, for which snow will cling and create barriers. To avoid this, you can place the batteries on the house vertically, then you can avoid a lot of gliding light.

And the last myth concerns the Chinese production of solar panels. Despite a very solid range of products, factories in China often produce high-quality goods. This is especially true for the manufacture of solar collectors and heat pipes, the production of which is 90% concentrated in China. These products have high technical characteristics and are certified not only in their own country, but also in Germany.

Numerous positive reviews on the Internet prove that an alternative source of electricity is good not only for a private home. Many successfully use solar panels for an apartment, which are installed on a balcony. They can be fixed directly on the glass or in the glazing frame, which will play the role of tinting.

Sets of solar panels 3 kW for the cottage from 60,000 rubles

In the country, as a rule, there are electrical appliances of small power, where a limited number of batteries and a small frequency of their use are required. If there is no centralized power supply in the country house, then it is advisable to install a set of solar panels that will generate electricity for free. However, to get such free pleasure, you will initially have to spend money on a purchase. necessary materials, the cost of which will pay off only after a few years.

For the production of 1 kW of electricity, a kit with a capacity of more than 200 watts is required. According to numerous reviews, solar power plants for a country house with a capacity of 800 W are capable of providing a complete autonomous power supply to an object. The cost of such a system will cost from 80,000 rubles.

A standard set of a solar power station for a summer residence consists of 200 W panels, a 40 A charge controller, a 3 kW inverter, two 200 A batteries and other auxiliary parts. The price of such a kit starts from 60,000 rubles, and the approximate payback period is 3-5 years. However, this is the most profitable way to generate electricity for facilities without a centralized power supply. It is less expensive than using a diesel generator.

According to the reviews of the owners, solar panels for the house on suburban area it is better to equip with two or four modules with a power of 200 V each. It depends on the number of energy consumers, the duration and frequency of their use. If the power is not enough, it can be increased by adding solar panels.

Many people purchase such a kit for the private sector, where there is a centralized power supply, such as additional source energy. Numerous reviews of solar panels for the home indicate that in this case, you can significantly save on paying electricity bills.

How to make solar panels with your own hands

When it is not possible to purchase a ready-made solar station, you can create it yourself. There are two options here: purchase ready-made modules and connect them to a battery with an inverter, or solder the panel yourself. The first assembly method is fast, but more expensive. The second option requires a certain skill of the assembler, who must be extremely careful with fragile photocells.

Four solar panels generate a total of 2 volts of electricity

To create a solar battery for your home with your own hands, you need to prepare certain materials.

The first main component for creating solar panels is a set of high-quality photocells. Today you can buy elements made of polycrystalline or monocrystalline silicon. More popular are the latest photovoltaic cells, which are ideal for home energy supply.

Helpful advice! All the elements necessary for assembly should be purchased from one manufacturer. Since the materials of different brands are significantly different, which will complicate the assembly of the entire structure.

To connect the photocells, a set of special conductors is required. For the manufacture of the case of the future battery suitable aluminum corners weather resistant. The housing size depends on the number of photocells. It is better to use transparent polycarbonate or plexiglass as an external coating of photocells, which prevent penetration infrared rays. As additional materials, you will need mounting hardware, copper electrical wires, Schottky diodes, silicone vacuum stands and a set of screws for fastening.

In addition to the FEP, you need to buy a 12 V to 200 V inverter for the house, which converts direct current to alternating current. For the accumulation and slow consumption of electricity, a pair of gel or AGM batteries is needed. An equally important element is the controller, which is necessary to disconnect the battery from the battery during its full charge and turn it on to receive a new portion of electricity.

You can also assemble a solar battery with your own hands from improvised means. Diodes, foil or transistors are suitable for this. The operation of a solar battery from diodes occurs as a result of the appearance of a voltage of about 2.5 V under direct sunlight. However, when the sun is not enough, this indicator begins to drop rapidly, and the diodes themselves begin to consume energy. Using such a battery is ineffective.

The foil device is more suitable for the production of thermal energy. Also, foil is an ideal material for FEP substrate. The most efficient is a solar battery assembled from transistors. The more their number, the higher the power of the device. The upper part of each transistor must be cut off, pour out the powder. The output of the device are contacts. This battery is designed to power your phone. For more serious events, its power is not enough.

Do-it-yourself solar panels for the home: step-by-step instructions for making

After all the necessary elements are prepared, you can begin to assemble the structure, which consists of the following steps:

Creation of a frame from aluminum corners with low sides and hardware, the size of which depends on the number of transducers and their area. Here it is necessary to take into account the distance between the solar cells of at least 5 mm.
Sealant should be applied to the inner edges of the rails.
Lay a sheet of transparent material, tightly engrafting it to the adhesive contour.
After the sealant has completely dried, use hardware to fasten the frame and the transparent surface.
Lay out on a flat surface all the photocells of the battery with the “negative” side up.
With the help, conductors of the same length are connected to each FEP. It is most convenient to do this when the module is placed on the glass.
All elements are sequentially connected to each other in the form of a "snake".
The extreme contacts must be soldered to the bus (silver wide conductor).
To prevent a decrease in the quality of lighting at night, it is necessary to create "midpoints" using shunt diodes that are installed on the positive terminal. Schottky diodes are suitable for this.
Lay photocells with conductors on a transparent plane.
Lubricate all solar cells, output and connecting wires with silicone glue.
Close the structure with the back panel.
Connect the solar panel to the battery, solar charge controller and inverter.

Helpful advice! So that between load and separate elements the battery has not been short-circuited, fuses must be installed.

Almost every homeowner wants to get free electricity. Installing solar panels is the most acceptable option. Using this device, you can create a main (without centralized power supply) and an additional source of electrical energy. The system is environmentally friendly and reliable to use. The main disadvantage is expensive equipment. However, its cost will pay off in 3-5 years.

Getting electricity from alternative power sources is very costly. For example, the use of solar energy when buying ready-made equipment will have to spend a significant amount of money. But nowadays it is possible to assemble solar panels with your own hands for a summer residence or a private house from ready-made photovoltaic cells or other improvised materials. And before you start buying the necessary components and designing the structure, you need to understand what a solar battery is and how it works.

Solar battery: what is it and how does it work

People who are faced with this task for the first time immediately have questions: “How to assemble a solar battery?” or "How to make a solar battery?". But having studied the device and the principle of its operation, the problems with the implementation of this project disappear by themselves. After all, the design and principle of operation are simple and should not cause difficulties when creating a power source at home.

Solar battery (SB)- These are photoelectric converters of energy emitted by the sun into electrical energy, which are connected in the form of an array of elements and enclosed in a protective structure. Converters- silicon semiconductor elements for direct current generation. They are produced in three types:

Monocrystalline;
polycrystalline;
Amorphous (thin film).

The principle of operation of the device is based on the photoelectric effect. Sunlight, falling on photocells, knocks out free electrons from the last orbits of each atom of the silicon wafer. The movement of a large number of free electrons between the electrodes of a battery generates a direct current. Further, it is converted into alternating current to electrify the house.

Choice of photocells

Before the beginning design work to create a panel at home, you need to choose one of three types of solar energy converters. To select the appropriate elements, you need to know their technical characteristics:

Monocrystalline. The efficiency of these plates is 12–14%. However, they are sensitive to the amount of light entering. Slight cloudiness significantly reduces the amount of electricity generated. Service life up to 30 years.
Polycrystalline. These elements are capable of producing an efficiency of 7–9%. But they are not affected by the quality of illumination and they are able to deliver the same amount of current in cloudy and even cloudy weather. Operational period - 20 years.
amorphous. Manufactured from flexible silicon. They produce an efficiency of about 10%. The amount of electricity produced does not decrease due to the quality of the weather. But expensive and complex production makes them difficult to obtain.

For the manufacture of SBs on their own, you can purchase type B converters (second grade). These include cells with small defects, even if you replace some components, the cost of batteries will be 2-3 times less than the market price, thanks to this, save your money.

To provide a private house with electricity from an alternative energy source, the first two types of plates are best suited.

Site selection and design

Batteries are best placed according to the principle: the higher the better. A great place would be the roof of the house, it does not get a shadow from trees or other buildings. If the structure of the ceilings does not allow to support the weight of the installation, then the place should be chosen in the area of \u200b\u200bthe cottage, which most of all perceives radiation from the sun.

The assembled panels must be placed at such an angle that the sun's rays fall as perpendicularly as possible on the silicon elements. The ideal option there will be the possibility of correcting the entire installation in the direction behind the sun.

Making a battery with your own hands

You will not be able to provide a house or cottage with electricity at 220 V from a solar battery, because. the size of such a battery will be huge. One plate generates an electric current with a voltage of 0.5 V. The best option is considered to be a SB with a rated voltage of 18 V. Based on this, the required amount photocells for the device.

Frame assembly

First of all, a homemade solar battery needs a protective frame (case). It can be made from aluminum corners 30x30 mm or from wooden bars at home. Using metal profile on one of the shelves, a chamfer is removed with a file at an angle of 45 degrees, and the second shelf is cut off at the same angle. Frame parts cut to the required dimensions with machined ends are twisted using squares made of the same material. A protective glass is glued to the finished frame on silicone.

Plate soldering

When soldering elements at home, you need to know that to increase the voltage it is necessary to connect in series, and to increase the current strength - in parallel. The flint wafers are laid out on the glass, leaving a gap of 5 mm between them on each side. This gap is necessary to compensate for the possible thermal expansion of the elements during heating. The converters have two tracks: on the one hand "plus", on the other - "minus". All parts are connected in series in a single circuit. Then the conductors from the last components of the circuit are output to a common bus.

To avoid self-discharge of the device at night or cloudy weather, experts recommend installing a 31DQ03 Schottky diode or equivalent on the contact from the “middle” point.

After finishing soldering work with a multimeter, you need to check the output voltage, which should be 18-19 V to fully provide a private house with electricity.

Panel assembly

Soldered transducers are placed in the finished case, then silicone is applied to the center of each silicon element, and the top is covered with a fiberboard substrate to fix them. After that, the structure is closed with a lid, and all joints are sealed with sealant or silicone. The finished panel is mounted on a holder or frame.

Solar panels from improvised materials

In addition to assembling SBs from purchased photocells, they can be assembled from improvised materials that any radio amateur has: transistors, diodes and foil.

transistor battery

For these purposes, the most suitable parts are transistors of the type KT or P. Inside them is a rather large silicon semiconductor element necessary for the production of electricity. Having picked up the required number of radio components, it is necessary to cut off the metal cover from them. To do this, you need to clamp it in a tesk and carefully cut off the upper part with a hacksaw for metal. Inside you can see a plate that will serve as a photocell.

Transistor for a battery with a sawn-off cap

All these parts have three contacts: base, emitter and collector. When assembling the SB, you need to choose a collector junction due to the largest potential difference.

Assembly is carried out on a flat plane from any dielectric material. You need to solder transistors in separate series chains, and these chains, in turn, are connected in parallel.

The calculation of the finished current source can be made from the characteristics of radio components. One transistor produces a voltage of 0.35 V and a short-circuit current of 0.25 μA.

Diode battery

A solar battery made of D223B diodes can indeed become a source of electric current. These diodes have the highest voltage and are made in a glass case coated with paint. The voltage at the output of the finished product can be determined from the calculation that one diode in the sun generates 350 mV.

We put the required number of radio components in a container and fill it with acetone or another solvent and leave it for several hours.
Then, you need to take a plate of the right size from a non-metallic material and mark up for soldering the power supply components.
Once wet, the paint can be easily scraped off.
Armed with a multimeter, in the sun or under a light bulb, we determine the positive contact and bend it. Diodes are soldered vertically, since in this position the crystal generates electricity best from the energy of the sun. Therefore, at the output we get the maximum voltage that the solar battery will generate.

In addition to the two methods described above, the power supply can be assembled from foil. A homemade solar battery, made according to the step-by-step instructions described below, will be able to produce electricity, albeit of very low power:

For homemade, you will need copper foil with an area of \u200b\u200b45 square meters. see. The cut piece is processed in a soapy solution to remove fat from the surface. It is also advisable to wash your hands so as not to leave grease stains.
It is necessary to remove the protective oxide film and any other type of corrosion from the cut plane with emery.
A sheet of foil is placed on the burner of an electric stove with a power of at least 1.1 kW and heated until red-orange spots form. Upon further heating, the resulting oxides are converted into copper oxide. This is evidenced by the black color of the surface of the piece.
After the formation of oxide, heating must be continued for 30 minutes in order to form an oxide film of sufficient thickness.
The frying process stops and the sheet cools down along with the oven. With slow cooling, copper and oxide cool at different rates, which makes it easy for the latter to peel off.
Under running water oxide residues are removed. In this case, it is impossible to bend the sheet and mechanically tear off small pieces so as not to damage the thin layer of oxide.
The second sheet is cut according to the size of the first.
In a plastic bottle with a volume of 2–5 liters with a cut neck, two pieces of foil should be placed. Secure them with crocodile clips. They need to be positioned so that they do not connect.
A negative terminal is connected to the processed piece, and a positive terminal is connected to the second one.
Salt solution is poured into the jar. Its level should be 2.5 cm below the upper edge of the electrodes. To prepare the mixture, 2-4 tablespoons of salt (depending on the volume of the bottle) are dissolved in a small amount of water.

All solar panels are not suitable for providing a summer house or a private house with electricity due to their low power. But they can serve as a power source for radios or charge small electrical appliances.

The choice of photocells for a solar battery

Polycrystalline or single crystal. There is no single answer, polycrystalline modules are cheaper, but they have lower energy efficiency. Most industrial manufacturers prefer polycrystalline solar cells. In Russia, neither one nor the other is produced, therefore we make purchases on com or aliexpress.com.
Dimension. Available in 6x6(156x156mm), 5x5(127x127mm), 6x2(156x52mm) inches. You should take the latter. The fact is that all photocells are very thin and fragile, they break easily during installation, so it is more profitable to break a small photocell. Also, the smaller the size of one element, the easier it is to fill the area of the battery.
Soldered contacts. Each plate will be connected in series with the others, so there will be a lot of work with the soldering iron. Soldered contacts to the panels greatly facilitate this work. Connecting such contacts to a common bus will be much easier. If there are no such contacts, you will have to solder them yourself.

Tools and materials

Materials:

Aluminum corner 25x25;
Bolts 5x10 mm - 8 pcs;
Nuts 5 mm - 8 pcs;
Glass 5-6 mm;
Glue - sealant Sylgard 184;
Adhesive sealant Ceresit CS 15;
Polycrystalline photocells;
Flux felt-tip pen (a mixture of rosin and alcohol);
Silver tape for connection to photocells;
Tire tape;
Solder (you need a thin one, because excessive heating will disable the photocell);
Polyurethane foam (foam rubber), 3 cm thick;
Dense polyethylene film 10 microns.

Tool:

File;
Hacksaw with blade 18;
Drill, 5 and 6 mm drills;
Open-end wrenches;
soldering iron;

Step by step photo instruction

It is described in as much detail as possible how to assemble a solar battery from photocells on an aluminum frame with your own hands.

File the corners on one edge on each side of the 45 degree aluminum corner.

Trim the corners with a hacksaw at 45 degrees. For convenience, you can use the chair:

On each side of the corner, you should get something like this:

Cut aluminum corner

We make brackets for connecting the corners:

We attach the corners with cut corners to each other
We put a corner perpendicularly and on it we outline a cutting line You should get 4 connecting corners

On the sides of each bracket received, we find the center and drill a hole with a diameter of 6 mm:

Finding the center of each side of the bracket
Hole in bracket

We make markings through the hole in each bracket on the corner. In order not to confuse later, we mark each corner and each bracket with a number:

Marking holes "in place"
We put the numbers so as not to confuse later

We drill holes in the corner with a 5 mm drill, it should turn out like this:

Holes in the corner

We assemble the frame with bolts and nuts:

We glue the glass into the assembled frame using sealant:

Silicone should be treated joints outside and inside

Degrease the glass surface from the inside and arrange the photocells face down so that the contact bars are parallel:

Connect the photocells together with adhesive tape, so they will not fall apart during further operations.

Connect the elements according to the scheme:

Connection diagram of photocells in a battery

We assemble the sealing structure:

Cut out a rectangle from a sheet of polyurethane foam, 1 cm less than the inside of the frame on each side;
We solder the resulting rectangle into a plastic film using adhesive tape or a soldering iron.

The design fits inside the frame:

Foam rubber fits inside the frame

The frame, together with the foam rubber, is turned over and removed. Only photocells stacked and fastened together with adhesive tape remain:

Remove aluminum frame
Photocells on foam rubber

Sealant Sylgard 184 is applied to the entire surface of the photocells with a brush and covered with a frame with glass on top:

Sealant on photocells
Cover the photocells with a frame with glass

We put the load on the glass for several hours, during which time air bubbles should be removed:

Bubbles go away in 2-3 hours

After 12 hours, we remove the load and tear off the foam rubber. The battery is ready to connect!

Errors when assembling a solar battery with your own hands

A few common mistakes made in self assembly panels that I would like to warn about.

Assembly on a frame made of wood or chipboard. A do-it-yourself solar battery pays off only if it lasts for several years, so an unreliable construction made of timber is definitely not suitable for it, because. swell and lose shape in a year or two. The design is bulky and heavy, difficult to transport and transfer.
Careless storage of Sylgard 184. If you do not use up the entire can of this glue, after use it must be moved to a smaller container so that the residue does not have contact with the air inside it. Otherwise, after six months of storage, all the glue may harden.
The use of plexiglass. The battery is always in the sun (this is its essence), so it gets very hot. Plexiglas very poorly removes heat from photovoltaic cells. This reduces their effectiveness. Each degree above 25°C reduces efficiency by 0.45%. But this is not the main minus of plexiglass! At temperatures above 50 ° C, it deforms in all planes, breaking the contacts inside the circuit, depressurizing the battery and rendering it unusable.
Insufficient attention to the isolation of connections. When assembling solar panels for your home with your own hands, it is better to use special connectors (MC4) that connect several panels into a single network. The fact is that in the future, they may have to be dismantled for repair, turning in the other direction, replacing elements, etc. Twist the contacts "tightly" or use for this purpose the connecting terminals that are designed for internal works- not nai the best option.

Comments:

Solar battery: what is it

Mankind has been on fire with the idea of transforming solar radiation into electrical energy since the 30s of the last century. It was then that scientists from the Academy of Sciences of the USSR announced the creation of semiconductor copper-thallium crystals, in which, under the action of light rays, an electric current began to flow. Today, this phenomenon is known as the photoelectric effect and is widely used both in solar power plants and in a variety of sensors.

The first solar panels have been known since the 50s of the last century.

The current strength of one photocell is measured in microamperes, therefore, in order to obtain any significant electrical power, they are combined into blocks. Many of these modules form the basis of a solar battery (SB), which can be used to connect various electronic devices. If we talk about a finished device that can be installed outdoors, then it is more correct to talk about a solar panel (SP) with a design that protects the assembly of photovoltaic modules from external factors.

It must be said that the efficiency of the first electric solar systems did not even reach 10% - both the shortcomings of semiconductor technology and the fatal losses associated with the reflection, scattering or absorption of the light flux affected. Decades of hard work of scientists have paid off, and today the efficiency of the most modern solar panels reaches 26%. As for promising developments, here it is even higher - up to 46%! Of course, an attentive reader may object that other power generators operate with an energy efficiency of 95-98%. Nevertheless, we should not forget that we are talking about completely free energy, the value of which on a sunny day exceeds 100 watts per square meter. m of the earth's surface per second.

Modern solar panels generate electricity on an industrial scale

The electricity obtained with the help of solar panels can be used similarly to that obtained at conventional power plants - to power various electronic devices, lighting, heating, etc. The only difference, which is that the output of the photoelectronic module has a constant, not an alternating current, is actually an advantage. The thing is that any solar system works only during daylight hours, and its power very much depends on the height of the sun above the horizon. Since the SB cannot work at night, electricity has to be stored in batteries, and they are all just sources of direct current.

Device and principle of operation

The principle of operation of an electric battery is based on such physical phenomena as semiconductivity and the photoelectric effect. At the heart of any solar cell are semiconductors, the atoms of which lack electrons (p-type conductivity), or have an excess of them (n-type). In other words, a two-layer structure is used with an n-layer as the cathode and a p-layer as the anode. Since the holding forces of the "extra" electrodes in the n-layer are weakened (the atoms do not have enough energy for them), they are easily knocked out of their places when bombarded by light photons. Further, the electrons move into the free "holes" of the p-layer and through the connected electrical load (or battery) return to the cathode - this is how the electric current flows, provoked by the flow of solar radiation.

The conversion of solar energy into electrical energy is possible due to the photoelectric effect, which Einstein described in his works.

As noted above, the energy from one photocell is extremely small, so they are combined into modules. By connecting several such blocks in series, the battery voltage is increased, and by parallel, the current is increased. Thus, knowing the electrical parameters of one cell, it is possible to assemble a battery of the required power.

The electricity received from the solar battery can be stored in batteries and, after being converted to a voltage of 220 V, can be used to power conventional household appliances.

To protect against atmospheric action, semiconductor modules are installed in a rigid frame and covered with glass with increased light transmission. Since solar energy can only be used during daylight hours, batteries are used for its accumulation - you can spend their charge as needed. Inverters are used to increase the voltage and adapt it to the needs of household appliances.

Video: how a solar panel works

Classification of photovoltaic modules

Today, the production of solar panels goes in two parallel ways. On the one hand, there are photovoltaic modules based on silicon on the market, and on the other hand, film modules created using rare earth elements, modern polymers and organic semiconductors.

Silicon solar cells popular today are divided into several types:

monocrystalline;
polycrystalline;
amorphous.

For use in homemade solar panels, it is best to use polycrystalline silicon modules. Although the efficiency of the latter is lower than that of single-crystal elements, their performance is not so strongly affected by surface contamination, low cloudiness or the angle of incidence. sun rays.

It is not difficult to distinguish polycrystalline silicon modules from monocrystalline ones - the former have a lighter blue tint with pronounced "frosty" patterns on the surface. In addition, the type of photovoltaic plates can be determined by their shape - a single crystal has rounded edges, while its closest competitor (polycrystal) is a pronounced rectangle.

As for batteries made of amorphous silicon, they are even less dependent on weather conditions and, due to their flexibility, are practically not subject to the risk of damage during assembly. However, their use for their own purposes is limited as a fairly low power density per 1 square meter surface, and because of the high cost.

Silicon solar cells are the most common class of electrical photoplates, so they are most often used to make homemade devices.

The emergence of film photovoltaic modules is due both to the need to reduce the cost of solar panels, and the need to get more productive and durable systems. Today, the industry is mastering the production of thin solar modules based on:

cadmium telluride with an efficiency of up to 12% and a cost of 1 W is 20–30% lower than that of single crystals;
copper and indium selenide - efficiency 15–20%;
polymer compounds - thickness up to 100 nm, with efficiency - up to 6%.

It is still too early to talk about the possibility of using film modules to build an electric solar station with your own hands. Despite the affordable cost, only a few companies are engaged in the manufacture of telluride-cadmium, polymer and copper-indium photocells.

Such advantages of film photocells as high efficiency and mechanical strength allow us to say with full confidence that they are the future of solar energy

Although you can find batteries created using film technology on sale, for the most part they are presented in the form of finished products. We are also interested in individual modules from which you can build an inexpensive home-made solar panel - they are still in short supply on the market.

Summary data on the efficiency of solar cells, which are produced by the industry, are presented in the table.

Table: Efficiency of modern solar panels

Where can I get photocells and can they be replaced with something else

Buying monocrystalline or polycrystalline wafers suitable for assembling a solar panel is not a problem today. The question is that the very idea of a home-made generator of free electricity implies a result that will be much cheaper than the factory counterpart. If you buy photovoltaic modules on the spot, then you won’t be able to save much.

On foreign trading floors, solar cells are presented in a wide range - you can buy both a single product and a set of everything necessary for assembling and connecting a solar battery

For a reasonable price, solar cells can be found on foreign marketplaces, such as eBay or AliExpress.. There they are presented in a wide range and quite affordable prices. For our project, for example, common polycrystalline plates of 3x6 inches are suitable. Under ideal conditions, they can generate an electric current with a voltage of 0.5 V and a power of up to 3 A, that is, 1.5 W of electrical power.

If you are burning with the desire to save as much as possible or try your own strength, then there is no need to immediately buy good, whole modules - you can get by with substandard ones. All on the same eBay or AliExpress, you can find sets of plates with small cracks, chipped corners and other defects - the so-called "B" class products. On specifications ah photocells, external damage does not affect, which cannot be said about the price - defective parts can be bought 2-3 times cheaper than those that have a presentation. That is why it is rational to use them to test the technology on their first solar panel.

When choosing photoelectronic modules, you will see elements various types and size. Don't think that the larger their surface area, the higher the voltage they produce. This is wrong. Elements of the same type generate the same voltage regardless of size. What can not be said about the strength of the current - here the size is crucial.

Although it is possible to use an obsolete component base as photocells, the opened diodes and transistors have too low voltage and current strength - thousands of such devices will be needed

Immediately I want to warn you that it makes no sense to look for an analogue among various improvised electronic devices. Yes, you can get a working photoelectronic module from powerful diodes or transistors taken from an old radio or TV. And even make a battery by connecting several of these elements in a chain. However, it will not be possible to power anything more powerful than a calculator or an LED flashlight with such a “solar panel” due to the too weak technical characteristics of a single module.

The principle of calculating battery power

To calculate the required power of a home-made electric solar system, you need to know the monthly electricity consumption. It is easiest to determine this parameter - the amount of electricity consumed in kilowatt-hours can be viewed by the meter or found out by looking at the bills that the energy sales company regularly sends. So, if the costs are, for example, 200 kWh, then the solar battery should generate about 7 kWh of electricity per day.

In calculations, it should be taken into account that solar panels generate electricity only during daylight hours, and their performance depends both on the angle of the Sun above the horizon and weather conditions. On average, up to 70% of the total amount of energy is generated from 9 am to 4 pm, and in the presence of even a slight cloudiness or haze, the power of the panels drops by 2–3 times. If the sky is covered with solid clouds, then at best you can get 5-7% of the maximum capacity of the solar system.

According to the energy efficiency graph of the solar battery, it can be seen that the main share of the generated energy falls on the time from 9 to 16 hours.

Given all of the above, it can be calculated that to produce 7 kWh of energy under ideal conditions, you need an array of panels with a power of at least 1 kW. If we take into account the decrease in productivity associated with a change in the angle of incidence of rays, weather factors, as well as losses in batteries and energy converters, then this figure must be increased by at least 50-70 percent. If we take into account the upper indicator, then for this example a solar panel with a power of 1.7 kW will be needed.

Further calculation depends on which photocells will be used. For example, take the previously mentioned 3˝×6˝ polycrystalline cells (area 0.0046 sq. m) with a voltage of 5 V and a current of up to 3 A. To collect an array of photovoltaic cells with an output voltage of 12 V and a current of 1,700 W / 12 V = 141 A, you will need to connect 24 elements in a row (a serial connection allows you to sum up the voltage) and use 141 A / 3 A = 47 such rows (1,128 plates). The area of the battery with the most dense laying will be 1,128 x 0.0046 = 5.2 square meters. m

In order to accumulate and transform solar energy into the usual 220 volts, you will need an array of batteries, a charge controller and a step-up inverter

To accumulate electricity, batteries with a voltage of 12 V, 24 V or 48 V are used, and their capacity should be enough to accommodate the same 7 kWh of energy. If you take common 12-volt lead batteries (far from the best option), then their capacity should be at least 7,000 Wh / 12 V = 583 Ah, that is, three large batteries of 200 ampere-hours each. It should be borne in mind that the efficiency of batteries is no more than 80%, and also that when the voltage is converted by an inverter to 220 V, from 15 to 20% of energy will be lost. Therefore, you will have to buy at least one more of the same battery to compensate for all losses.

To the question of the possibility of using electric solar panels for heating

As you may have already noticed, the phrase "solar battery" or "solar panel" is constantly mentioned in the context of an electrical device. This was not done by chance, since other solar panels or batteries - geocollectors - are often called in the same way.

Several solar collectors can provide a house hot water and will bear part of the heating costs

The ability to directly convert the energy of solar radiation directly into heat can significantly increase the productivity of such installations. Thus, modern geocollectors with a selective coating of vacuum tubes have an efficiency of 70–80% and can be used both in hot water supply systems and for space heating.

The design of the solar collector with vacuum tubes minimizes heat transfer to the external environment

Returning to the question of whether an electric solar panel can be used to power heating appliances, let's consider how much heat is needed, for example, for a house of 70 square meters. meters. Based on standard recommendations of 100 W of heat per 1 sq. m of the area of the room, we get the cost of 7 kW of energy per hour, or approximately 70 kWh per day (heating devices, after all, will not be turned on all the time).

That is 10 homemade batteries with a total area of 52 sq.m. Imagine a colossus, say, 4 m wide and more than 13 m long, as well as a block of 12-volt batteries with a total capacity of 7200 ampere-hours? Such a system will not even be able to reach self-sufficiency before the battery life is exhausted. As you can see, it is still too early to talk about the advisability of using solar panels for heating purposes.

Choosing a place for installing an electric solar panel

It is necessary to choose a place where the solar panel will be installed at the design stage. This can be either a south-facing roof slope, or an open area on suburban area. The latter, of course, is preferable for several reasons:

the solar panel installed at the bottom is easier to maintain;
on the ground it is easier to mount the rotary device;
additional load on the roof and its damage during the installation of the solar system is excluded.

Installation location electrical panel should be open to sunlight throughout the daylight hours, so there should be no trees or buildings nearby, the shadow of which could fall on its surface.

When choosing a place to install a solar system, be sure to take into account the possibility of shading solar panels by surrounding objects.

The second circumstance, forcing us to look for such a site before assembling the solar battery, is related to determining the dimensions of the panel. By assembling the device with our own hands, we can be quite flexible in choosing its dimensions. As a result, you can get an installation that fits perfectly into the exterior.

Let's start making a solar battery with our own hands

Having made all the necessary calculations and having decided on a place for installing a solar battery, you can begin to manufacture it.

What will be needed at work

In addition to the purchased solar cells, when building an electric solar panel, you will need the following materials:

copper stranded wire;
solder;
special tires for connecting the outputs of photocells;
Schottky diodes, designed for the maximum current of one cell;
solder;
wooden slats or aluminum corners;
plywood or OSB;
Fiberboard or other rigid sheet dielectric material;
plexiglass (you can use polycarbonate, anti-reflective ultra-clear glass or IR-absorbing window glass with a thickness of at least 4 mm);
silicone sealant;
self-tapping screws;
antibacterial impregnation for wood;
Oil paint.

When choosing glass for a solar panel, you should choose IR-absorbing grades with maximum light transmission and minimum light reflection.

To work, you need this simple tool:

soldering iron;
hacksaw or jigsaw;
a set of screwdrivers or a screwdriver;
paint brushes.

If an additional bracket will be built under the solar panel or swivel support, then, accordingly, the list of materials and tools should be replenished with a wooden bar or metal corners, a steel bar, welding machine etc. When installing the SB on the ground, the site can be concreted or tiled.

Instructions for the progress of work

As an example, consider the process of building an electric solar system from the above-mentioned 3x6 solar cells with a voltage of 0.5 V and a current of up to 3A. To charge a 12-volt battery, it is necessary that our battery “give out” at least 18 V, that is, 36 plates are needed. The assembly should be carried out in stages, otherwise errors in the work cannot be avoided. It should be remembered that any alterations, as well as excessive manipulations with photocells, can damage them - these devices are characterized by increased fragility.

To make a full-fledged solar battery, you will need several dozen photocells.

Case manufacturing

The solar battery case is a flat box closed with plywood on one side and transparent glass on the other. For the manufacture of the frame, you can use both aluminum corners and wooden slats. The second option is easier to work with, so for the manufacture of your first panel, we recommend choosing it.

When starting to build a solar panel, make a small drawing - in the future this will help save time and avoid errors with dimensions

From rails with a section of 20x20 mm, a rectangular frame is assembled with external dimensions 118x58 cm, reinforced with one cross member.

The solar panel is wooden shield with sides no more than 2 cm high - in this case, they will not obscure the photocells

In the lower ends of the body, as well as in the spacer bar, they drill ventilation devices. They will communicate the inner cavity with the atmosphere, so that the glass will not fog up from the inside. After that, a rectangle is cut out of the Plexiglas sheet, corresponding to the external dimensions of the frame.

Holes made in the rails serve to ventilate the interior space of the panel

The back side of the box is sewn up with plywood or OSB. The body is treated with an antiseptic and painted with oil paint.

To protect the wooden case from atmospheric influences, it is painted with oil paint.

According to the size of the internal cavities of the body, 2 substrates for photocells are cut out. Their use during the installation of plates will not only make work more convenient, but also reduce the risk of damage to fragile glass. For substrates, you can take any dense material - fiberboard, textolite, etc. The main thing is that it does not conduct electric current and resists heat well.

Any suitable dielectric can be used as substrates for photocells, for example, perforated fiberboard

Plate Assembly

The assembly of the plates begins with unpacking. Often, for the safety of photocells, they are collected in a stack and filled with paraffin. In this case, the products are immersed in a container with water and heated in a water bath. After the paraffin is melted, the plates should be separated from each other and dried well.

Removal of wax from the plate pack is best done in a water bath. The method shown in the figure has not proven itself in the best way - when boiling, the plates begin to vibrate and hit each other

The photocells are laid out on the substrate in such a way that their leads are directed in the right direction. In our case, all 36 plates are connected in series - this will allow us to “gain” the 18 V we need. For ease of installation, 6 plates should be soldered, getting 6 separate chains.

Before soldering, the photocells are laid out in chains of the required length.

Knowing the principle of forming solar panels, you can easily select the required voltage and current strength. Everything is very simple: first, a group of series-connected plates is assembled, which will give the desired voltage. After that, the individual blocks are connected in parallel - in this case, their current strength will be summed up. Thus, you can get a panel of any power.

Solder is applied to the conductive paths of the photocells and the parts are connected to each other using a low-power soldering iron.

When buying cheaper photovoltaic cells without leads, be prepared for the painstaking work of soldering conductors

After collecting all six groups, a drop of silicone sealant must be applied to the center of each plate. The photocell strings are then unfolded and carefully glued to the substrate.

To fix the photocells on the substrate, use silicone sealant or rubber glue.

A Schottky diode is soldered to the positive terminal of each chain - it will protect the battery from being discharged through the panel at night or during heavy cloud cover. Using a special bus or copper braid, individual blocks are connected into a single circuit.

In the electrical connection diagram, the elements of the solar panel are circled with a dotted line

With a serial connection, the positive output must be connected to the negative contact, and with a parallel connection, to the one of the same name.

Installing plates in the body

The photocells assembled on the substrate are placed in the case and fixed to the plywood using self-tapping screws. Separate parts of the solar battery are connected to each other by a copper conductor. It can be passed through one of the ventilation holes in the cross member - so there will be no interference when installing the glass.

A multi-core cable is soldered to the “plus” and “minus”, which is brought out through a hole in the bottom of the case - it will be needed to connect the panel to the battery. To prevent damage to the plates, the cable is firmly fixed to the wooden frame.

After installing the plates, all hinged elements are fixed with hot glue or sealant.

From above, the solar battery is covered with a sheet of plexiglass, which is fixed with corners or self-tapping screws. To protect the photocells from moisture, a layer of silicone sealant is applied between the frame and glass. On this, the assembly can be considered complete - you can take the solar battery to the roof and connect it to consumers.

After laying and fixing the glass cover, the solar panel is ready for operation.

The efficiency of the solar battery depends on its orientation to the sun - the maximum power is achieved when the sun's rays fall at a right angle. To increase the productivity of the installation, it is placed on a swivel frame. This design is a wooden or metal frame mounted on a swivel horizontal axis.

For maximum efficiency, the solar panel must be oriented directly to the Sun. This task is best handled by automatic installations called solar trackers.

To rotate and fix the frame, you can use either a mechanical drive (for example, a chain drive) or a step-adjustable retaining bar. The most advanced rotary devices are equipped with a rotation unit in vertical plane and an automatic solar tracking system. Such equipment can be assembled using stepper motors and a modern microcontroller, such as Arduino.

Building a solar tracker at home is an extremely difficult task, so most often craftsmen get by with a simple frame with an inclined or fixed frame

Connecting a solar battery to an autonomous power supply system should be done using a charge controller. This device will not only correctly distribute the flows of electrical energy, but also prevent deep discharge of the battery, increasing its service life. All connections, including the connection of the 220V inverter, must be made copper wires with a cross section of at least 3-4 square meters. mm - this will avoid ohmic energy losses.

The solar battery charge controller will allow it to work with maximum current output and protect the batteries from excessive discharge.

Finally, I would like to recommend that you monitor the solar battery not only by indicators and instrument arrows. Be aware that dirty glass can reduce plant performance by 50% or more. Do not forget to carry out regular cleaning, and a do-it-yourself installation will repay you with kilowatts of completely free, and most importantly, environmentally friendly energy.

Video: do-it-yourself solar panel assembly

Today, there are no barriers to assembling a solar panel with your own hands. There are no problems either with the purchase of photocells, or with the purchase of a controller or energy converter. We hope that this article will be your starting point on the path to an autonomous home, and you will finally get down to business. We will be waiting for your questions, ideas and suggestions regarding the design and improvement of solar panels. See you soon!

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