How to connect solar panels in series or parallel. How to properly connect solar panels of different power (pv modules) - uninterruptible power supply - catalog of articles - vega - professional equipment

Connection solar panels shouldn't cause any difficulties. There is nothing extraordinary in this procedure. But since every now and then I continue to receive questions about the solar panel connection diagram, I decided to write this article and provide illustrations to solve these questions once and for all.

From school physics we know the concepts of serial, parallel and series-parallel (or mixed) connections. There is nothing in solar panels that would take their connection beyond the concepts of school physics. I understand perfectly well that people ask these questions not because they do not know what a serial or parallel connection is. They know. They are “scared” by a new subject of consideration - solar panels.

So, I’ll say it again: there is nothing like that in solar panels. This is just the same device made up of solar modules as all the others, which means that the connection diagrams for a group of modules into batteries are carried out according to the same principles. After what I have said, you will exclaim: “That’s the point! And I was thinking!”, and there is, as it were, no need to continue the article.

However, I will continue to remove any doubts, plus you will get useful information along the way. practical information. I have greater sympathy for those who, without fear of seeming stupid, ask questions. This helps them move forward rather than seem smart and stand still.

Three connection scheme options

As we said above, there are three options for connecting solar modules into solar panels. Let's look at the first of them - the parallel connection option (Fig. 1):

Figure 1.

In this option, we connect the (+) terminal of one module to the (+) terminal of the second module, and also connect the (-) terminals of both modules. From the terminal (+) and terminal (-) of any of the modules we bring out the ends (cores) to connect the resulting group (battery) of two modules for connection to, for example, a charge controller, if it is provided in our solar power plant or to rechargeable batteries, in case a battery charge controller is not provided.

If there is a need to connect three modules into a single battery, we do the same. We connect all three terminals (+), then all three terminals (-) and also bring out the ends from the terminals (+) and from the terminals (-). It doesn’t matter how many batteries you have to connect, everything repeats exactly the same.

Option two. Serial connection (Fig. 2):

Figure 2.

In this case, connect the (+) terminal of the first module to the (-) terminal of the second module. From the (-) terminal of the first module and from the (+) terminal of the second module we bring out the ends for connection to the charge controller or batteries. It also doesn’t matter how many modules you connect, the principle is the same. The (+) terminal of the first to the (-) terminal of the second, the (+) terminal of the second to the (-) terminal of the third, the (+) terminal of the third to the (-) terminal of the fourth, etc., exactly as many modules as you need to connect.

Well, the third option. Series-parallel (Fig. 3):

Figure 3.

Indeed, sometimes you have to resort to this connection option. For ease of understanding, you first assemble two groups of modules in parallel; in the figure, the upper left and lower left are the first group. Upper right and lower right are the second group. After this, connect these two groups in series as if they were not groups, but two modules. A group may have not two modules, but three or four, and there may also be three, four or more such groups.

In practice it looks like this. This is what the solar module looks like from the front side, i.e. from its working surface:

This is its back side with the terminal box located on it. This is where the cable cores should be connected to the terminals:

This is its back side with the terminal box located on it. This is where the cable cores should be connected to the terminals:

This is the terminal box itself with the connected cable cores. Please note that the cable cores are either crimped with a ring tip, or, as in my case, tinned with solder:

And these are crimped cable cores intended for connection in terminal clamps already under the roof of the house:

The third core is my backup. So far it has not been used, and therefore has not been pressed.

What is the need to connect modules according to different circuits?

Look. We know that we need the power of a solar power plant of 160 W, and the devices, charge controller, and inverter need a 12 V input voltage. We purchase two 12-volt solar modules, each 80 W and connect them how? Right. Parallel. Thus, we provide a circuit voltage of 12 V and the total power of the modules will be 160 W.

That is, we used the first parallel circuit connections. If we needed a power of 240 W and a voltage of 12 V, we would again resort to the first scheme, only there would already be three modules.

There are times when there is a need to assemble a circuit not for 12 V, but for 24 V, 36 V and higher. What is this for? The fact is that the more modules we install, the greater the total power of solar modules. This in turn leads to an increase in currents in the circuits. We remember Ohm's law.

Power divided by voltage equals current. We increase the power, the voltage remains the same, which means the current increases. An increase in current forces us to increase the cross-section of the wire. So imagine, the number of modules increases, which means the area covered by them increases, and therefore the length of the wires increases.

Don’t forget about the recommendation I gave about switching solar modules under the roof of a house in the article. And we also need to increase the cross-section of these wires. That is, an inevitable increase in the cost of wires follows. To avoid extra costs and rebuild the system to be more high voltage.

This can be achieved by connecting the modules in series. Let's assume that Figure 2 shows two 12-volt modules. Thanks to the serial connection scheme, we have achieved that they can be included in a 24-volt circuit. As for the mixed connection, it is necessary when both tasks have to be solved simultaneously.

Conclusion

When using different options schemes, you should keep in mind some important things that affect the resulting electrical characteristics, resulting from switching modules into solar panels.

This is important!

So, for example, in the previous article we said that when serial connection the voltage of the connected modules is summed up. If you connect two 12-volt modules, the resulting voltage will be 24 volts. Now I do not take into account such concepts as open circuit voltage, current short circuit etc., so as not to fool you with theory.

But we didn’t talk about what will happen to the currents, but this is important for you when choosing, for example, a solar charge controller. What input current controller should you choose?

So, you need to know: in a series circuit, the resulting current will be equal to the current of the module with its lowest value, i.e., the smallest current of all modules connected in series. That is why it is recommended to connect modules with the same characteristics in series, so that because of one “weak” module you do not lose the power that the modules could provide if they were all the same.

With a parallel connection, we said the resulting voltage will be equal to the voltage of one module, no matter how many of them you connect in parallel. But the resulting current will be the sum of the currents of all modules connected in parallel.

So that a mixed (or series-parallel) connection does not cause you any difficulties, feel free, figuratively of course, to split the entire group into smaller ones and, having found out the current and voltage of each small group separately, consider these small groups as a separate module.

As you can see, there is nothing super abstruse in the solar panel connection diagram. It's simple. By the way, the same connection principle applies to rechargeable batteries, but this is already separate song. There are some nuances there.

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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 rates:

• 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 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 completely battery life a power plant requires 7-8 times more panels in winter 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 via wholesale price, which 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 doubtful: film panels in to a greater extent subject 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

Batteries generate during operation D.C. up to 40 V. 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. Required equipment selected according to the parameters of 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 - automatic " smart home"; 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 important role plays a large-scale application energy saving technologies— recuperators and heat pumps.

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.

Connecting solar panels different power- how to do it correctly? - By the way, there is a gift waiting for you below!
Very often, when expanding a system with solar panels, the question arises: how to connect solar panels of different power and different voltages - in series or in parallel?
Let's look at the solution to this problem using a specific example.
Let's say you already have a system with ,

to which the only one is connected (operating voltage 20V and maximum current 5A). And you purchased another one (operating voltage 24V and output current 5.4A).
It must be remembered that panels can be connected in series until the total open circuit voltage of the panels reaches the maximum permissible input voltage of the controller (for this example- this is 75V, as indicated by the first digit in the name of the controller). In this case, you must ALWAYS take into account that the XX voltage is selected for the lowest temperatures in your region. This information is always provided in the solar panel reference documentation. We remind you that damage to the MPPT controller by high voltage is not a warranty case. Be careful when selecting equipment.

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Looking ahead, we will say that both methods of connecting panels are possible. But each of them has its own advantages and disadvantages. Let's look at an illustration to illustrate our example.


The figure shows both options for connecting panels.
As can be seen from the calculations below, in our case we will get more power by connecting solar panels in series, since in this case the voltage is added, and the maximum current of the system is limited by the module with a lower current. In this case, these values ​​are, respectively, 44V and 5A, and this results in output power about 220 W.
At parallel connection the calculation is done differently. Here the currents of the 2 panels are already summed up, and the maximum output voltage will be limited by the panel with the lower output voltage. In our case, it will be a solar battery with an output voltage of 20V, and the total array current will be 10.4A. Thus, maximum power system will be equal to 208 W, i.e. slightly less than in the case of series connection of solar panels. But this option for connecting panels also has its own advantage - if parallel connection the total output current of the panels will exceed the maximum input current of the MPPT controller, this will not lead to failure of the latter. The controller will simply limit the charging current to its maximum allowable level. In the controller from our example it is 15A (this is indicated by the second digit in the name).
Now, we hope you can properly evaluate options for expanding your system.

And one more necessary reminder related to safety rules: NEVER MAKE ANY CONNECTIONS TO A WORKING SYSTEM!!! Be sure to disconnect the battery and the panels themselves from the controller and, if necessary, from the load before connecting additional panels. Remember that when solar panels are connected in series, a life-threatening high voltage appears in the system!!!

How to make a solar battery with your own hands?

Now many summer residents, as well as people living in the private sector, are interested in installing solar panels. This really allows you to save on electricity. At least in the summer season, while we are often at the dacha, additional electricity will not hurt. In summer, solar radiation is intense and batteries are correct location can produce a lot. And for those who do not have electricity in their area, a solar battery can become the only source of current. The trouble is that solar panels are quite expensive (one 18 volt panel, 40-50 watts will cost $300-500). But you can save money if you make them yourself. This article will talk about how to make a solar battery with your own hands. Below we will describe the manufacturing process, which combines experience from various materials and videos on YouTube.

To begin with, you need to decide what you will need in the work and how much it will cost.

• Photocells. On Aliexpress you can find photocells made of monocrystalline silicon with a power of 4.7 watts and a voltage of 0.5 volts. Ten pieces will cost 1200-1500 rubles. For an 18 volt panel you need 36 pieces. That is, we take 40 for about 5-6 thousand rubles;
• Plywood or plastic. Used as a substrate on which photocells will be attached. Cost (300─400 rub.);
• Aluminum or steel profile for the frame (400─500 RUR);
• Glass (500 rub.);
• Schottky diode (30─50 rub.);
• Fasteners, sealant, wires, flux, tires and other small items (500 RUR).

Now directly about the process itself.

First you need to sort the elements according to the voltage they produce. The rating that manufacturers indicate on their photocells is 0.5 volts. But this is in ideal conditions in the sun. When tested under normal conditions, the values ​​will be 0.2─0.35 volts. Your task is to form groups of elements that differ little in voltage. For example, the group 0.32─0.35 volts, 0.28─0.31 and so on.

This must be done because one element in the group, which has significantly lower voltage, will act as resistance. It will slow down the process of generating electricity.

Naturally, sorting makes sense when you have a lot of photovoltaic cells that will be used for different panels 36 pieces each to produce a final voltage of 18 volts. If you only have enough for one panel, then there is no point in sorting them, since you still need to install them all.

Preparation and soldering of busbars to photocells

Before making a solar battery, copper bars are soldered to the photocells. They are soldered onto special tracks that pass through the elements. It is best to use a tire with a width of 1.8 millimeters and a thickness of 0.16. The usual flux is used - rosin with alcohol. For convenience, it is better to use flux in the form of a pencil. The tire and flux can be found in stores selling radio-electronic components. All this will cost 100-150 rubles.

First you need to cut the pieces of tires to the length necessary to connect the two elements. Here, do not forget to take into account the distance between adjacent elements. That is, you need to figure out how they will be located on the panel.

A small amount of flux is applied to the photocell track. A busbar is placed on top and a soldering iron is passed over it. Don't press too hard. It is necessary to make an even seam without burrs so that they do not interfere with the assembly of the solar battery in the future. The busbars must be soldered to all photocells (36 pieces) for the solar battery. Do not forget to wipe the seam with alcohol after soldering. There remains a lot of flux, which is absolutely useless there. You can use cosmetic cotton swabs for this.

After this, soldering is performed to combine the photocells into a series chain. To do this, the busbars are soldered to the contact pads with reverse side element. Soldering areas are also wiped to remove flux residues.

The best option for a panel of 36 elements is to solder them in 4 rows of 9 elements. As a result, the solar battery itself will have an optimal area.

Connecting elements into a battery

The resulting 4 rows of connected elements need to be combined into a finished solar battery. To do this, they need to be laid out on glass and connected with thick copper bars. For this, it is better to use tires with a thickness of 5 millimeters. A Schottky diode is placed in the positive terminal gap. This is necessary in order to subsequently connect several solar panels in a parallel assembly without any problems. And do not worry that the current will flow back. A Schottky diode will provide protection against this. The elements should be positioned as they will be in the finished solar battery. That is, behind the glass the working side is towards the light. We do this according to the following scheme.

As for the substrate, it is better, of course, to use glass. Plexiglas and plexiglass are also suitable. A variety of plastics benefit in weight, strength and convenience. However, they can easily be “led” by permanent job in the sun. The solar battery heats up significantly, which leads to warping of the plastic. And this will inevitably lead to damage to the photocells.

Ideally, you need a material that absorbs the infrared spectrum of solar radiation and has a minimum refractive index. Mineral glass is best suited for this role, but it is quite expensive.

It is best to attach photocells to glass using self-adhesive film. You should choose one that is designed to work in atmospheric conditions. This option is the cheapest and easiest to implement. There are examples when solar panels are fixed between glass panes, and all seams are coated with sealant. This is also a working option, but it’s much more hassle. Some experts generally recommend sealing using an epoxy compound.

One of the most popular alternative ways Providing electricity to a home is an installation.

Their advantages are obvious:

1. They do not take up as much space as is needed to install a windmill.
2. They operate silently and do not cause any inconvenience to neighbors.

There are also disadvantages, the main ones being:

1. Solar panels are still not cheap.
2. Installing such a system requires special knowledge and skills.

If each of us individually cannot do anything with the first problem, then everyone can figure out the second one.

Selecting a location

The gap between the panels and the surface is required. When choosing a place to install solar panels, you must take into account the following features:

• geographical;
• private.

Solar panels need to be installed not just in illuminated places, but also at a specific angle. This is especially true for monocrystalline panels.

Please note: If you do not leave a gap between the roof and the panels for air circulation, the modules will overheat and burn out.

The angle of inclination is calculated using a special formula and depends on the latitude at which the house is located. If the formula is significantly simplified, the system for calculating the angle of inclination of the panels looks like this:

• for latitude up to 25° you need to multiply its value by 0.87;
• for latitude from 25 to 50° you need to multiply the value by 0.76 and add 3.1 degrees.

Private features include the conditions in which the house is located. The roof should not be shaded by trees or other buildings.

If this problem cannot be solved, then it is better to install the panels not on the roof, but on separate poles in the yard.

Installation stages

Installation of a solar panel system kit is carried out in several stages. They are listed below.

Keep in mind: The shorter the wires, the less energy is lost in them.

Nuances of fasteners

Frames for solar panels Before starting work, it is necessary to calculate the maximum permissible load for the roof.

To ensure proper placement of solar panels when installing them, you must adhere to the principles listed below.

1. The angle of inclination of the panels should not be chosen arbitrarily, but based on the geographical features of the location of the house. How to calculate the angle is written above in this article.
2. If the roof angle does not correspond to the one found in the calculations, then you can install the modules on separate structures in the yard.
3. The efficiency of the panels increases if their front sides are directed to the south.
4. In winter, the angle of inclination of the batteries should be increased by 14 degrees. In summer it needs to be reduced by the same amount.

Expert advice: To be able to adjust the angle of inclination of the modules, you can use special frames. They allow you to change the angle from 15 to 70 degrees. With these designs, batteries can be installed even on a soft roof.

Linking joint ventures with each other

SP connection diagram Problems associated with will not arise if they all must be located in the same plane.

But they will work differently if they are placed on different roof slopes. Those panels that receive more light will work more efficiently.

Power losses can be reduced by installing an individual controller on the batteries of each plane.

A controller is a device included in the kit that provides automatic operation charging and discharging.

In addition, installing cut-off diodes can help in this case. The diodes may be pre-installed by manufacturers, or they may be left with space for self-integration.

Connection diagram

SP connection diagram. (Click to enlarge) The solar battery connection diagram is as follows:

1. Direct current flows through the wire to the controller.
2. The DC current is distributed by the controller into two branches: one leads to battery To recharge it, the second powers devices that consume direct current.
3. Direct current flows from the battery to an inverter, which converts it to alternating current.
4. From inverter AC is sent to a distribution box, from where it is distributed throughout the house.

Keep in mind: Home energy supply can be made more efficient by adding additional sources electric current. This action, however, will complicate the device connection scheme.

As you can see, installing solar panels is not too difficult. It all comes down to fulfilling the following points:

• remove trees that cast shadows;
• correctly determine the angle of inclination of the panels;
• secure the panels to the roof (if necessary, use special adjustable frames);
• install the necessary devices in the house (inverter, collector, batteries);
• connect circuit elements with wires.

Please note: The cost of solar panel kits usually does not include the price of fittings, wiring, and fastenings.

If you are not sure that you can do such work, it is better to entrust the matter to professionals. After all, when incorrect connection You can not only get a lower power current, you can disable an expensive system.

Watch the video in which experienced specialists explain the nuances of installing solar panels: