DIY solar generator: instructions for making an alternative energy source 

What do you need for work?

To manufacture a generator consisting of a set of solar panels, the following tools and materials are required:

• modules for converting sunlight into energy;
• aluminum corners;
• wooden slats;
• chipboard sheets;
• a transparent element (glass, plexiglass, plexiglass, polycarbonate) to create protection for silicon wafers;
• self-tapping screws and screws of different sizes;
• dense foam rubber 1.5-2.5 mm thick;
• high-quality sealant;
• diodes, terminals and wires;
• screwdriver or set of screwdrivers;
• soldering iron;
• hacksaw for wood and metal (or grinder).

The volume of materials needed will directly depend on the planned size of the generator. Large-scale work will entail additional costs, but in any case it will be cheaper than a purchased module.

The protective base for silicon wafers can be made of glass, plexiglass, polycarbonate or plexiglass. The first three materials create minimal loss of converted energy, but the fourth transmits rays much worse and significantly reduces the efficiency of the entire complex

For final testing of the assembled unit, an ammeter is used. It allows you to record the real efficiency of the installation and helps determine the actual output.

Reviews

Judging by the reviews existing on the Internet, a fairly large number of people speak positively about the installation of such devices. Solar power plants for home, reviews of which can be found, are usually installed in remote parts and have no analogues in terms of convenience, comfort and cost. Yes, they really are still too expensive to fully replace centralized supply. But, firstly, this is only for now, and secondly, sooner or later such a power plant pays for itself and begins to save money. As was already said at the very beginning, cheap stations will help you gain profit within 5-10 years. Expensive and more powerful models rarely pay for themselves longer than 40 years. Some people have longer mortgages. One-time serious expenses will still be compensated, but you will have to pay for central electricity until the very last days of your life.

Sources used:

solarpanel.today, term.od.ua, energo.house, www.syl.ru, altenergiya.ru, sovets24.ru, www.asutpp.ru, m.habr.com, motocarrello.ru

Selecting the type of photoconverter

Activities to create a solar generator with your own hands begin with choosing the type of photovoltaic silicon converter.

These components come in three types:

• amorphous;
• monocrystalline;
• polycrystalline.

Each option has its own advantages and disadvantages, and the choice in favor of any of them is made based on the amount of funds allocated for the purchase of all system components.

Features of amorphous varieties

Amorphous modules do not consist of crystalline silicon, but of its derivatives (silane or hydrogen silicon). By spraying in a vacuum, they are applied in a thin layer to high-quality metal foil, glass or plastic.

The finished products have a faded, blurry gray tint. No visible silicon crystals are observed on the surface. The main advantage of flexible solar panels is their affordable price; however, their efficiency is very low and ranges from 6-10%.

Amorphous solar cells made from silicon have increased flexibility, exhibit high levels of optical absorption (20 times greater than mono- or polycrystalline counterparts) and operate significantly more efficiently in cloudy weather

Specifics of polycrystalline types

Polycrystalline solar cells are produced by gradually cooling a silicon melt very slowly. The resulting products are distinguished by a rich blue color, have a surface with a clearly defined pattern reminiscent of a frosty pattern, and exhibit an efficiency of around 14-18%.

Higher efficiency performance is hampered by the areas present inside the material, separated from the overall structure by granular boundaries.

Polycrystalline solar cells operate for only 10 years, but during this time their efficiency does not decrease. However, to install products into a single complex, a strong, solid base must be used, since the sheets are quite rigid and require strong, reliable support

Characteristics of monocratylic variants

Monocrystalline modules are characterized by a dense dark color and consist of solid silicon crystals. Their efficiency exceeds that of other elements and amounts to 18-22% (under favorable conditions - up to 25%).

Another advantage is the impressive service life - according to the manufacturers, over 25 years. However, with prolonged use, the efficiency of single crystals decreases and after 10-12 years the photoreturn is no more than 13-17%.

Monocrystalline modules are significantly more expensive than other types of equipment. They are produced by sawing artificially grown silicon crystals

To create a solar generator at home with your own hands, you mainly take poly- and monocrystalline plates of various sizes. They are purchased from popular online stores, including eBay or Aliexpress.

Due to the fact that photocells are valued quite highly, many suppliers offer customers products of group B, that is, fragments suitable for full use with a slight defect. Their cost differs from the standard price by 40-60%, so assembling a generator costs a reasonable price that is not too expensive.

Real output of a solar power plant for a home

The output depends on the power and angle of inclination of the panels, the intensity of the sun and the length of daylight hours.

Batteries differ in area, which affects their power. It can be 10W, 100W, 150W, 260W and so on. However, the actual output of the panel is usually higher than its rated power, since the solar intensity factor must be taken into account. In the southern regions the sun shines stronger and longer, and in the northern regions it shines weaker and less, so the same panel produces different amounts of electricity.

Case Study

This is a graph of electricity production from one 260W panel for June 2022. The total output of the station for the month is 34.89 kW. Based on the calculation that the nominal monthly power of the battery is 7.8 kW (260 W X 30 days), its actual power turned out to be 4.5 times higher (correction factor). In summer it is larger, in winter it is smaller or absent altogether.

The graph shows that production is not constant and there are sharp drops - these are cloudy days, when daylight hours are shorter and solar activity is very weak. The worst performance was recorded on June 17 - about 0.4 kW, and the maximum on June 25 - about 1.4 kW.

And this is what the output of a solar battery looks like hourly during the day:

Production starts around 9am, peaks around 1pm, then gradually declines and stops around 7pm. During the day there are small dips - when the sun was hidden by clouds.

Power generation was unstable from approximately 1:00 pm to 3:00 pm due to cloud cover. But this did not greatly affect the final performance of the station - 1.32 kW.

There were many failures during the day, which affected the final output of the station - 0.98 kW.

And this is a cloudy rainy day, when solar activity is very weak and the generation during the day was 0.45 kW.

From this we can conclude that relying entirely on solar electricity is difficult. The performance of the station is highly dependent on the intensity of the sun and even in summer it can be inconsistent due to cloudy weather.

How to make a frame for plates?

To make the frame of the future generator, strong wooden slats or aluminum corners are used. The wooden version is considered less practical, since the material requires additional processing to avoid subsequent rotting and delamination.

In order for the wooden frame to withstand the operational load and not rot after the first rain, it must be impregnated with a special composition that protects the wood from moisture.

Aluminum has much more attractive physical characteristics and, due to its lightness, does not place unnecessary stress on the roof or other supporting structure where the unit is planned to be installed.

In addition, due to the anti-corrosion coating, the metal does not rust, does not rot, does not absorb moisture and easily withstands the effects of any aggressive atmospheric manifestations.

To create a frame structure from aluminum corners, first determine the size of the future panel. In the standard version, 36 photocells measuring 81 mm x 150 mm are used per block.

For correct subsequent operation, a small gap (about 3-5 mm) is left between the fragments. This space allows us to take into account changes in the basic parameters of the base exposed to atmospheric manifestations. As a result, the total size of the workpiece is 83 mm x 690 mm with a frame corner width of 35 mm.

Silicon wafers placed in an aluminum profile frame look almost like factory-made products. A durable and strong frame provides the system with impeccable tightness and gives the entire structure a high level of rigidity

After determining the dimensions, the necessary fragments are cut out from the corners and assembled into frame frames using fasteners. A layer of silicone sealant is applied to the inner surface of the structure, making sure that there are no gaps or voids.

The integrity, strength and durability of the mounted structure depends on this. A protective transparent material is placed on top (glass with anti-reflective coating, plexiglass or polycarbonate with special parameters) and securely fastened with hardware (1 per short and 2 per long part of the frame and 4 at the corners of the body).

For work, use a screwdriver and screws of a suitable diameter. At the end, the transparent surface is carefully cleaned of dust and small debris.

Selecting a transparent element

The main criteria for choosing a transparent element to create a generator:

• ability to absorb infrared radiation;
• level of refraction of sunlight.

The lower the refractive index, the higher the efficiency the silicon wafers will demonstrate. Plexiglas and plexiglass have the lowest coefficient of light reflection. Polycarbonate also has far from the best performance.

To create frame structures for home solar systems, it is recommended, if possible, to use anti-reflective transparent glass or a special type of polycarbonate with an anti-condensation coating that provides the necessary level of thermal protection.

The best characteristics in terms of absorption of IR radiation have durable thermal-absorbing plexiglass and glass with an IR absorption option. For ordinary glass these figures are significantly lower. The efficiency of IR absorption determines whether the silicon wafers will heat up during operation or not.

If the heating is minimal, the photocells will last a long time and provide stable output. Overheating of the plates will lead to interruptions in operation and rapid failure of individual parts of the system or the entire complex.

How to connect if there is electricity on the site

If the site is connected to the network, then installing a solar power plant will make the house more energy independent, reduce energy costs and even make money on it thanks to the feed-in tariff.

• DIY solar cell assembly

There is no battery in this connection scheme, since there is no need to store electricity (but if you want to have a backup power source in case the lights go out, then a battery is required).

To connect such a station, you only need a solar battery (or several), which is connected to an outlet through a network inverter. In this form, the station is already ready for operation. The battery generates electricity and you immediately consume it for internal needs: running the refrigerator, lighting, kettle, etc.

Photo of real power plant connection

For example, the station’s daily output is 1 kW of electricity, and the building consumes a total of 5 kW. In fact, you only take 4 kW from the network. But if the station produces 5 kW per day, and you actually consume only 2 kW, then the remainder (3 kW) is burned. In this case, you can connect a green tariff and sell the difference to the state at a higher price, or install a battery and accumulate the excess for it.

Now there are companies that connect green tariffs on a turnkey basis. Starting from the selection and installation of the station to the conclusion of an agreement with OBLENERGO.

How to test the installed unit?

Before finally sealing the assembled generator, it must be tested in order to identify potential malfunctions during the soldering process. The most reasonable option is to check each soldered row separately. This way it will immediately become clear where the contacts are poorly connected and require re-processing.

To carry out the test, use a household ammeter. The measurement is carried out on a cloudless sunny day at lunchtime (from 1 to 3 p.m.). The structure is placed in the yard and installed at the appropriate angle of inclination.

A household ammeter helps measure the actual current. Based on its readings, it is possible to determine the level of performance of the mounted solar system and identify violations in the sequence of connection of silicon photocells

An ammeter is connected to the output contacts of the solar battery and the short circuit current is measured. If the device shows results above 4.5 A, the system is completely correct and all connections are soldered clearly and correctly.

Lower data that appears on the tester display indicates violations that need to be tracked and re-soldered. Traditionally, do-it-yourself solar generators from photocells with a slight defect (group B) show figures from 5 to 10 Amperes on the test.

Factory-produced units show data 10-20% higher. This is explained by the fact that the production uses silicon wafers of group A, which do not have any defects in the structure.

How much power does a family need?

On average, one family of three, taking into account a full set of equipment and an electric stove (and these are the ones most often found in houses, because running gas is even more difficult than running power lines) consumes 6-7 kW per day. And this is in an apartment. In the house, consumption will be even higher, because you need to additionally heat water, ensure the operation of the sewage system, and much more. Thus, we can conclude that a 5 kW solar power plant for a home will still not be able to provide everything needed. But if you cut down on your appetite and activate only what you need at the moment, you can get by with that amount. Ultimately, this is still significantly better than no power supply at all. The same refrigerator will be able to work around the clock, like other basic devices. But the TV, computer and other similar devices will have to be turned on only occasionally, which, in principle, is not as critical as it might seem.

The final stage of work

If the test shows that the battery is fully functional, it is sealed with a special silicone sealant or a more expensive and durable epoxy compound.

The work involves two ways of doing it:

1. Full filling - when the entire surface is covered with a sealing compound.
2. Partial treatment - when the sealant is applied only to the outer elements and the empty space between the elements.

The first option is considered more reliable and provides the system with complete protection from external factors. Photocells are clearly fixed in place and work correctly with maximum efficiency.

To seal photocells inside the housing, it is advisable to use a frost-resistant sealant that can withstand sudden temperature changes and low subzero temperatures.

When the filling is completed, the sealant is allowed to “set.” Then they cover it with a transparent element and press it tightly against the plates.

In order to provide additional protection and shock absorption, some craftsmen recommend placing dense foam rubber between the surface of the silicon slab and the back of the frame. This will make the structure more integral and protect fragile photocells from unnecessary load.

Then a weight is placed on the surface, which acts on the layers and squeezes air bubbles out of them. The finished generator is tested again and finally installed in a pre-prepared place.

Do-it-yourself autonomous solar power plant for home

It is not difficult to assemble your own solar station; it contains only four components:

• solar panels;
• battery charge;
• controller;
• inverter

Solar power plant diagram

All of them are easy to find and order through online stores. But how to make a solar power plant with your own hands in order to create a full-fledged autonomous power supply system at home? First, you need to collect information about your needs, the capabilities of the area where the solar station will operate, and make all the necessary calculations for selecting the components.

How to calculate the number of solar panels

Choosing a solar station begins with searching for information on insolation in your area - the amount of solar energy that hits the earth's surface (measured in watts per square meter). This data can be found in special weather reference books or on the Internet. Typically, insolation is indicated separately for each month, because the level is highly dependent on the season. If you plan to use the solar station all year round, then you need to focus on the months with the lowest indicators.

Next, you need to calculate your electricity needs for each month. Remember that for an autonomous power supply system, not only the efficiency of energy storage plays a role, but also its economical use. Smaller needs will allow you to save significantly when purchasing solar panels and creating a budget version of a solar power station with your own hands.

Compare your electricity needs with the level of insolation in your area and you will find out the area of ​​solar panels that is needed for your solar station. Please note that the efficiency of the panels is only 12-14%. Always focus on the lowest figure.

• DIY absorber assembly for a solar collector

Thus, if the insolation level in the most unfavorable month in your area is 20 kWh/m², then with an efficiency of 12% one panel with an area of ​​0.7 m² will produce 1.68 kWh. Your energy requirement, for example, is 80 kWh/month. This means that in the least sunny month, 48 panels (80/1.68) will be able to satisfy this need. You can read more about how to choose solar panels in our previous article. And here you can learn how to make candles at home.

How to choose solar panels

Solar panel device

At first glance, all solar panels are the same: the cells of solar cells are interconnected by busbars, and on the back side there are two wires: plus and minus. But there are a lot of nuances in this matter. Solar panels come from different elements: amorphous, polycrystalline, monocrystalline. I will not advocate for one type of element or another. Let me just say that I myself prefer monocrystalline solar panels. But that's not all. Each solar battery is a four-layer cake: glass, transparent EVA film, solar cell, sealing film. And here every stage is extremely important. Not just any glass is suitable, but with a special texture, which reduces the reflection of light and refracts light incident at an angle so that the elements are illuminated as much as possible, because the amount of energy generated depends on the amount of light. The transparency of the EVA film determines how much energy reaches the element and how much energy the panel generates. If the film turns out to be defective and becomes cloudy over time, then production will drop noticeably.

Next come the elements themselves, and they are distributed by type, depending on quality: Grade A, B, C, D and so on. Of course, it is better to have quality A elements and good soldering, because with poor contact, the element will heat up and fail faster. Well, the finishing film should also be of high quality and provide good sealing. If the panels become depressurized, moisture will quickly enter the elements, corrosion will begin, and the panel will also fail.

How to choose the right solar panel? The main manufacturer for our country is China, although there are also Russian manufacturers on the market. There are a lot of OEM factories that will paste any ordered nameplate and send the panels to the customer. And there are factories that provide a full production cycle and are able to control product quality at all stages of production.

How can you find out about such factories and brands? There are a couple of reputable laboratories that conduct independent tests of solar panels and openly publish the results of these tests. Before purchasing, you can enter the name and model of the solar panel and find out how well the solar panel matches the stated characteristics. The first laboratory is the California Energy Commission, and the second European laboratory is TUV. If the panel manufacturer is not on these lists, then you should think about quality. This doesn't mean the panel is bad. It’s just that the brand may be OEM, and the manufacturing plant also produces other panels. In any case, the presence in the lists of these laboratories already indicates that you are not buying solar panels from a fly-by-night manufacturer.

How to install a solar panel

For the best efficiency, the solar panel should be installed so that the sun's rays fall on it at an angle of 90 degrees. Since the sun constantly moves across the sky, there are two solutions:

• Dynamic installation. Use a servo to make the solar panel rotate as the sun moves across the sky. The servo drive will allow you to collect 50% more energy than a static installation.
• Stationary installation. To get the most out of the fixed position of the solar panel, you need to find the installation angle at which the panel will collect the maximum possible amount of sun rays. For year-round operation, this angle is calculated using the formula +15 degrees to the latitude of the area. For the summer months this is -15 degrees to the latitude of the area.

How to choose a charge controller

Another way to build your own solar power plant and make it work efficiently is to use a charge controller that allows you to track maximum power points (MPPT). Such a controller can store energy even during low light conditions and continues to supply it to the battery in an optimal manner.

How to choose a battery

So, energy from solar panels goes to the battery. This allows energy to be stored so that it can be used even in the absence of sunlight. In addition, batteries smooth out uneven energy supply, for example, during strong winds or clouds.

Installing solar panels may require a large roof slope

To correctly select and install a battery for a home solar power station with your own hands, you need to consider two parameters:

• It is very important that the charging current (from the panels) does not exceed 10% of the rated capacity level for acid batteries and 30% for alkaline devices.
• Low side voltage inverter design.

Consider battery self-discharge rates (not always indicated by manufacturers). For example, acid devices are recharged every six months to avoid breakdown.

How to choose an inverter

Description of parameters and mandatory functions of an ideal inverter:

• sinusoidal signal with distortion not exceeding three percent;
• when a load is connected, the voltage amplitude changes by no more than ten percent;
• double current conversion - direct and alternating;
• analogue AC conversion part with a good transformer;
• short circuit protection;
• overload reserve.

When modeling your home's electrical system, group the loads so that different types of loads are powered by different inverters.

Where and how to place the generator?

The location for installing the solar generator is chosen very carefully and without haste. The plates that receive light must be placed at an angle so that the rays do not “fall” perpendicularly to the surface, but seem to “flow” neatly along it.

Ideally, the structure is positioned so that it remains possible, if necessary, to adjust the angle of inclination, in this way, “catching” the maximum amount of sun.

It is quite acceptable to install a solar system from solar panels on the ground, but most often the roof of a house or utility room is chosen for placement, namely that part of it that faces the most consecrated, mainly southern side of the site.

It is very important that there are no tall buildings or powerful, spreading trees nearby. Being in close proximity, they create a shadow and interfere with the full operation of the unit.

For solar installations to perform well, they must be kept clean and tidy. A layer of dirt formed on the surface of the catching panel reduces efficiency by 10%, and adhered snow completely shuts down the unit. Therefore, regular maintenance is a must and helps keep the modules in perfect operating condition.

The average roof slope level for installing a solar generator is considered to be 45⁰. With this arrangement, photocells absorb solar flux very efficiently and produce the amount of energy necessary for the correct functioning of the house.

To get real returns from the panels and provide the average family with the required amount of energy, you will have to occupy 15-20 sq.m of roof surface for a solar generator

For the European part of the CIS countries, slightly different indicators apply. Professionals recommend using a stationary tilt angle of 50-60⁰ as a basis, and in movable structures during the winter season placing the batteries at an angle of 70⁰ to the horizon.

In summer, change the position and tilt the photocells at an angle of 30⁰.

By installing generator panels on a track system equipped with an automatic sun tracking option, you can increase the output efficiency by 50%. The module will independently detect the intensity of the rays and will adjust to the maximum illumination from dawn to sunset

Immediately before installation, the roof is additionally strengthened and equipped with special strong supports, since not every structure is able to withstand the full weight of equipment for converting solar energy.

To reliably and firmly install a solar generator on the roof, it is worth purchasing special fastenings. They are produced separately for each type of roofing and are always available for sale. When installing between the panels and the roof, it is necessary to leave a gap for full access of air and correct ventilation of the sun-absorbing elements

In some cases, reinforced rafters are placed under the roof to protect the roof from collapse, potentially due to increased load, which increases significantly in the winter season when snow accumulates on the roofing surface.

To put the solar system into operation, you will need batteries, an inverter and a charge controller. You will learn about the rules for selecting devices and their inclusion in the circuit from the articles we recommend.

Advantages of solar power plants

Power plants running on solar energy have a number of advantages compared to traditional sources:

• Modern installations amplify light in the presence of a large concentration of clouds, using rays that are in the invisible frequency spectrum, which ensures their continuous operation.
• They allow you to combine types of energy obtained from different sources: wind-solar batteries are mainly used.
• Compactness . Portable mobile power stations are made in small sizes, which helps to use them as a home source of electricity.
• Long service life, averaging from 30 to 50 years . By connecting storage batteries, you can store energy and use it at night.
• Save on bills because solar energy is free.
• Cheap, durable and easy to maintain.

Important! A home SES allows you to lead an autonomous existence, independent of the state of the power grid, changes in tariffs and other decisions of the owners of resource companies.