How to connect solar panels. Solar batteries for home: application and connection diagrams

Alternative energy is becoming more accessible. This article will give you a complete understanding of local solar energy, types of solar cells and panels, principles of building solar farms and economic feasibility.

Features of solar energy in mid-latitudes

For residents of mid-latitudes, alternative energy is very attractive. Even in northern latitudes, the average annual daily radiation dose is 2.3-2.6 kWh/m2. The closer to the south, the higher this figure. In Yakutsk, for example, the intensity of solar radiation is 2.96, and in Khabarovsk - 3.69 kWh/m2. Indicators in December range from 7% to 20% of the annual average, and double in June and July.

Here is an example of calculating the efficiency of solar panels for Arkhangelsk, a region with one of the lowest solar radiation intensity:

• Q is the average annual amount of solar radiation in the region (2.29 kWh/m2);
• To off - coefficient of deviation of the collector surface from the southern direction (average value: 1.05);
• P nom - rated power of the solar panel;
• Kpot - loss coefficient in electrical installations (0.85-0.98);
• Q test is the radiation intensity at which the panel was tested (usually 1000 kWh/m2).

The last three parameters are indicated in the panels' passport. Thus, if KVAZAR panels with a rated power of 0.245 kW operate in the conditions of Arkhangelsk, and losses in the electrical installation do not exceed 7%, then one block of photocells will provide generation of about 550 Wh. Accordingly, for an object with a nominal consumption of 10 kWh, about 20 panels will be needed.

Economic feasibility

The payback period for solar panels is easy to calculate. Multiply the daily amount of energy produced per day by the number of days in a year and by the service life of the panels without reducing power - 30 years. The electrical installation discussed above is capable of generating on average from 52 to 100 kWh per day, depending on the length of daylight hours. The average value is about 64 kWh. Thus, in 30 years, the power plant should, in theory, generate 700 thousand kWh. With a single-rate tariff of 3.87 rubles. and the cost of one panel is about 15,000 rubles, the costs will pay off in 4-5 years. But the reality is more prosaic.

The fact is that December values ​​of solar radiation are approximately an order of magnitude lower than the annual average. Therefore, for fully autonomous operation of a power plant in winter, 7-8 times more panels are required than in summer. This significantly increases the investment, but reduces the payback period. The prospect of introducing a “green tariff” looks quite encouraging, but even today it is possible to conclude an agreement for the supply of electricity to the network at a wholesale price that is three times lower than the retail tariff. And even this is enough to profitably sell 7-8 times the surplus of generated electricity in the summer.

Main types of solar panels

There are two main types of solar panels.

Solid silicon solar cells are considered first generation cells and are the most common: about 3/4 of the market. There are two types of them:

• monocrystalline (black) have high efficiency (0.2-0.24) and low price;
• polycrystalline (dark blue) are cheaper to produce, but less efficient (0.12-0.18), although their efficiency decreases less with diffused light.

Soft solar cells are called film cells and are made either from silicon deposition or by a multilayer composition. Silicon elements are cheaper to produce, but their efficiency is 2-3 times lower than crystalline ones. However, in diffused light (twilight, cloudy conditions) they are more effective than crystalline ones.

Some types of composite films have an efficiency of about 0.2 and cost much more than solid elements. Their use in solar power plants is very questionable: film panels are more susceptible to degradation over time. Their main area of ​​application is mobile power plants with low energy consumption.

In addition to a block of photocells, hybrid panels also include a collector - a system of capillary tubes for heating water. Their advantage is not only in saving space and the possibility of hot water supply. Due to water cooling, photocells lose less performance when heated.

Table. Review of manufacturers

Equipment for solar energy complex

The batteries generate a direct current of up to 40 V during operation. To use it for domestic purposes, a number of transformations are required. The following equipment is responsible for this:

1. Battery pack. Allows you to use the generated energy at night and during low-intensity hours. Gel batteries with a nominal voltage of 12, 24 or 48 V are used.
2. Charge controllers maintain the optimal battery cycle and transfer the required power to power consumers. The necessary equipment is selected according to the parameters of the batteries and accumulators.
3. The voltage inverter transforms direct current into alternating current and has a number of additional functions. Firstly, the inverter sets priority to the voltage source, and if there is insufficient power, it “mixes” power from another. Hybrid inverters also allow you to feed excess generated energy into the city grid.

1 - solar panels 12 V; 2 - solar panels 24 V; 3 - charge controller; 4 - battery 12 V; 5 - lighting 12 V; 6 - inverter; 7—smart home automation; 8 — battery block 24 V; 9 - emergency generator; 10 - main consumers 220 V

Household use

Solar panels can be used for absolutely any purpose: from compensation of received energy and powering individual lines to complete autonomy of the energy system, including heating and hot water supply. In the latter case, the large-scale use of energy-saving technologies - recuperators and heat pumps - plays an important role.

For mixed use of solar energy, inverters are used. In this case, power can be directed either to the operation of individual lines or systems, or partially compensate for the use of city electricity. A classic example of an efficient energy system is a heat pump powered by a small solar power plant with a bank of batteries.

1 - city network 220 V; 2 - solar panels 12 V; 3 - lighting 12 V; 4 - inverter; 5 - charge controller; 6 - main consumers 220 V; 7 - battery

Traditionally, panels are installed on the roofs of buildings, and in some architectural solutions they completely replace the roofing covering. In this case, the panels must be oriented to the south side so that the incidence of the rays on the plane is perpendicular.

Solar energy is a real find for obtaining cheap electricity. However, even one solar battery is quite expensive, and in order to organize an effective system you need a considerable number of them. Therefore, many people decide to assemble a solar battery with their own hands. To do this, you need to know how to solder a little, since all the elements of the system are assembled into tracks and then attached to the base.

The main and rather difficult task is to find and buy photoelectric converters. They are silicon wafers that convert solar energy into electricity. Photocells are divided into two types: monocrystalline and polycrystalline. The former are more efficient and have a high efficiency of 20-25%, while the latter are only up to 20%. Polycrystalline solar cells are bright blue and less expensive. And mono can be distinguished by its shape - it is not square, but octagonal, and their price is higher.

If soldering is not very good, then to connect a solar battery with your own hands, it is recommended to purchase ready-made solar cells with conductors. If you are sure that you can solder the elements yourself without damaging the converter, you can purchase a kit in which the conductors are included separately.

Growing crystals for solar cells yourself is a rather specific task, and it is almost impossible to do it at home. Therefore, it is better to buy ready-made photocells.

How to choose and where to purchase converters

It will be cheaper to purchase photocells on Chinese Internet sites, although, of course, they often sell defective factory parts. For a start, this is not bad, especially since their price is lower. And after you gain experience in assembling batteries, you can take higher quality parts from the factory.

Some sellers sell converters all en masse sealed in wax so that they are not damaged during transportation, because silicon wafers are fragile, like crystal. Cleaning them of wax is a very labor-intensive task. First you need to immerse them in hot water and after the wax has melted, very carefully separate them. Afterwards, you need to immerse each photocell in a soapy solution, and then in clean hot water. And so on until the wax leaves the plates completely. Then you need to lay them out to dry on a terry towel. In general, this is extra hassle, so it is better to buy plates without wax.

It is safe to purchase photocells for installing solar panels yourself on trusted Chinese sites Ebay and Alibaba. To purchase, you need to register and enter the desired query in the search bar. Several suggestions will be displayed on the screen.

You need to choose not only for the reasons that you liked this particular product - you must definitely pay attention to the reviews and rating of the seller. If you don’t want to pay twice as much for an item due to paid shipping, you need to see if the selected item has a “free shipping” option. If not, this is not a suitable option, since it is too costly.

Money for the goods must be transferred immediately. They will be sent to the seller only after confirmation of receipt of the goods by the buyer. You can pay directly with a payment card or through intermediate services - it all depends on the degree of trust in such online trading resources. You can also return the product, but it is better to immediately purchase from a seller with a good reputation in order to avoid litigation regarding the return. The parcel can take a month or a month and a half - this is already at the mercy of the post office.

Soldering and assembly of panels

Do-it-yourself solar panel assembly can be divided into three stages:

1. Frame production;
2. Soldering of photoelectric converters;
3. Installing them into the frame and sealing them.

The frame can be made from wooden planks or welded from aluminum corners. One way or another, its dimensions, shape and choice of materials for manufacturing directly depend on how it will be mounted.

Required materials and tools

To assemble a solar battery you will need the following materials:

• aluminum or steel corner with a section of 25x25;
• bolts 5x10 mm – 8 pcs;
• nuts 5 mm – 8 pcs;
• glass or polycarbonate 5-6 mm;
• glue – sealant Sylgard 184;
• glue – sealant Ceresit CS 15;
• polycrystalline converters;
• flux marker (a mixture of rosin and alcohol);
• silver tape for connecting to panels;
• tire tape;
• fine solder;
• foam rubber - 3 cm, sawdust or shavings;
• dense polyethylene film 10 microns.

Tools needed for assembly:

• file;
• hacksaw for metal with blade 18;
• drill, 5 and 6 mm drills;
• open-end wrenches;
• soldering iron

Assembly steps

Assembly consists of several stages:

1. First you need to decide on the dimensions of the frame frame. They will depend on the dimensions of the panels themselves and their quantity. When solar panels are placed on the roof, the panels can completely cover the slope or occupy a small part of it - there are no specific rules, so what width and length the frame will be is chosen by the assembler himself.
2. It is necessary to install glass on top of the frame to protect the photocells from destruction. It can be secured with a thin layer of silicone sealant, but it is better not to use epoxy resin for these purposes, since it will be extremely difficult to remove the glass in case of need for repair work without damaging the panels.
3. When connecting solar panels to the network, it is better to choose a mixed scheme, as it is optimal. The assembled panels are placed into a previously prepared frame. At this stage, it is important not to confuse the back of the panel with the front.
4. To protect the back of the battery during assembly, you can make a foam mat and wrap it in plastic wrap. Sawdust or shavings are also suitable, but the main thing is that their particles do not remain on the elements.
5. After this, you need to remove air bubbles that form between the photocells and the glass, since their presence will interfere with the efficient operation of the battery. To do this, you need to place a load on the panel and a hard sheet of plywood on the soft mat. Thus, the photocells become jammed and must be left like this for half a day. Then the weight is removed, and the plywood and mat are removed. It is too early to install the battery after this; the sealant needs to fully set.
6. The last stage is the manufacture of the back wall of the battery from chipboard or fiberboard with a backing - this will prevent deformation of the panels.

Possible installation locations

There are several different options available for installation location:

1. If you decide to install solar panels on the roof, then its slope should be no more than 40 degrees. This option involves using profiles as a supporting structure for a solar battery. If the roof slope is 30-40 degrees, you can install solar panels without a bracket.
2. To install a solar battery on a flat roof, you will have to make a frame with a special inclined stand, since the structure must be sloped towards the roof of the house.
3. Installing solar panels on the wall is quite rare. In this case, as in others, you will need a steel inclined frame, which will ensure that the battery is located at an angle.
4. If the area is characterized by heavy rainfall in winter, the installation can be placed on the ground. To do this, you will need to support it on a special rod.
5. The battery can be placed on the roof of a balcony or loggia, if it is the top floor of a private house or the apartment is on the top floor. If insolation allows, then you can install a solar panel on the outside of the balcony.

System connection diagrams

The solar panel connection diagram consists of several devices:

1. A solar panel, which will accumulate light and convert it into electricity.
2. Controller, which will monitor the charge level in the device. When the batteries are charged, this device automatically turns off charging, and when the charge level drops, the controller will work again.
3. Battery, which is needed to collect the generated energy.
4. Inverter– this device creates the required voltage for the network, receiving electricity from the battery and converting it to 220 V.

Fuses must be installed between all network participants in order to avoid short circuits and damage to one of the devices.

If you plan to use one solar panel, then everything is clear.

When installing two or more, first you need to choose one of the following schemes for connecting solar panels in a country house or apartment:

• Parallel. This method of laying panels occurs by connecting terminals of the same name. The voltage does not change and remains at the same level.
• Consistent. In such a circuit, the plus of one of the photocells is connected to the minus of the other. Making such a connection is quite simple, but the output will be 24 V.
• Mixed. Such a system consists of several groups. Elements within a group are connected in parallel, and the outer panels of the groups are connected to each other in series.

The latest parallel-serial scheme for connecting solar panels is optimal in order to save on purchasing a controller, since such a scheme will not require a powerful device. In such a system, a balance is created between the high voltages that arise from a series connection and the high currents of a parallel circuit.

Installation of the structure

First of all, you need to decide on the installation location - either directly on the roof, or using a frame made of special trusses as a stand. How to attach a flexible solar panel to the roof? It needs to be bolted to the profiles, which will save space and have an aesthetically attractive appearance.

If you decide to install panels on trusses, then you must:

1. Buy farms. Since they are sold as corners, you will need to assemble them yourself.
2. Connect the frame elements with bolts.
3. Decide on the installation location of the panels.
4. The solar panel is attached to the farm using a bolted connection. This should be done carefully so that any weather conditions cannot affect the strength of the structure.
5. The last stage is connecting all participants to the network: battery, accumulator, controller and inverter.

How to avoid common mistakes

When assembling and installing, pay attention to the following nuances:

1. There is no need to assemble it on a frame with a back wall made of beams, since the wood can swell and the structure becomes deformed. In addition, the beam makes it very heavy.
2. You cannot use plexiglass as a cover, as it overheats and due to this, the contacts between the panels become unusable, and the system itself may depressurize.
3. Connecting terminals are not the best option for combining panels with each other, since in case of repair it will be impossible to separate them - it is better to use connectors specially designed for this.

1. The panels must be thoroughly cleaned of snow, dirt and dust, as this significantly reduces the absorption of solar energy by the device.
2. Lush crowns of tall trees that prevent sunlight from reaching the battery will have to be thinned out. If the house is located in the shade of other buildings, then installing solar panels is only advisable only polycrystalline ones, and then the efficiency will be reduced.
3. Before you start assembling the panels, you need to make a small calculation. First you need to analyze how many kilowatts you need to get from the system per day. One panel is capable of generating 0.12 kW, so it may be that with low consumption their installation will pay for itself in 50 years, so it is not advisable. Depending on the required average daily norm, the number of panels is selected.
4. When installing solar panels with your own hands, it is better to orient the panels to the south, since during sunny hours the maximum amount of solar energy comes from this side.

Video

Watch our video for detailed instructions on how to assemble a solar battery.

We continue our topic on the construction of a home solar power plant. You can familiarize yourself with general information about the principles of calculation of 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 the protective devices that should be included in the solar power plant kit.

Manufacturing of photovoltaic modules

A standard photovoltaic module (panel) consists of three main elements.

1. Panel body.
2. Frame.
3. 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, some craftsmen do not welcome the presence of a back wall on the body of a homemade solar panel.

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 glass body can be glued to the aluminum corner without much effort. 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 other metal objects in this case 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, a Schottky diode was introduced into the circuit of a primitive solar controller, developed 10 years ago (protection against overnight 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 the shadow of a 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. You should also not neglect the protection of certain consumer groups (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:

1. Connecting the controller to the battery.
2. Connection to solar panel controller.
3. Connection to the controller of a group of DC consumers.
4. Connecting the inverter to batteries.
5. 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.

Any autonomous power supply system powered by solar energy includes several required elements: solar panels or batteries, an inverter, a charge and discharge controller and, of course, a battery. This is what we will talk about in our article today. As you know, solar panels are designed to obtain energy from solar radiation, but batteries for solar panels perform a different function. Their primary task is the accumulation of electricity and its subsequent release.

The main technical characteristic of a battery is its capacity. Using this indicator, you can determine the maximum operating time of the power supply system in autonomous mode. In addition to capacity, service life, the maximum number of charge-discharge cycles, operating temperature range and other indicators should be taken into account. The average battery life is 5-10 years. This figure depends on the type of battery and the conditions of its use.

Battery types

In solar energy, the most popular is the sealed lead-acid battery, produced using 2 different technologies:

1. Gelled Electrolite.
2. Absorptive Glass Mat.

Technology Gelled Electrolite began to be used in the late 50s. It consists of adding quaternary silicon oxide to the electrolyte, which promotes the transition of the electrolyte into a gel state. This method makes it possible to achieve absolute tightness of the battery, and the circulation of gases is carried out in the numerous pores of the jelly-like electrolyte. A big plus of gel batteries for solar panels produced using Gelled Electrolite technology is that there is no need to add water during the entire operation.

Technology Absorptive Glass Mat was developed in the 70s. It involves the use of a porous fiberglass separator filler. It is impregnated with electrolyte and thereby transferred to a liquid-free state. By dosing the amount of electrolyte, we ensure that only small pores are filled, since larger ones are intended for the free circulation of gases. AGM batteries also do not require additional maintenance.

Solar batteries produced using both the first and second technologies have both advantages and disadvantages. You can learn about them in more detail from tables 1 and 2.

Table 1. Benefits

Table 2. Disadvantages

Subtleties of connection

The first thing you need to decide before choosing a battery is the required capacity. As a rule, this value is selected taking into account the average daily electricity consumption, not forgetting the depth of discharge, which should be no more than 50-70%. The correct charge/discharge mode is the main condition that can extend the life of solar batteries. It should also be remembered that too high a charge current reduces the amount of electrolyte contained in the battery, which can lead to battery failure.

The most widespread are “solar” batteries with an operating voltage of 12 V. As a rule, they are used to assemble battery packs of the required voltage, for example 24 V, 48 V, etc. The main parameters of such a block:

• working capacity;
• charge current;
• discharge current.

If the batteries are connected parallel, That It is not the voltage that will be summed up, but the capacitance. The voltage in this case will remain unchanged. But before connecting batteries in parallel, it is necessary to equalize the voltage on them.

The next condition is the temperature regime. Almost all solar batteries can withstand both low and very high temperatures. But you should not abuse this, because an increase in battery temperature by 10°C leads to a 2-fold acceleration of all chemical processes. And during charging, the temperature difference between the environment and the battery is 10-15°C, this is explained by the process of oxygen recombination. Natural airflow of the battery will help solve this problem. Compliance with all rules is the key to long battery life, this should be remembered.

Using a solar battery, whose maximum generated current is approximately equal to the battery charging current, allows you to automatically charge the battery when there is light. In this case, you should provide some rules for connecting the solar panel to the battery. The diagram is shown in the figure below.

The first thing to consider is connecting the battery through a diode (in the diagram VD1). This method will help solve 2 problems at once:

1. In poor lighting conditions, the solar panel voltage may become lower than the battery voltage. Without a diode, this will cause the battery to discharge through the solar panel's internal resistance instead of charging.
2. The use of a diode eliminates the need to disconnect the solar battery from the battery at night.

In addition to the diode, it is recommended to connect a milliammeter in series to the solar battery. It allows you to determine how much current the solar energy battery consumes. This way you can easily find out whether the solar panel is working or not. If you plan to use the battery while charging or recharging it, take care to connect a buffer capacitor to the circuit (in diagram C1).

The article was prepared by Abdullina Regina

A short video about parallel and serial connection of batteries:

Or you just want to organize an independent power supply for the site, the first thing you need to do is select a suitable power plant and figure out its connection. Both the first and second points can raise many questions, especially for beginners in electrics. So that readers of “” can connect the panels to each other and connect them to the home network, we will next look at the most effective schemes for connecting solar panels to the controller, battery and network of a country house!

So, the first thing you should have an idea about is what the solar power plant kit consists of. The main elements of the system are represented by the following devices:

1. Solar batteries or as they are also called solar cells, panels or photovoltaic converters. They are needed to convert sunlight into electricity.
2. Solar panel controller. Monitors the charge and discharge of the battery. There are different types - On/Off, PWM, MPPT. The controllers are listed in order of increasing complexity and efficiency of charging algorithms. MPPT - allow you to achieve greater efficiency by finding the optimal voltage and current parameters to pump the maximum possible power into the batteries. This occurs based on an analysis of the current operating mode and the current-voltage characteristics of the solar panel. The main task of the controller is to monitor the battery charge in order to prevent overcharging or excessive discharge. In simple words, when the battery is fully charged or discharged, the battery is disconnected from the panel or load.
3. The battery is designed to store generated electricity.
4. Inverter - converts 12 Volts into 220 AC, necessary for the operation of household electrical appliances, lighting systems and household appliances.

We draw your attention to the fact that it is advisable to install fuses between all devices: controller, inverter, load and battery, which will protect the system during!

In its simplest form, the diagram for connecting solar panels to the controller, battery, inverter and load looks like this:

As you can see, there are no particular difficulties in connecting, the main thing is to observe the polarity and connect all the plugs to the correct connectors of the controller. In this version it is very difficult to confuse something. But if you decide to use electricity from the sun simultaneously with a stationary network, the diagram for connecting solar panels to the power grid at home should look like this:

Here we need to clarify: the reserved load is a boiler and, for example, a refrigerator. Non-redundant – household appliances, lights in the house, etc. The larger the battery capacity, the longer the redundant electrical appliances can operate in autonomous mode!

We figured out the diagram for connecting solar panels to the AC network. Now we need to consider an equally important part of the issue - the correct connection of the panels to each other.

If you have a ready-made solar panel, then you need to find out its output voltage and connect it to the controller, but they come in 12 and 24V and 12/24V. If your solar panel is designed to work with 12V batteries and controllers, you need to connect them directly. Sometimes you need to connect batteries in series to get the right voltage. Therefore, we will consider three main connection methods. The same recommendations for assembling a solar battery with your own hands from individual cells.