A solar battery is a device that allows you to generate electricity using special photocells. It helps to significantly reduce electricity costs and obtain an inexhaustible source of electricity. Such an installation can not only be purchased at finished form, but also do it yourself. A solar panel for a home in the private sector will become ideal solution, which will help avoid frequent power outages.
General information
Before making a solar battery at home, you need to study in detail its structure, operating principle, advantages and disadvantages. Having this information, you can correctly select the necessary components that will work for a long time and be beneficial.
Design and principle of operation
Designs of all types work by converting energy emitted by a nearby star into electrical energy. This happens thanks to special photocells that are combined into an array and form general design. Semiconductor elements made from silicon are used as energy converters.
Operating principle of solar panel:
- Light coming from the Sun hits photocells.
- It knocks out free electrons from the last orbits of all silicon atoms.
- Because of this it appears a large number of free electrons that begin to move quickly and chaotically between the electrodes.
- The consequence of this process is the generation of direct current.
- It is then quickly converted to variable and sent to the receiving device.
- It distributes the received electricity throughout the house.
Advantages and disadvantages
DIY solar panels have a number of advantages over factory designs and other energy sources. Thanks to this, the devices are quickly gaining popularity and are used all over the world.
Among positive aspects solar panels the following should be highlighted:
Despite the many advantages, solar panels also have disadvantages. They must be taken into account before starting the manufacture of the structure and its installation.
The disadvantages include the following:
In order for the finished structure to perform its functions efficiently and provide people with a sufficient amount of electricity, it is necessary to manufacture it correctly. To do this, you need to take into account many factors and choose only high-quality materials.
Primary requirements
Before making a solar battery with your own hands, you need to complete a number of preparatory measures and carefully study all the requirements for the device. This will help to get a working installation and simplify the installation process.
To ensure that the solar panel operates at its maximum potential, the following requirements must be met:
Materials and tools
Photocells are considered the most important parts of the device. Manufacturers offer customers only 2 varieties: monocrystalline (efficiency up to 13%) and polycrystalline silicon (efficiency up to 9%).
The first option is only suitable for working in sunny weather, and the second - in any weather. Others important elements structures are conductors. They are used to connect photocells to each other.
For making a panel You will need the following materials and tools:
Procedure
In order to make solar panels with your own hands at home, you must follow the sequence of actions. Only in this case can mistakes be avoided and the desired result achieved.
The panel manufacturing process is simple and consists of the following steps:
- A set of poly- or monocrystalline solar cells is taken and the parts are assembled into a common structure. Their number is determined based on the requirements of the home owners.
- Contours formed from tin soldered conductors are applied to the photocells. This operation is performed on a flat glass surface using a soldering iron.
- According to a pre-prepared electrical circuit, all cells are connected to each other. In this case, it is necessary to connect shunt diodes. Ideal option For the solar battery, Schottky diodes will be used to prevent the panel from discharging at night.
- The cell structure moves to open space and tested for functionality. If there are no problems, you can begin assembling the frame.
- For these purposes, special aluminum corners are used, which are attached to the body elements using hardware.
- A thin layer is applied to the internal parts of the slats and evenly distributed. silicone sealant.
- A sheet of plexiglass or polycarbonate is placed on top of it and pressed tightly against the contour of the frame.
- The structure is left for several hours for the silicone sealant to dry completely.
- Once this process is completed, transparent sheet additionally attached to the body using hardware.
- Selected photocells with conductors are placed along the entire inner part of the resulting surface. In this case, it is important to leave a small distance (about 5 millimeters) between adjacent cells. To simplify this procedure, you can apply the necessary markings in advance.
- The installed cells are securely fixed to the frame using mounting silicone, and the panel is completely sealed. All this will help increase the life of the solar battery.
- The product is left to dry the applied mixture and acquires its final appearance.
Products from scrap materials
A solar battery can be assembled not only from expensive materials, but also from improvised materials. The finished design, although it will be less efficient, will allow you to save a little on electricity.
This is one of the simplest and available options making a homemade solar panel. The device will be based on low-voltage diodes, which are made in a glass case.
The battery is made following the following sequence of actions:
Copper foil
If you need to get a small amount of electricity, you can make a solar battery from ordinary foil.
The finished structure will have low power, so it can only be used to recharge small devices.
Step-by-step instruction:
Beer cans
This simple method of making a battery does not require large financial costs. With its help, you can get a small amount of electricity, which will slightly reduce costs.
Procedure:
A self-made solar panel is a wonderful device that can reduce energy costs. If it is manufactured correctly and all recommendations are followed, you can make a high-quality product that will work for many years.
We continue our topic on the construction of a home solar power plant. WITH general information You can learn about the principles of calculating solar panels, as well as for autonomous power supply systems, by reading our previous articles. Today we will talk about the features of self-manufacturing solar panels, the sequence of connecting electrical converters and protective devices, which should be included in the solar power plant kit.
Manufacturing of photovoltaic modules
A standard photovoltaic module (panel) consists of three main elements.
- Panel body.
- Frame.
- Photovoltaic cells.
The simplest design element of a solar module is its housing. As a rule, its front side is an ordinary sheet of glass, the dimensions of which correspond to the number of solar cells.
Adoronkin User FORUMHOUSE
The glass I used was regular window glass – 3 mm (the most inexpensive). I conducted a test: glass degrades the performance of the module slightly, so I don’t see much point in using tempered or coated glass.
Window glass is often used to make protective housing for solar panels. If you doubt the strength of this material, then you can use tempered or regular glass, but thicker (5...6 mm). In this case, there is no doubt that the photovoltaic elements will be reliably protected from destructive natural disasters (from hail, for example).
The back side of the case can be made of moisture-resistant material, which will protect it from dust and moisture getting on the solar cells. This can be metal sheet, hermetically attached to the frame with rivets and silicone, or, again, ordinary glass.
At the same time, the presence back wall on the body of a homemade solar panel, some craftsmen do not welcome it at all.
Adoronkin
The back of the battery is open (for better cooling), but covered with acrylic varnish mixed with a transparent sealant.
Considering that when the panels heat up, their power drops significantly, such a solution seems justified. After all, it provides effective cooling of semiconductor elements and at the same time high-quality sealing of solar cells. All together is guaranteed to extend the life of solar panels.
Frame
Frames for homemade solar panels are most often made from standard aluminum angles. It is better to use coated aluminum - anodized or painted. If you are tempted to make a frame from wood or plastic, be prepared for the fact that after a couple of years the product may dry out or even fall apart under the influence of climatic factors (with the exception of window plastic).
BOB691774 User FORUMHOUSE
I buy from where the windows are made. Price – 80 rub. per meter The profile is completely ready for work, you just need to cut it at 45° and under heat, glue the corners.
Let's consider the simplest panel option: a panel with an aluminum frame.
The aluminum frame parts are easily fastened together with bolts or self-tapping screws.
Subsequently, the aluminum corner can be special effort glue the glass body. All you need for this is regular silicone sealant.
Adoronkin
I took silicone sealant - universal. 1 tube is enough. It is better to take transparent sealant. The chemical safety of the sealant in relation to photovoltaic cells was confirmed by the annual operation of the battery.
The result will be a shallow box with a glass bottom, to which photovoltaic cells will subsequently be glued.
When determining the size of the housing and frame, one should take into account the need for a gap between adjacent photovoltaic cells, which is equal to 2...5 mm.
Soldering solar cells
The most critical stage in assembling solar modules is soldering the photovoltaic cells. Solar cells are made of very fragile material, so they require appropriate handling. Those people who have already dealt with them will henceforth, when purchasing solar cells, order cells with a certain quantity reserve (10 - 15%). For example, to make a panel designed for 36 elements, they purchase 39 - 42 cells.
Thin busbars for soldering solar cells, thicker busbars (with the help of which adjacent rows of panels are combined with each other) and solar cells are best purchased from the same seller. This saves time searching for suitable elements and provides certain guarantees of their compatibility.
Soldering of elements in case of their serial connection is carried out according to the following scheme.
The negative (front) contact of the solar cell is soldered to the positive (back) contact of the next cell, and so on.
This is what the finished panel looks like.
For work you will need the following tools and materials:
- Powerful soldering iron 40-60 W (at least).
- Flux (flux marker) must be neutral (otherwise the soldered contacts will quickly oxidize).
- Tires of different widths.
- Rubber gloves - to avoid smearing the solar cells (especially their front part).
We also need tin. This is in case the busbar is poorly soldered to the contacts. The cells being worked with are located on a hard and flat surface. It could be a board or glass. To prevent the cells from sliding on the working surface of the table, they can be fixed using pieces of electrical tape glued around the perimeter of the element. You should not put electrical tape on the cell itself (especially on its front part). The free end of the shank should be attached to the table using double-sided tape.
Soldering of elements and assembly of panels is carried out in the following order: first of all, the contact groove of the plate along its entire length is coated with flux. Then the flat busbar is placed in the groove and soldered to the contact of the plate along its entire width (at the negative pole of the element).
Or at three points (usually at the positive pole of the element).
The number of soldering points depends on the element design.
The contacts are soldered to all solar cells one by one. Additional solder is used only in cases where the bar cannot be reliably soldered to the plate the first time.
First of all, the contacts are soldered to the front (negative) side of each cell, which will lie on the glass body of the panel.
A tire of the required size is prepared in advance. Its length should correspond to the width of 2 adjacent plates.
The plates with soldered contacts are laid face down on the glass body of the panel. After this, they can be soldered to each other according to polarity (“–” of each cell is soldered to the “+” of the adjacent cell, and so on).
To make it more convenient to place the elements on the glass body of the panel, its surface can be pre-marked.
Sliderrr User FORUMHOUSE
I marked the location of the cells on the glass with a black felt-tip pen. I positioned the cells and secured them with heads, nuts and bolts.
Nuts, keys and others metal objects in this case they were used as cargo. You can also fix the cells using transparent silicone, which is applied to the glass at the corners of each element.
When connecting adjacent rows of photovoltaic cells, additional solder should be used. This will increase the reliability of soldering at junctions of conductors of different widths.
When all the cells are soldered together, and the conductors are brought out through the aluminum frame of the panel, you can begin to fill the solar cells.
To do this, the seams between adjacent elements are filled with silicone sealant.
Sliderrr
I filled the gaps between the panels with silicone (flattened it a little and cut off the nozzle of the syringe to ensure the aesthetics of the seam and good contact of the silicone with the glass). When it was dry, I coated the perimeter of each panel again. After the sealant had dried, I coated the cells with yacht varnish twice. In the future I will try insulating varnish.
User Mirosh Instead of varnish, he uses white silicone to fill the cells, which he applies to the surface in a thin layer using a spatula. The result is quite satisfactory.
Before final assembly It is advisable to test each element for the power it generates. This can be done using a multimeter. If there are no significant differences between the current and voltage that each individual cell generates, then you can safely include them in the photovoltaic module.
Installation of Schottky diodes
The design of solar panels often uses elements that we have not previously mentioned. These are Schottky diodes.
They are installed for two reasons.
Firstly, shunt diodes are installed so that in the dark or in cloudy weather the solar panels do not discharge the battery included in the solar power plant.
Alex MAP User FORUMHOUSE
In the case of direct connection of solar panels to the battery at night, voltage drops on the panels and they heat up. Therefore, in the circuit of a primitive solar controller, developed 10 years ago, a Schottky diode was introduced (protection against nighttime battery discharge).
If a modern controller is connected to the solar panels, then there is no special need for protection against night discharge. A working controller, without the help of additional devices, will disconnect the power supply from the battery in time.
Secondly, if the solar module is covered by a shadow from standing nearby building (or other massive object), then the power of this element is reduced. The consequences of the power reduction are as follows: in relation to the remaining panels connected in series to the shaded element, the shaded element turns from a current source into a resistive load. The resistance of the shaded module increases greatly, and its temperature increases significantly.
A significant reduction in power is the most harmless thing that can result from partial shading of a series-connected solar battery. After all, eventually the shaded module will overheat and fail. This phenomenon is called the “hot spot effect.”
In order to avoid this effect, a Schottky diode is installed in parallel with each module connected in series (or a series row of solar cells). The diode allows electricity to bypass the shaded panel. In this case, the generated voltage will decrease, but a large current drop will be avoided.
Alex MAP
The large current from the remaining panels of the circuit, which are illuminated, will not be interrupted, but will bypass the shaded parts of the panels through diodes. The final voltage will be slightly lower, but this is not important to the controller. If the panels did not have built-in diodes, then with the slightest shading of even a piece of 1 panel, the entire chain would completely stop producing current.
In other words, power losses will be commensurate with the shading area.
Diodes can be installed parallel to the entire module, or parallel to its individual rows.
Here is a diagram in which each row of cells installed in one module has its own diode. In practice, the module is most often divided into 2 equal parts.
HouseR User FORUMHOUSE
Typically, for a four-row panel, a midpoint is displayed, that is, the cells are bridged in half. The diodes are placed in the terminal box.
In any case, all solar panel modules should be positioned so that the light hits them evenly. Then you won’t have to solve the problem of shunting individual modules or even cells.
For convenience, terminal boxes are located on the back side of the solar panels.
If several series-connected groups of panels are connected to the controller in parallel, then in this case each serial chain is connected to the common circuit through an isolation diode. This allows you to avoid losses due to mismatch of individual serial chains and additionally protect the battery from discharge at night (if, suddenly, the controller fails).
Diodes are selected according to two main parameters: the maximum current that will flow in the forward direction (forward current), and the reverse voltage. The maximum reverse current voltage (Urev.max.) should not lead to diode breakdown. In this case, the performance characteristics of the diode should slightly exceed the panel rating (about 1.3 - 1.5 times).
But there is one trick here.
Max94 User FORUMHOUSE
There are no normal Schottkys for high voltages. These are just poles with a direct current fall. So it's better to take regular ones from Urev. Max ≈ 30...100V.
Installation of panels
How to mount the panels correctly and where to install them? The answers to these questions depend on the design of the security systems and the capabilities of their owner. The only thing that everyone without exception should take care of is maintaining the angle of inclination. For each region this angle will be different, and it depends directly on the latitude of the area.
On average, in winter the angle of inclination should be 10°...15° higher than the optimal value, in summer - by the same amount - lower. can be viewed in the FORUMHOUSE section.
Conductor cross-section
In accordance with the postulates of electrical engineering, too small a conductor cross-section can lead to overheating and even fire. Too large is not bad, but it will lead to an unreasonably inflated increase in the cost of the autonomous system. Therefore, the task of its creator is to find a “golden mean”.
Let's start with the fact that the thickest conductors should be installed in the circuit connecting the battery to the inverter (by the way, the shorter this section is, the better). This is where high currents flow.
The conductors connecting the panels to the inverter, as well as connecting the panels to each other, can be selected with a small cross-section. There may be a relatively high voltage present in these sections of the circuit, but there will always be a low current.
HeliosHouse User FORUMHOUSE
16 mm² is not needed and 10 mm² is not needed. 4 is more than enough. A “thick” wire will only be needed in the inverter circuit; the cross-section must be selected in accordance with the current power.
“Thick” and “thin” are flexible concepts, so let’s not deviate from the standards.
Considering that it is currently prohibited to use aluminum conductors in home power supply systems, the tabular data applies to copper conductors with polyvinyl chloride or rubber insulation.
Also, when choosing conductors, you should pay attention to the recommendations of the manufacturers of inverters, controllers and other devices involved in the system.
Automatic circuit breakers
In the circuit of a solar power plant, as in the circuit of any other powerful source of electricity, it is necessary to install protection against short circuits. First of all, circuit breakers or fuse links must protect the power cables running from the batteries to the inverter.
Leo2 User FORUMHOUSE
If something shorts out in the inverter, then it’s not far from a fire. One of the requirements for battery systems is the presence of a DC breaker or fuse link on at least one of the wires and as close as possible to the battery terminals.
In addition, protection is placed in the battery and controller circuit. Don't neglect protection either. separate groups consumers (DC consumers, household appliances etc.). But this is already a rule for constructing any power supply system.
The machine installed between the battery and the controller must have a large misfire current reserve. In other words, the protection should not operate accidentally (when the load increases). Reason: if voltage is supplied to the controller input (from the power supply), then at this moment the battery cannot be disconnected from it. This may cause the device to malfunction.
Connection procedure
The electrical circuit is assembled in the following order:
- Connecting the controller to the battery.
- Connection to solar panel controller.
- Connection to the controller of a group of DC consumers.
- Connecting the inverter to batteries.
- Connecting the load to the inverter output.
This connection sequence will help protect the controller and inverter from damage.
You can learn from the participants of our portal by visiting the corresponding topic. For those who are seriously interested, we recommend visiting another useful section dedicated to sharing experience in this area. In conclusion, we bring to your attention a video that will tell you how to properly install and connect solar panels.
Living in the "Organic" style, such a popular idea in last years, presupposes a harmonious “relationship” between a person and the environment. The stumbling block to any environmental approach is the use of minerals for energy.
Emissions of toxic substances and carbon dioxide into the atmosphere released during the combustion of fossil fuels are gradually killing the planet. Therefore, the concept of "green energy" that does not harm environment, is the basic basis of many new energy technologies. One of these areas for obtaining environmentally friendly energy is the technology of converting sunlight into electricity. Yes, that’s right, we will talk about solar panels and the possibility of installing autonomous energy supply systems in a country house.
Currently, power plants industrial production based on solar panels, used for the complete energy and heat supply of a cottage, cost at least 15-20 thousand dollars with a guaranteed service life of about 25 years. The cost of any helium system in recalculation of the ratio of the guaranteed service life to the average annual costs of utility maintenance country house quite high: firstly, today the average cost of solar energy is comparable to the purchase of energy resources from central power grids, and secondly, one-time capital investments are required to install the system.
It is usually customary to separate solar systems intended for heat and energy supply. In the first case, technology is used solar collector, in the second - the photoelectric effect for generating electric current in solar panels. We want to talk about the possibility of making solar panels yourself.
Technology hand assembled The solar energy system is quite simple and affordable. Almost every Russian can assemble individual energy systems with high efficiency at relatively low costs. It's profitable, affordable and even fashionable.
Selecting solar cells for a solar panel
When starting to manufacture a solar system, you need to pay attention that with individual assembly there is no need for a one-time installation of a fully functional system; it can be expanded gradually. If the first experience was successful, then it makes sense to expand the functionality of the solar system.
At its core, a solar battery is a generator that operates on the basis of the photovoltaic effect and converts solar energy into electrical energy. Quanta of light striking a silicon wafer knock an electron out of the last atomic orbit of silicon. This effect creates a sufficient number of free electrons to form a flow of electric current.
Before assembling the battery, you need to decide on the type of photoelectric converter, namely: monocrystalline, polycrystalline and amorphous. To assemble a solar battery yourself, choose commercially available monocrystalline and polycrystalline solar modules.
Above: Monocrystalline modules without soldered contacts. Bottom: Polycrystalline modules with soldered contacts
Panels based on polycrystalline silicon have a fairly low efficiency (7-9%), but this disadvantage is offset by the fact that polycrystals practically do not reduce power in cloudy and cloudy weather; the guaranteed durability of such elements is about 10 years. Panels based on monocrystalline silicon have an efficiency of about 13% with a service life of about 25 years, but these elements greatly reduce power in the absence of direct sunlight. Efficiency indicators of silicon crystals from different manufacturers may vary significantly. Based on the practice of operating solar power plants in field conditions, we can say that the service life of monocrystalline modules is more than 30 years, and for polycrystalline modules - more than 20 years. Moreover, over the entire period of operation, the power loss for silicon mono- and polycrystalline cells is no more than 10%, while for thin-film amorphous batteries the power decreases by 10-40% in the first two years.
Evergreen Solar Cells with contacts in a set of 300 pcs.
At the eBay auction you can purchase a Solar Cells kit for assembling a solar battery of 36 and 72 solar cells. Such sets are also available for sale in Russia. As a rule, for self-assembly of solar panels, B-type solar modules are used, that is, modules rejected for industrial production. These modules do not lose their performance characteristics and are much cheaper. Some suppliers offer solar modules on a fiberglass board, which implies a high level of tightness of the elements, and, accordingly, reliability.
| Name | Characteristics | Cost, $ |
| Everbright Solar Cells (Ebay) no contacts | polycrystalline, set - 36 pcs., 81x150 mm, 1.75 W (0.5 V), 3A, efficiency (%) - 13 in a set with diodes and acid for soldering in a pencil |
$46.00 $8.95shipping |
| Solar Cells (USA new) | monocrystalline, 156x156 mm, 81x150 mm, 4W (0.5 V), 8A, efficiency (%) - 16.7-17.9 | $7.50 |
| monocrystalline, 153x138 mm, U cold. stroke - 21.6V, I short. deputy - 94 mA, P - 1.53W, efficiency (%) - 13 | $15.50 | |
| Solar Cells on a fiberglass board | polycrystalline, 116x116 mm, U cold. stroke - 7.2V, I short. deputy - 275 mA., P - 1.5W, efficiency (%) - 10 | $14.50 |
|
$87.12 $9.25 shipping |
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| Solar Cells (Ebay) without contacts | polycrystalline, set - 72 pcs., 81x150 mm 1.8W |
$56.11 $9.25 shipping |
| Solar Cells (Ebay) with contacts | monocrystalline, set - 40 pcs., 152x152 mm |
$87.25 $14.99 shipping |
Development of a helium energy system project
The design of a future solar system largely depends on the method of its installation and installation. Solar panels must be installed at an angle to ensure direct exposure sun rays at right angles. The performance of a solar panel largely depends on the intensity of the light energy, as well as the angle of incidence of the sun's rays. The placement of the solar battery relative to the sun and the angle of inclination depend on the geographical location of the helium system and the time of year.
From top to bottom: Monocrystalline solar panels (80 watts each) at the dacha are installed almost vertically (winter). Monocrystalline solar panels in the country have a smaller angle (spring). Mechanical system for controlling the angle of the solar battery.
Industrial solar systems are often equipped with sensors that ensure the rotational movement of the solar panel in the direction of movement of the sun's rays, as well as solar concentrator mirrors. In individual systems, such elements significantly complicate and increase the cost of the system, and therefore are not used. A simple mechanical tilt angle control system can be used. IN winter time solar panels should be installed almost vertically; this also protects the panel from snow accumulation and icing of the structure.
Scheme for calculating the angle of inclination of a solar panel depending on the time of year
Solar panels are installed with sunny side buildings to provide the maximum amount of solar energy available during daylight hours. Depending on your geographic location and solstice level, the battery angle that is most suitable for your location is calculated.
If the design becomes more complex, it is possible to create a system for controlling the angle of inclination of the solar battery depending on the time of year and the angle of rotation of the panel depending on the time of day. The energy efficiency of such a system will be higher.
When designing a solar system that will be installed on the roof of a house, it is necessary to find out whether roof structure maintain the required weight. Independent development of the project involves calculating the roof load taking into account the weight of the snow cover in winter.
Selecting the optimal static tilt angle for a monocrystalline type roofing solar system
For the manufacture of solar panels, you can choose various materials By specific gravity and other characteristics. When choosing construction materials, it is necessary to take into account the maximum permissible heating temperature of the solar cell, since the temperature of a solar module operating at full power should not exceed 250C. Once the peak temperature is exceeded, the solar module abruptly loses its ability to convert sunlight into electrical current. Ready-made solar systems for individual use, as a rule, do not require cooling of solar cells. Do-it-yourself manufacturing may involve cooling the solar system or controlling the angle of the solar panel to ensure the functional temperature of the module, as well as choosing an appropriate transparent material that absorbs IR radiation.
Proper design of the solar system allows you to provide the required power of the solar battery, which will be close to the nominal one. When calculating a structure, it must be taken into account that elements of the same type give the same stress, regardless of the size of the elements. Moreover, the current strength of large-sized elements will be greater, but the battery will also be much heavier. To manufacture a solar system, solar modules of the same size are always taken, since the maximum current will be limited by the maximum current of the small element.
Calculations show that on average on a clear sunny day you can get no more than 120 W of power from 1 m of solar panel. Such power will not even power a computer. A 10 m system provides more than 1 kW of energy and can provide electricity for the operation of basic household appliances: lamps, TV, computer. For a family of 3-4 people, about 200-300 kW per month is needed, so solar system, installed with south side, 20 m in size can fully meet the family's energy needs.
If we consider the average statistical data on the power supply of an individual residential building, then: daily energy consumption is 3 kWh, solar radiation from spring to autumn is 4 kWh/m per day, peak power consumption is 3 kW (when turned on). washing machine, refrigerator, iron and electric kettle). In order to optimize energy consumption for lighting inside the house, it is important to use AC lamps with low energy consumption - LED and fluorescent.
Making a solar battery frame
An aluminum corner is used as the frame of the solar battery. At the eBay auction you can purchase ready-made frames for solar panels. The transparent coating is selected at will, based on the characteristics that are necessary for a given design.
Solar panel frame kit with glass, starting at $33
When selecting transparent protective material You can also focus on the following material characteristics:
| Material | Refractive index | Light transmittance, % | Specific gravity g/cm 3 | Sheet size, mm | Thickness, mm | Cost, rub./m2 |
| Air | 1,0002926 | — | — | — | — | — |
| Glass | 1,43-2,17 | 92-99 | 3,168 | — | — | — |
| Plexiglas | 1,51 | 92-93 | 1,19 | 3040x2040 | 3 | 960.00 |
| Polycarbonate | 1,59 | up to 92 | 0,198 | 3050 x2050 | 2 | 600.00 |
| Plexiglass | 1,491 | 92 | 1,19 | 2050x1500 | 11 | 640.00 |
| Mineral glass | 1,52-1,9 | 98 | 1,40 | — | — | — |
If we consider the refractive index of light as a criterion for choosing a material. Plexiglas has the lowest refractive index; a cheaper option for transparent material is domestic plexiglass, and polycarbonate is less suitable. Polycarbonate with an anti-condensation coating is available for sale; this material also provides a high level of thermal protection. When choosing transparent materials based on specific gravity and ability to absorb the IR spectrum, polycarbonate will be the best. The best transparent materials for solar panels include those with high light transmittance.
When making a solar battery, it is important to choose transparent materials, which do not transmit the IR spectrum and, thus, reduce the heating of silicon elements, which lose their power at temperatures above 250C. In industry, special glasses with a metal oxide coating are used. The ideal glass for solar panels is considered to be a material that transmits the entire spectrum except the infrared range.
Diagram of absorption of UV and IR radiation by various glasses.
a) ordinary glass, b) glass with IR absorption, c) duplex with heat-absorbing and ordinary glass.
Maximum absorption of the IR spectrum will provide protective silicate glass with iron oxide (Fe 2 O 3), but it has a greenish tint. The IR spectrum is well absorbed by any mineral glass with the exception of quartz; plexiglass and plexiglass belong to the class of organic glasses. Mineral glass is more resistant to surface damage, but is very expensive and unavailable. For solar panels, special anti-reflective, ultra-transparent glass is also used, transmitting up to 98% of the spectrum. This glass also assumes absorption of most of the IR spectrum.
The optimal choice of optical and spectral characteristics of glass significantly increases the photoconversion efficiency of the solar panel.
Solar panel in plexiglass housing
Many solar panel workshops recommend using plexiglass for the front and back panels. This allows contact inspection. However, a plexiglass structure can hardly be called completely sealed, capable of ensuring uninterrupted operation of the panel for 20 years of operation.
Installation of the solar battery housing
The master class shows how to make a solar panel from 36 polycrystalline solar cells measuring 81x150 mm. Based on these dimensions, you can calculate the size of the future solar battery. When calculating the dimensions, it is important to make a small distance between the elements, which will take into account the change in the size of the base under atmospheric influence, that is, there should be 3-5 mm between the elements. The resulting workpiece size should be 835x690 mm with a corner width of 35 mm.
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A homemade solar panel made using an aluminum profile is most similar to a factory-made solar panel. This ensures a high degree of tightness and structural strength. |
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For manufacturing, an aluminum corner is taken, and frame blanks of 835x690 mm are made. To allow fastening of hardware, holes should be made in the frame. |
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Silicone sealant is applied twice to the inside of the corner. |
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Be sure to make sure there are no empty spaces. The tightness and durability of the battery depends on the quality of application of the sealant. |
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Next, a transparent sheet of the selected material is placed in the frame: polycarbonate, plexiglass, plexiglass, anti-reflective glass. It is important to let the silicone dry in the open air, otherwise the fumes will create a film on the elements. |
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The glass must be carefully pressed and fixed. |
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To securely attach the protective glass, you will need hardware. You need to secure the 4 corners of the frame and place two hardware around the perimeter on the long side of the frame and one hardware on the short side. |
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The hardware is fixed with screws. |
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The screws are tightened tightly using a screwdriver. |
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The solar battery frame is ready. Before attaching solar cells, it is necessary to clean the glass from dust. |
Selection and soldering of solar cells
Currently, the eBay auction offers a huge range of products for making solar panels yourself.
Solar Cells kit includes a set of 36 polycrystalline silicon cells, cell leads and busbars, Schottke diodes and a soldering acid pen
Since a solar battery made by yourself is almost 4 times cheaper than a ready-made one, making it yourself is a significant cost saving. You can buy solar cells on eBay that have defects but still remain functional, so the cost of a solar panel can be reduced significantly if you can donate extra appearance batteries.
Damaged photocells do not lose their functionality
For your first experience, it is better to purchase kits for making solar panels; solar cells with soldered conductors are available for sale. Soldering contacts is a rather complex process, the complexity of which is compounded by the fragility of solar cells.
If you purchased silicon elements without conductors, you must first solder the contacts.
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This is what a polycrystalline silicon cell looks like without conductors. |
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The conductors are cut using a cardboard blank. |
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It is necessary to carefully place the conductor on the photocell. |
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Apply soldering acid and solder to the soldering area. For convenience, the conductor is fixed on one side with a heavy object. |
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In this position, it is necessary to carefully solder the conductor to the photocell. While soldering, do not press on the crystal because it is very fragile. |
Soldering elements is quite a painstaking job. If you cannot get a normal connection, you need to repeat the work. According to standards, silver coating on a conductor must withstand 3 soldering cycles under acceptable thermal conditions, but in practice you are faced with the fact that the coating is destroyed. The destruction of silver plating occurs due to the use of soldering irons with unregulated power (65 W), this can be avoided if you lower the power as follows - you need to turn on a socket with a 100 W light bulb in series with the soldering iron. The power rating of a non-regulated soldering iron is too high for soldering silicon contacts.
Even if conductor sellers claim that there is solder on the connector, it is better to apply it additionally. When soldering, try to handle the elements carefully; with minimal force they will burst; Do not stack the elements in a stack; the weight may cause the lower elements to crack.
Assembling and soldering a solar battery
At the first self-assembly It is better to use a marking substrate for the solar battery, which will help position the elements exactly at a certain distance from each other (5 mm).
Marking substrate for solar battery cells
The base is made of a sheet of plywood with corner markings. After soldering, a piece of mounting tape is attached to each element on the reverse side; just press the back panel against the tape, and all elements are transferred.
Mounting tape used for mounting on the back of the solar cell
With this type of fastening, the elements themselves are not additionally sealed; they can expand freely under the influence of temperature, this will not damage the solar battery or break the contacts and elements. Only the connecting parts of the structure can be sealed. This type of fastening is more suitable for prototypes, but can hardly guarantee long-term operation in the field.
The sequential battery assembly plan looks like this:
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Lay out the elements on glass surface. There must be a distance between the elements, which allows for free changes in size without damaging the structure. The elements must be pressed with weights. |
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We carry out soldering according to the electrical diagram below. “Positive” current-carrying paths are located on the front side of the elements, “negative” ones - on the back side. Before soldering, you need to apply flux and solder, then carefully solder the silver contacts. |
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All solar cells are connected using this principle. |
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The contacts of the outer elements are output to the bus, respectively, to “plus” and “minus”. The bus uses the wider silver conductor found in the Solar Cells kit. We also recommend that you remove the “middle” point; with its help, two additional shunt diodes are installed. |
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The terminal is also installed on the outside of the frame. |
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This is what the diagram of connecting elements looks like without a displayed midpoint. |
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This is what the terminal strip looks like with the “middle” point displayed. The “middle” point allows you to install a shunt diode on each half of the battery, which will prevent the battery from discharging when the lighting decreases or one half is darkened. |
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The photo shows a bypass diode on the "positive" output, it resists the discharge of batteries through the battery at night and the discharge of other batteries during partial darkness. Most often, Schottke diodes are used as shunt diodes. They provide less loss in the total power of the electrical circuit. An acoustic cable in silicone insulation can be used as current carrying wires. For isolation, you can use tubes from under the drip. All wires must be firmly fixed with silicone. |
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The elements can be connected in series (see photo), and not through a common bus, then the 2nd and 4th rows must be rotated 1800 relative to the 1st row. |
The main problems in assembling a solar panel are related to the quality of soldering contacts, so experts suggest testing it before sealing the panel.
Panel testing before sealing, mains voltage 14 volts, peak power 65 W
Testing can be done after soldering each group of elements. If you pay attention to the photos in the master class, then the part of the table under the solar elements is cut out. This was done intentionally to determine the functionality of the electrical network after soldering the contacts.
Sealing the solar panel
Sealing solar panels with self-production- This is the most controversial issue among experts. On the one hand, sealing panels is necessary to increase durability; it is always used in industrial production. For sealing, foreign experts recommend using the epoxy compound “Sylgard 184”, which gives a transparent polymerized highly elastic surface. The cost of “Sylgard 184” on eBay is about $40.
Sealant with a high degree of elasticity “Sylgard 184”
On the other hand, if you do not want to incur additional costs, it is quite possible to use silicone sealant. However, in this case, you should not completely fill the elements to avoid them possible damage during operation. In this case, the elements can be attached to the back panel using silicone and only the edges of the structure can be sealed. It is difficult to say how effective such sealing is, but we do not recommend using non-recommended waterproofing mastics; the probability of contacts and elements breaking is very high.
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Before starting sealing, it is necessary to prepare the Sylgard 184 mixture. |
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First, the joints of the elements are filled. The mixture must set to secure the elements to the glass. |
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After fixing the elements, a continuous polymerizing layer of elastic sealant is made; it can be distributed using a brush. |
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This is what the surface looks like after applying the sealant. The sealing layer must dry. After complete drying, you can cover the solar panel with the back panel. |
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This is what the front side of a homemade solar panel looks like after sealing. |
House power supply diagram
Home power supply systems using solar panels are usually called photovoltaic systems, that is, systems that generate energy using the photoelectric effect. For individual residential buildings, three photovoltaic systems are considered: an autonomous energy supply system, a hybrid battery-grid photovoltaic system, a battery-less photovoltaic system connected to central system energy supply.
Each of the systems has its own purpose and advantages, but most often in residential buildings photovoltaic systems with backup batteries and connection to a centralized power grid are used. The power grid is powered using solar panels, in the dark from batteries, and when they are discharged - from the central power grid. In remote areas where there is no central network, liquid fuel generators are used as a backup source of energy supply.
A more economical alternative to a hybrid battery-grid power system would be a batteryless solar system connected to the central grid. Electricity is supplied from solar panels, and at night the network is powered from the central network. Such a network is more applicable for institutions, because in residential buildings most of the energy is consumed in the evening.
Diagrams of three types of photovoltaic systems
Let's consider typical installation battery-grid photovoltaic system. Solar panels, which are connected through a junction box, act as an electricity generator. Next, a solar charge controller is installed in the network to avoid short circuits during peak load. Electricity is accumulated in backup batteries and is also supplied through an inverter to consumers: lighting, household appliances, electric stove and possibly used to heat water. To install a heating system, it is more effective to use solar collectors, which belong to alternative solar technology.
Hybrid battery-grid photovoltaic system with alternating current
There are two types of power grids used in photovoltaic systems: DC and AC. The use of an alternating current network allows you to place electrical consumers at a distance exceeding 10-15 m, as well as provide a conditionally unlimited network load.
For a private residential building, the following components of a photovoltaic system are usually used:
- the total power of solar panels should be 1000 W, they will provide a generation of about 5 kWh;
- batteries with a total capacity of 800 A/h at a voltage of 12 V;
- the inverter must have a rated power of 3 kW with a peak load of up to 6 kW, input voltage 24-48 V;
- solar discharge controller 40-50 A at a voltage of 24 V;
- source uninterruptible power supply to provide a short-term charge with a current of up to 150 A.
Thus, for a photovoltaic power supply system you will need 15 panels with 36 elements, an example of assembly of which is given in the master class. Each panel provides a total power of 65 watts. Solar batteries based on monocrystals will be more powerful. For example, a solar panel of 40 monocrystals has a peak power of 160 W, but such panels are sensitive to cloudy weather. In this case, solar panels based on polycrystalline modules are optimal for use in the northern part of Russia.
This section contains the experiences of different people in making solar panels at home. Various approaches, designs and manufacturing methods. Trials and errors, conclusions and opinions. Over time, other information on the topic will be added. For example, about controllers, circuits and methods of connecting and charging batteries, various ways organizing and optimizing energy consumption and other things that may be useful in matters of using solar energy.
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DIY solar panel, sealing elements with epoxy resin
Fabrication of two solar panels using transparent optical resin. The basis is ordinary window glass, aluminum frame, glass glued with silicone sealant. The result is durable and cheap panels with completely sealed elements. 
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Homemade panel on plexiglass
The elements in this solar panel are sandwiched between two sheets of plexiglass. The back is 4mm, and the front sheet is 2mm. The panel was assembled using mounting tape, the elements inside are held on by small pieces of this tape, and the plexiglass is also glued together around the perimeter with double-sided tape. 
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Sealing elements with conventional silicone sealant
A small photo report on the manufacture of a solar panel and sealing the elements using ordinary cheap silicone sealant. The panel is made with a slightly higher voltage than usual; instead of 36 elements, the panel has four rows of 12 elements for a total of 48 elements. 
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Homemade solar panel filled with epoxy resin
Homemade solar panel (more precisely 3 pieces) from photo of electrical modules 125*125*150, purchased at the OJSC "PHMZ" enterprise. The peculiarity of this solar panel is that the elements are filled with ordinary epoxy resin. The structure on which the panels are attached is portable and can be rotated all 360 degrees, though it turned out to be heavy, but quite reliable. 
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Electrification of a house in a settlement using homemade solar panels
The first part of a large photo story about autonomous power supply to a house in a settlement based on homemade solar panels made from wooden frames. Making the very first panel from elements on an old one window frame and her first tests. 
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Second part, making a new panel
The second panel was made on a large glass where two sets for solar cells were placed at once. The elements were also attached to the glass using tape. The finished glass with soldered elements was inserted into a wooden box, but first a film was spread over the box and the glass was inserted with it, this is to protect the back side from moisture. 
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Part 3, House Wiring and System Upgrades
Now that it became clear that the system was working, by the way, it now consists of 7 panels, it came to the internal wiring around the house. For the batteries, a shelf was made under the ceiling to reduce the length of the wire from the panels, and the wire itself was thickened to reduce losses.Nowadays, not only specialists are involved in alternative energy. Options for autonomous power supplies are also of interest to hobbyists who are familiar with electrical and radio equipment. With regard to solar batteries, the main difficulty in implementing the project is their high price. And if you consider that for a private house you will need several panels, then some skepticism in terms of their use in everyday life becomes understandable.
Although there is a good solution for those who are used to doing everything with their own hands - to assemble a solar battery from separate panels. For example, Chinese ones, which are relatively inexpensive.
From their experience practical application we can conclude that they fully meet the expectations of the master. And if you focus on a class B kit (cheaper products), then significant savings are achieved when assembling the power supply yourself.
To obtain a sample of 145 W with a total voltage of 18 V, you will have to pay about 3,100 rubles for Chinese panels (36 pieces) (if purchased via the Internet, for example, on Alibaba, Ebay) versus 6,180 (the cost of a ready-made analogue of industrial production). It turns out that it makes sense to spend time and make such a battery.
Not only Chinese, but all solar panels are divided into mono- (more expensive) and polycrystalline (amorphous). What is the difference? Without going into manufacturing technology, it is enough to point out that the former are characterized by a homogeneous structure. Therefore, their efficiency is higher than that of amorphous analogues (approximately 25% versus 18%) and they are more expensive.
Visually, they can be distinguished by their shape (shown in the figure) and shade of blue. Monocrystalline panels are slightly darker. Well, whether it makes sense to save on power, you will have to decide for yourself. In addition, it should be taken into account that the production of inexpensive polycrystalline panels in China is mainly carried out by small companies that save on literally everything, including raw materials. This directly affects not only the cost, but also the quality of the product.
All photocells are connected into a single energy chain by conductors. Depending on the type of panels, they may already be fixed in place or missing. This means you will have to solder them yourself. All crystalline samples are quite fragile and must be handled with extreme care.
If you do not have the proper skills to work with a soldering iron, then it is better to purchase class A panels (more expensive). When buying cheap analogues (B), it is advisable to take at least one in stock. The practice of assembling solar panels shows that damage cannot be avoided, therefore extra panel definitely needed.
When determining the required number of photocells, you can rely on such data. 1 m² of panels provides approximately 0.12 kW/hour of electricity. Energy consumption statistics show that for a small family (4 people) about 280 - 320 kW per month is sufficient.
Solar panels are sold in two possible versions - with a wax coating (to protect against damage during transportation) and without it. If the panels have a protective layer, they will have to be prepared for assembly.
What needs to be done?
- Unpack the goods.
- Load the kit into hot water. Approximate temperature – 90±5 0С. The main thing is that it is not boiling water, otherwise the panels will be partially deformed.
- Separate samples. Signs that the wax has melted are visible visually.
- Process each panel. The technology is simple - alternately immerse them in hot soapy water, then clean. The “washing” procedure continues until there are no traces of wax left on the surface.
- Dry. The panels should be laid out soft fabric. For example, on a terry tablecloth.
Assembly order
Specifics of frame manufacturing
In essence, it is traditional simple frame, the material for which is selected depending on the location of the battery. Typically, on thematic websites, aluminum corner or wood is indicated. The advisability of using the latter (with all due respect to the authors of the articles) raises certain doubts. The main reason is the characteristics of any tree. It consists of moisture content, regardless of the degree of drying.
No matter how many percent it is, twisting and even cracking of the wood cannot be avoided. Given the fragility of the panels, this is definitely not an option. This kind of thing, even if attached to a window inside a building, will not last long.
Battery installation
The frame dimensions are selected based on the linear parameters of the panels. Horizontal or vertical orientation - this depends on the specifics of the battery installation, and is not of fundamental importance.
A sheet of glass or polycarbonate (not cellular, but monolithic) is attached to the frame. It performs a protective function, protecting photocells from mechanical destruction.
Drops of silicone sealant are applied to it, from the inside of the frame (in the center of the panels), or it is spread with a thin layer. Recommendations for the use of resin (epoxy) are hardly worthy of attention, since in this case there is no talk about the maintainability of the battery.
The calculated number of panels is placed in the frame (assembly is done in advance). One gives a voltage of about 0.5 V (a small deviation in the nominal value does not count). Here it is important not to confuse where the front side of the products is and where the back is.
The back is covered with a soft, removable mat. To make it yourself, you can take foam rubber (4 cm, at least) and P/E film. Its edges are connected with tape or soldered (if you have a special machine).
The work doesn't end there. Air bubbles will remain between the glass (polycarbonate) and the panels, which reduces the efficiency of the solar panel. They need to be removed. To do this, dense material is laid on the mat. For example, a fragment selected according to the size of the frame, thick (multi-layer) plywood.
On top is a load whose weight is sufficient to lightly press down the panels. The battery is left in this position for at least half a day. Here you should focus on its dimensions and uniform load distribution.
After this time, the bending, plywood and mat are dismantled. You cannot immediately attach the battery to the installation site. It will take some more time for the sealant to completely dry.
Instead of a mat, you can use another soft substrate. For example, sawdust, shavings.
The final stage is making the back wall and putting it in place. To do this, use chipboard, fiberboard, plywood, but always with the same backing to protect the panels from deformation.
Circuit assembly features
Soldering plates is a complex process that requires painstaking and careful attention. It is better to work with a low-power soldering iron (24 - 36 W). If you use 65, which is common in everyday life, then it should be turned on through a limiting resistance. The simplest option– serial connection of a 100-watt light bulb.
But that's not all. It is necessary to prevent self-discharge of the battery (at night, in inclement weather). This is ensured by the inclusion of semiconductor diodes in the circuit. It is advisable to use an acoustic cable as a conductor (for terminals), which is also fixed on the panel with sealant.
The option of a film solar battery (there is one) is not being considered. Despite some advantages, it has a number of significant disadvantages– low efficiency and the need for installation on large areas. This is an unacceptable solution for a private home.