Solar battery production: technology and equipment. DIY solar panels DIY solar panels from improvised

10.05.2020

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 collect 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 generation direct current. 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 alternative source energy best suited the first two types of plates.

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 electricity with a voltage of 0.5 V. The best option is SB with a nominal voltage of 18 V. Based on this, the required number of photocells for the device is calculated.

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. When using a 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 a 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 KT or P type. Inside them is a fairly 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. Output voltage 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. Homemade solar battery, made according to 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 top edge of the electrodes. To prepare a mixture, 2–4 tablespoons of salt (depending on the volume of the bottle) are dissolved in a small amount 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.

Selection of components for manufacturing

To reduce the cost of a solar station, you need to try to assemble it yourself. To do this, you will need to purchase the necessary components, some elements can be made by yourself.

It will be possible to independently collect:

frames with photoelectric converters;
charge controller;
voltage inverter;

The largest costs will be associated with the acquisition of the solar cells themselves. Parts can be ordered from China or on eBay, this option will cost less.

It is prudent to purchase serviceable converters with damage and defects - they are simply rejected by the manufacturer, but they are quite serviceable. You cannot buy elements of different sizes and power - the maximum current of the solar battery will be limited by the current of the smallest element.

To make a frame with solar cells you will need:

aluminum profile;
solar cells (usually 36 pieces for one frame);
solder and flux;
drill;
fasteners did;
silicone sealant;
copper bus;
a sheet of transparent material (plexiglass, polycarbonate, plexiglass);
a sheet of plywood or textolite (plexiglass);
Schottky diodes;

It makes sense to assemble the inverter yourself only with low power consumption. A simple charge controller is not so expensive, so no special meaning spend time making the device.

DIY manufacturing technology

To assemble solar panels you will need:

Design a frame (case).
Solder all the solar cells in a parallel circuit.
Fix the solar cells to the frame.
Make the housing airtight - direct contact with atmospheric precipitation on photovoltaic cells is unacceptable.
Locate the battery in an area with the highest amount of sunlight.

To meet the energy needs of a private house, one solar panel (frame) will not be enough. Based on practice, from one square meter solar panel can get 120W of power. For the normal energy supply of a residential building, it will take about 20 square meters. m. area of solar cells.

Most often, batteries are placed on the roof of the house on the sunny side.

Case assembly

The body can be assembled from plywood sheet and slats, or from aluminum corners and sheet and plexiglass (textolite). It is necessary to decide how many elements will be placed in the frame. It should be borne in mind that a gap of 3-5 mm is required between the elements, and the size of the frame is calculated taking into account these distances. The distance is necessary so that during thermal expansion the plates do not touch each other.

Assembling a structure from aluminum profile and plexiglass:

a rectangular frame is made from an aluminum corner;
Holes for fasteners are drilled in the corners in the aluminum case;
silicone sealant is applied to the inside of the body profile around the entire perimeter;
a sheet of plexiglass (textolite) is installed in the frame and tightly pressed against the frame;
at the corners of the case, with the help of screws, fixing corners are placed, which securely fix the sheet of transparent material in the case;
the sealant is allowed to dry thoroughly;

Everything, the body is ready. Before placing the solar cells in the housing, it is necessary to thoroughly wipe the surface from dirt and dust.

Photocell connection

When handling photoelectronic elements, it should be remembered that they are very fragile and require careful handling. Before connecting the plates in a serial chain, they are first carefully but gently wiped - the plates must be perfectly clean.

If the photocells were purchased already with soldered conductors, this simplifies the process of connecting the modules. But before assembly, in this case, it is necessary to check the quality of the finished soldering, and if there are irregularities, eliminate them.

On the photovoltaic plates, there are contacts on both sides - these are contacts of different polarity. If the conductors (buses) have not yet been soldered, you must first solder them to the contacts of the plates, and then connect the photovoltaic cells to each other.

To solder busbars to photovoltaic modules, you need:

Measure the desired length of the tire and cut into pieces the desired number of strips.
Wipe the contacts of the plates with alcohol.
Apply a thin layer of flux to the contact along the entire length of the contact on one side.
Attach the tire exactly along the length of the contact and slowly draw a heated soldering iron over the entire soldering surface.
Turn the plate over and repeat all soldering operations on the other side.

You can not strongly press the soldering iron to the plate, the element may burst. It is also necessary to check the quality of the soldering - there should be no irregularities on the front side of the photocells. If the bumps and roughness remain, you need to carefully walk the soldering iron along the contact seam again. It is necessary to use a low-power soldering iron.

What needs to be done in order to correctly and accurately connect photovoltaic cells:

If there is no experience in assembling elements, it is recommended to use a marking surface on which elements should be placed (plywood sheet).
Arrange solar panels strictly according to the markup. When marking, do not forget to leave a distance of 5 mm between the elements.
When soldering the contacts of the plates, be sure to monitor the polarity. The photocells must be properly connected in series, otherwise the battery will not work properly.

Mechanical installation of panels:

In the case, make markings for the plates.
Place the solar cells in the housing, placing them on the plexiglass. In the frame, fix with silicone glue in the marked places. Do not apply much glue, just a tiny drop in the center of the plate. Press carefully so as not to damage the plates. It is better to move the plates together into the case, it will be inconvenient for one.
Connect all wires at the edges of the plates with common busbars.

Before sealing the panel, you need to test the quality of the soldering. The structure is carefully taken out closer to the sunlight and the voltage on the common tires is measured. It should be within the expected values.

Alternatively, sealing can be done as follows:

Apply droplets silicone sealant between plates and along the edges of the case, gently press the edges of the photocells against the plexiglass with your fingers. It is necessary that the elements lie as close as possible to the transparent base.
Put a small weight on all edges of the elements, say, heads from an automotive tool kit.
Let the sealant dry well., the plates will be securely fixed during this time.
Then carefully grease all the joints between the plates and the edges of the frame. That is, you need to lubricate everything in the case, except for the plates themselves. Sealant getting on the edges of the back side of the plates is acceptable.

Final assembly of the solar panel

Install the connector on the side of the case, connector connect with Schottky.
Close the outer side of the plate with a protective screen from transparent material. In this case, Plexiglas. The design must be airtight and prevent the penetration of moisture into it.
The front side (plexiglass) is desirable to process, for example, varnish (lacquer PLASTIK-71).

What is a Schottky diode for? If the light falls only on part of the solar panel, and the other part is darkened, the elements may fail.

Diodes help to avoid structural failure in such cases. In this case, power is lost by 25%, but diodes cannot be dispensed with - they shunt the current, the current bypasses the photocells. To minimize the voltage drop, it is necessary to use low-resistance semiconductors, such as Schottky diodes.

Advantages and disadvantages of a solar battery

Solar panels have both advantages and disadvantages. If there were only one pluses from the use of photoelectric converters, the whole world would have switched to this type of electricity generation long ago.

Advantages:

Autonomy of the power supply, there is no dependence on power outages in the centralized power grid.
No subscription fee for the use of electricity.

Flaws:

High cost equipment and elements.
Dependence on sunlight.
Possibility of damage to elements solar battery due to adverse weather conditions (hail, storm, hurricane).

In what cases it is advisable to use the installation on photovoltaic cells:

If the object (house or cottage) is located at a great distance from the power line. It could be country cottage in the rural hinterland.
When the object is located in the south sunny area.
When combined various kinds energy. For example, heating a private house using stove heating and solar energy. The cost of a low-power solar station will not be so high, and can be economically justified in this case.

Installation

It is necessary to mount the battery in the place of maximum illumination by sunlight. The panels can be mounted on the roof of the house, on a rigid or swivel bracket.

The front of the solar panel should face south or southwest at an angle of 40 to 60 degrees. When installing, take into account external factors. Panels should not be obstructed by trees and other objects, dirt should not get on them.

It is better to buy photocells with small defects. They are also workable, only they have a not so beautiful appearance. New elements are very expensive, the assembly of a solar battery will not be economically justified. If there is no particular hurry, it is better to order plates on eBay, it will cost even less. With shipment and China, you need to be more careful - there is a high probability of receiving defective parts.
Photocells need to be bought with a small margin, there is a high probability of their breakdown during installation, especially if there is no experience in assembling such structures.
If the elements are not yet used, you should hide them in a safe place to avoid breakage of fragile parts. You can not stack the plates in large stacks - they can burst.
At the first assembly, a template should be made, which will mark the location of the plates before assembly. This makes it easier to measure the distance between elements before soldering.
Soldering is necessary with a low-power soldering iron, and in no case apply force when soldering.
It is more convenient to use aluminum corners to assemble the case, wooden structure less reliable. As a sheet on the back of the elements, it is better to use plexiglass or other similar material and is more reliable than painted plywood and looks aesthetically pleasing.
Photovoltaic panels should be located in places where sunlight will be maximum. throughout the daylight hours.

House power supply scheme

The series power supply chain of a private solar-powered house is as follows:

Multi-panel solar array, which are located on the slope of the roof of the house, or on the bracket. Depending on the energy consumption, there can be up to 20 panels or more. The battery generates a direct current of 12 volts.
Charge controller. The device protects batteries from premature discharge, and also limits the voltage in the DC circuit. Thus, the controller protects the batteries from overload.
voltage inverter. Converts direct current to alternating current, thereby enabling the consumption of electricity by household appliances.
Batteries. For private houses and cottages, several batteries are installed, connecting them in series. They serve to store energy. The energy of the batteries is used at night, when the solar cells do not produce current.
electric meter.

Quite often, in private homes, the power supply system is supplemented by a backup generator.

In general, it is not so difficult to assemble a solar battery with your own hands. Only certain means, patience and accuracy are needed.

The energy potential of sunlight is huge - its influence can be estimated only because there is a violent life on the planet, which led to the emergence of an intelligent person who actively consumes and processes energy. For billions of years, part of the sun's energy has been accumulated in the deposits of dead organisms (minerals), which are in a form that is relatively easily accessible for extraction and processing.

But pollution environment and the limited supply of the bowels of the earth make mankind take a fresh look at the possibilities of direct use of the energy of sunlight.

To meet the current needs of humanity in energy, it would be enough to fill a relatively small area in the Sahara desert with solar power plants. Since electricity is the most convenient form of energy to use and process, the direct conversion of the sun's light into electricity using solar panels from photovoltaic cells.

The red squares show the area required to accommodate solar power plants in order to meet the energy needs of the Earth, Europe and Germany, respectively.

The principle of operation of photocells

A photocell is a device that converts the energy of light photons into electricity. Currently, promising technologies for creating semiconductor photoelectric converters based on internal photoelectric effect. With the internal photoelectric effect, electrons are redistributed according to their energy state in semiconductors under the influence of radiation.

Illustration and description of the internal photoelectric effect

The conversion of light energy into electricity occurs in inhomogeneous semiconductor structures. Heterogeneity of structures is created by doping, joining, and changing chemical composition semiconductors. Thus, there is a gradient of change in the band gap of the semiconductor under the influence of radiation, which leads to the emergence of an electromotive force.

Description of the application of the photoelectric effect

The efficiency of a photocell depends on the following factors:

photoconductivity of semiconductors;
scattering and reflection of projected light;
passing part of the radiation through the photoelectric converter without conversion;
recombination of the resulting photoelectron pairs;
internal resistance of the photocell;
other physical and chemical characteristics.

Basic laws of the photoelectric effect

Radio amateurs know that if you cut a diode or a transistor and illuminate a semiconductor junction, you can get a small potential at the terminals of the element. This effect is often used to create self-made photosensitive sensors or demonstration aids, but this method is unprofitable for large-scale conversion of light into energy.

It is obvious that it is not possible to make a solar battery at home “from scratch” due to the technological complexity of the process, therefore, for an ordinary consumer, it makes sense to create generating panels from ready-made photovoltaic cells with his own hands.

Ready-made photovoltaic cells for solar panels in protective transport packaging

Photocell efficiency

The effective band gap of a semiconductor junction depends on the wavelength (luminescence spectrum). Therefore, cascade technologies began to be used in laboratory and industrial photocells, which make it possible to separate light into spectra and separately irradiate photoelectronic converters designed for a narrow range of light waves.

These technologies involve the use of knowledge in various industries science with the use of complex research in laboratories. For the manufacture of photocells, silicon wafers with impurities of various chemical elements and compounds are used. The lucrative prospects for converting solar energy into electricity have allowed the development of an entire industry, comparable in power to the production of radio electronics.

Manufacturers of photocells are engaged in improving the optical and electrical properties of photocells by coating, creating anti-reflective coatings, and using a multi-stage structure.

At the moment, the average efficiency of industrial conversion of light into electricity (efficiency) is about 14%, and for the best samples about 25%. In laboratory conditions, an efficiency of about 45% has been achieved.

Formation of a generating battery

The working principle of solar panels is connection of photocells into one structure that generates electricity, which is accumulated in batteries, with subsequent processing into electricity of industrial voltage and frequency.

Photocells, like other batteries, when connected in series, give more voltage, and when connected in parallel, the output current increases and the total internal resistance of the battery decreases.

This principle of forming a solar battery is scalable, that is, it is applicable both for connecting individual photocells and for connecting already assembled assemblies into one panel.

Since the dimensions of semiconductor junctions are measured in microns, manufacturers combine photoelectronic converters in ready-made photocells that have output characteristics (voltage, current, power) and are suitable for further combination in a battery.

Before you make a solar panel with your own hands, you need to know the expected output power, which is calculated from the charging current of the batteries that are connected to inverters to generate mains voltage. Thus, knowing the maximum charging current of available batteries, it is possible to calculate the number and area of required photocells for a solar battery, taking into account their efficiency.

Accessories for solar battery

As can be seen from the figure below, the world leaders in the production of photovoltaic cells for solar batteries of various capacities are China and Germany. Therefore, in most cases, large manufacturers of solar power plants and individual users place orders via the Internet, purchasing Chinese photovoltaic cells to assemble generating panels.

Dynamics of growth in the production of photovoltaic cells for converting solar energy into electricity

Because the photocell plate is very fragile, a strong structure is needed to protect the photocell from bending and environmental influences. This design should provide:

reliable electrical connection photocells;
strength and invariance of the geometric parameters of the assembly;
protection against mechanical damage;
protection against moisture, precipitation, dust and dirt;
low light reflection (anti-reflective coating);
good transparency of the protective glass.

The latest technology allow you to make solar panels flexible, which significantly reduces the problems during their installation

Manufacturers offer photocells of various sizes and types, which have their own assembly, installation and connection nuances. Also often attached film anti-glare coatings that the master will have to apply himself to the assembled solar panel. Therefore, you need to carefully study all available documentation for purchased solar cells before assembling solar panels. The video below shows an overview of the most popular photocells.

Getting electricity from a solar battery

It must be remembered that the output current and voltage of the solar battery depends on the density of the light flux and the angle of incidence of the sun's rays. Therefore, in cloudy weather, as well as in the morning and evening, the output power of the battery will be several times lower than at sunny noon.

Since weather conditions cannot be changed, it is possible to increase the total number of rays directed at the solar battery using reflectors made from foil.

Using homemade foil reflectors, you can significantly increase the efficiency of solar panels

As a rule, solar panels are installed perpendicular to a hypothetical line from the Sun, which is in the sky at noon. In other words, a perpendicular placed on the area of the solar panel should not cast a shadow. This installation angle will change according to the change of seasons - on the day of the summer solstice, the Sun rises above the horizon at its highest point.

In most cases, solar panels are installed permanently and without adjustment, sometimes even on different sides of the roof of the house, receiving efficient generation of electricity only at certain hours of the day.

To maximize the efficiency of the solar panel, you need to install a device that will track the movement of the Sun across the sky, directing the panel perpendicular to the incident rays.

The solar battery is installed on a rotary device that tracks the movement of the Sun during daylight hours.

Solar batteries must have charge controller to maintain the correct charging current parameters. Observing the charging current in the most favorable period, noting the required time, it is possible to plan an increase in the area of solar panels or the installation of additional batteries.

With the simplest connection of solar panels to the battery, it is recommended to connect a diode in series between them to prevent reverse current discharge.

AT modern world it is difficult to imagine existence without electrical energy. Lighting, heating, communication and other pleasures comfortable life are directly dependent on it. This forces us to look for alternative and independent sources, one of which is the sun. This area of energy is not yet too developed, and industrial plants are not cheap. The output will be the manufacture of solar panels with their own hands.

What is a solar battery

The solar battery is a panel consisting of interconnected photocells. It directly converts solar energy into electrical current. Depending on the design of the system, electrical energy is accumulated or immediately goes to the energy supply of buildings, mechanisms and devices.

A solar battery is made up of interconnected photovoltaic cells.

Almost everyone used the simplest photocells. They are built into calculators, flashlights, batteries for recharging electronic gadgets, garden lanterns. But the use is not limited to this. There are solar-powered electric vehicles; in space, this is one of the main sources of energy.

In countries with a lot of sunny days, batteries are installed on rooftops and used for heating and hot water. This type is called collectors, they convert the energy of the sun into heat.

Often, the power supply of entire cities and towns occurs only due to this type of energy. Solar power plants are being built. They are especially popular in the USA, Japan and Germany.

Device

The device of the solar battery is based on the phenomenon of the photoelectric effect, discovered in the twentieth century by A. Einstein. It turned out that in some substances, under the action of sunlight or other substances, charged particles are detached. This discovery led in 1953 to the creation of the first solar module.

The material for the manufacture of elements are semiconductors - combined plates of two materials with different conductivity. Most often, polycrystalline or monocrystalline silicon with various additives is used for their manufacture.

Under the action of sunlight, an excess of electrons appears in one layer, and their deficiency in the other. "Extra" electrons go into the region with their deficiency, this process has received district name transition.

The solar cell consists of two semiconductor layers with different conductivity

Between the materials that form an excess and a shortage of electrons, a barrier layer is placed that prevents the transition. This is necessary so that the current occurs only when there is a source of energy consumption.

Light photons hitting the surface knock out electrons and supply them with the necessary energy to overcome the barrier layer. Negative electrons pass from the p-conductor to the n-conductor, and positive electrons make the opposite path.

Due to the different conductivity of semiconductor materials, it is possible to create a directed movement of electrons. Thus, an electric current is generated.

The elements are connected in series with each other, forming a panel of a larger or smaller area, which is called a battery. Such batteries can be directly connected to the source of consumption. But since solar Activity during the day it changes, and at night it stops altogether, they use batteries that accumulate energy during the absence of sunlight.

A necessary component in this case is the controller. It serves to control the charging of the battery and turns off the battery when fully charged.

The current generated by the solar battery is constant, to use it must be converted to alternating current. This is what an inverter is for.

Since everything electrical devices, consuming energy, are designed for a certain voltage, the system needs a stabilizer that provides the desired values.

Additional devices are installed between the solar module and the consumer

Only if all these components are present, it is possible to obtain a functional system that supplies energy to consumers and does not threaten to disable them.

Types of elements for modules

There are three main types of solar panels: polycrystalline, monocrystalline and thin film. Most often, all three types are made from silicon with various additives. Cadmium telluride and copper-cadmium selenide are also used, especially for the production of film panels. These additives contribute to an increase in cell efficiency by 5-10%.

crystalline

The most popular are monocrystalline. They are made of single crystals, have a uniform structure. Such plates have the shape of a polygon or a rectangle with cut corners.

The single-crystal cell has the shape of a rectangle with beveled corners.

The battery, assembled from single-crystal elements, has a higher productivity compared to other types, its efficiency is 13%. It is light and compact, not afraid of slight bending, can be installed on uneven ground, service life of 30 years.

The disadvantages include a significant decrease in power during cloudiness, up to a complete cessation of energy generation. The same happens when it gets dark, the battery will not work at night.

The polycrystalline cell has a rectangular shape, which allows you to assemble the panel without gaps

Polycrystalline are produced by casting, have a rectangular or square shape and a heterogeneous structure. Their efficiency is lower than single-crystal ones, the efficiency is only 7-9%, but the drop in output in cloudy, dusty or at dusk is not significant.

Therefore, they are used in the construction of street lighting, but they are more often used by homemade ones. The cost of such plates is lower than single crystals, the service life is 20 years.

Film

Thin-film or flexible elements are made from an amorphous form of silicon. The flexibility of the panels makes them mobile, rolled up, you can take them with you on trips and have an independent power source anywhere. The same property allows you to mount them on curved surfaces.

The film battery is made of amorphous silicon

In terms of efficiency, film panels are twice as inferior to crystalline ones; to produce the same amount, a double battery area is required. And the film does not differ in durability - in the first 2 years, their efficiency drops by 20-40%.

But when cloudy or dark, energy production is reduced by only 10-15%. Their relative cheapness can be considered an undoubted advantage.

What can you make a solar panel at home

Despite all the advantages of commercially produced batteries, their main disadvantage is their high price. This trouble can be avoided by making the simplest panel with their own hands from improvised materials.

From diodes

A diode is a crystal in a plastic case that acts as a lens. It concentrates the sun's rays on the conductor, resulting in an electric current. Connecting each other a large number of diodes, we get a solar battery. Cardboard can be used as a board.

The problem is that the power of the received energy is small, to generate a sufficient amount, a huge number of diodes will be needed. In terms of financial and labor costs, such a battery is much superior to the factory one, and in terms of power it is much inferior to it.

In addition, production drops sharply with a decrease in illumination. Yes, and the diodes themselves behave incorrectly - spontaneous glow often occurs. That is, the diodes themselves consume the generated energy. The conclusion suggests itself: inefficient.

From transistors

As in diodes, the main element of the transistor is a crystal. But it is enclosed in a metal case that does not let in sunlight. To make a battery, the case cover is sawn off with a hacksaw.

A low power battery can be assembled from transistors

Then the elements are attached to a plate of textolite or other material suitable for the role of the board, and interconnected. In this way, you can assemble a battery, the energy of which is enough to operate a flashlight or radio, but you should not expect much power from such a device.

But as camp source low power energy is quite suitable. Especially if you are fascinated by the process of creation itself and the practical benefits of the result are not very important.

Craftsmen suggest using CDs and even copper plates as photocells. Portable phone charger is easy to make from photocells from garden lanterns.

The best solution would be to buy ready-made plates. Some online sites sell modules with a small manufacturing defect at an affordable price, they are quite suitable for use.

Rational placement of batteries

The placement of the modules largely determines how much power the system will produce. The more rays hit the photocells, the more energy they will produce. For an optimal location, the following conditions must be met:

Important! The current strength of a battery is determined by the performance of the weakest cell. Even a small shadow on one module can reduce system performance by 10 to 50%.

How to calculate the required power

Before proceeding with the assembly of the battery, it is necessary to determine the required power. This depends on the number of cells purchased and total area finished batteries.

The system can be either autonomous (providing electricity to the house on its own) or combined, combining the energy of the sun and a traditional source.

The calculation consists of three steps:

Find out the total power consumption.
Determine the sufficient battery capacity and inverter capacity.
Calculate the required number of cells based on the insolation data in your area.

Power consumption

For an autonomous system, you can determine it by your electric meter. Divide the total amount of energy consumed per month by the number of days to get the average daily consumption.

If only a part of the devices will be powered by the battery, find out their power according to the passport or marking on the device. Multiply the resulting values by the number of hours of work per day. Adding the obtained values for all devices, get the average consumption per day.

AB (battery) capacity and inverter power

AB for solar systems must withstand a large number of discharge and discharge cycles, have a small self-discharge, withstand a large charging current, work at high and low temperatures while requiring minimal maintenance. These parameters are optimal for lead-acid batteries.

Another important indicator is capacity, the maximum charge that a battery can accept and store. Insufficient capacity is increased by connecting batteries in parallel, in series, or by combining both connections.

Calculation will help to find out the required number of ABs. Consider it for the concentration of energy reserves for 1 day in a battery with a capacity of 200 Ah and a voltage of 12 V.

Assume daily demand is 4800Vh, system output voltage is 24V. Assuming inverter loss is 20%, enter a correction factor of 1.2.

4800:24х1.2=240 Ah

The depth of discharge of AB should not exceed 30-40%, we will take this into account.

240х0.4= 600 Ah

The resulting value is three times the capacity of the battery, so 3 batteries connected in parallel will be required to supply the required amount. But at the same time, the battery voltage is 12 V, in order to double it, you will need 3 more batteries connected in series.

To obtain a voltage of 48 V, connect in parallel two parallel chains of 4 ABs

The inverter is used to convert direct current into alternating current. Choose it by peak, maximum load. On some consumer devices, the starting current is much higher than the nominal one. It is this indicator that is taken into account. In other cases, nominal values are taken into account.

The form of tension also matters. The best option is a pure sine wave. Suitable for devices that are insensitive to voltage drops square shape. It should also take into account the possibility of switching the device from AB directly to solar panels.

Required number of cells

Insolation indicators in different areas are very different. For a correct calculation, you need to know these numbers for your area, the data is easy to find on the Internet or at a weather station.

Monthly insolation table for different regions

Insolation depends not only on the time of year, but also on the angle of the battery

When calculating, be guided by the indicators of the least insolation during the year, otherwise the battery will not produce enough energy during this period.

Let's assume that the minimum indicators - in January, 0.69, the maximum - in July, 5.09.

Correction coefficient for winter time - 0.7, for summer time - 0.5.

Required amount of energy - 4800 Wh.

One panel has a power of 260 W and a voltage of 24 V.

Losses on AB and inverter are 20%.

We calculate consumption taking into account losses: 4800 × 1.2 = 5760 Wh = 5.76 kWh.

We determine the performance of one panel.

Summer: 0.5×260×5.09= 661.7 Wh.

Winter: 0.7×260×0.69=125.5Wh.

We calculate the required number of batteries by dividing the energy consumed by the performance of the panels.

Summer: 5760/661.7=8.7 pcs.

In winter: 5760/125.5=45.8 pcs.

It turns out that for full provision, five times more modules will be needed in winter than in summer. Therefore, it is worth immediately installing more batteries or winter period provide a hybrid power supply system.

How to assemble a solar battery with your own hands

The assembly consists of several stages: the manufacture of the case, the soldering of the elements, the assembly of the system and its installation. Before you get started, stock up on everything you need.

The battery is made up of several layers.

Materials and tools

photocells;
flat conductors;
alcohol-rosin flux;
soldering iron;
aluminum profile;
aluminum corners;
hardware;
silicone sealant;
hacksaw for metal;
screwdriver;
glass, plexiglass or plexiglass;
diodes;
measuring devices.

It is better to order photocells complete with conductors, they are specially designed for this purpose. Other conductors are more brittle, which can be a problem when soldering and assembling. There are cells with already soldered conductors. They cost more, but save a lot of time and labor.

Purchase plates with conductors, this will reduce the operating time

The body frame is usually made of an aluminum angle, but it is possible to use wooden slats or bars of square section 2x2. This option is less preferred as it does not provide sufficient weather protection.

For a transparent panel, choose a material with a minimum refractive index of light. Any obstacle in the path of the rays increases the energy loss. It is desirable that the material transmits as little infrared radiation as possible.

Important! The more the panel heats up, the less power it generates.

Frame calculation

The dimensions of the frame are calculated based on the size of the cells. It is important to provide a small distance of 3-5 mm between adjacent elements and take into account the width of the frame so that it does not overlap the edges of the elements.

The cells are produced in various sizes, consider the option of 36 plates, 81x150 mm in size. We arrange the elements in 4 rows, 9 pieces in one. Based on these data, the dimensions of the frame are 835x690 mm.

Box manufacturing

Soldering elements and assembling modules

If the elements are purchased without contacts, they must first be soldered to each plate. To do this, cut the conductor into equal segments.

Cut out a rectangle of the desired size from cardboard and wind the conductor around it, then cut it on both sides.
Apply flux to each conductor, attach a strip to the element.
Carefully solder the conductor along the entire length of the cell.
Solder the conductors to each plate
Lay the cells in a row one after another with a gap of 3-5 mm and sequentially solder together.
During installation, periodically check the functionality of the modules
Transfer the finished rows of 9 cells into the body and align with each other and the outline of the frame.
Solder in parallel, using wider tires and observing the polarity.
Lay rows of elements on a transparent substrate and solder together
Bring out the contacts "+" and "-".
Apply 4 drops of sealant to each element and lay the second glass on top.
Let the glue dry.
Fill around the perimeter with sealant so that moisture does not get inside.
Fasten the panel to the housing using the corners, screwing them into the sides of the aluminum profile.
Install a Schottke blocking diode with sealant to prevent battery discharge through the module.
Provide the output wire with a two-pin connector, then connect the controller to it.
Screw the corners to the frame to secure the battery to the support.

Video: soldering and assembling the solar module

The battery is ready, it remains to install it. For more efficient work, you can make a tracker.

Production of a rotary mechanism

The simplest rotary mechanism is easy to make yourself. The principle of its operation is based on a system of counterweights.

From wooden blocks or an aluminum profile, assemble a support for the battery in the form of a stepladder.
Using two bearings and a metal rod or pipe, mount the battery on top so that it is fixed in the center of the larger side.
Orient the structure from east to west and wait until the sun is at its zenith.
Rotate the panel so that the rays hit it vertically.
Fix a container of water at one end, balance it at the other end with a weight.
Make a hole in the container so that the water flows out little by little.

As the water flows out, the weight of the vessel will decrease and the edge of the panel will rise up, turning the battery towards the sun. The size of the hole will have to be determined empirically.

The simplest solar tracker is made on the principle of a water clock

All you need is to pour water into a container in the morning. You cannot install such a structure on the roof, but for garden plot or front lawns, it will do just fine. There are other, more complex tracker designs, but they will cost more.

Video: how to make your own electronic solar tracker

Battery installation

Now you can test and enjoy free electricity.

Module maintenance

Solar panels do not require special maintenance, because they have no moving parts. For their normal functioning it is enough from time to time to clean the surface from dirt, dust and bird droppings.

Wash the batteries with a garden hose, with good water pressure, you don’t even need to climb onto the roof for this. Check the condition of the additional equipment.

How soon will the costs pay off

You should not expect momentary benefits from the solar power supply system. Its average payback is approximately 10 years for an autonomous system at home.

The more energy you consume, the faster your costs will pay off. After all, for both small and large consumption, the purchase of additional equipment is required: a battery, an inverter, a controller, and they leave a small part of the costs.

Consider also the life of the equipment, and the life of the panels themselves, so that you do not have to change them before they pay off.

Despite all the costs and disadvantages, solar energy is the future. The sun is a renewable energy source and will last at least another 5,000 years. Yes, and science does not stand still, new materials for photocells appear, with a much higher efficiency. So, soon they will be more affordable. But you can use the energy of the sun already now.