How are the solar panels

Olga Nagornyuk
11.09.2014

How are the solar panels arranged and working?

Nowadays, almost everyone can collect and get their own independent source of electricity based on solar batteries (in the scientific literature they are called photovoltaic panels).

Over time, the expensive equipment is compensated by the opportunity to receive free electricity. It is important that solar panels are an environmentally friendly source of energy. In recent years, prices for photovoltaic panels have fallen tenfold and they continue to decline, which indicates great prospects for their use.

In the classical form, such a source of electricity will consist of the following parts: directly, a solar battery (DC generator), a battery with a charge control device and an inverter that converts direct current into AC.

Solar panels consist of a set of solar cells (photovoltaic cells) that directly convert solar energy into electrical energy.

Most solar cells are made from silicon, which is quite expensive. This fact will determine the high cost of electrical energy, which is obtained by using solar panels.

Two types of photoelectric converters are common: made from monocrystalline and polycrystalline silicon. They differ in production technology. The first have an efficiency of up to 17.5%, and the second - 15%.

The most important technical parameter of the solar battery, which has a major impact on the efficiency of the entire installation, is its useful power. It is determined by the voltage and output current. These parameters depend on the intensity of sunlight falling on the battery.

Emf (electromotive force) of individual solar cells does not depend on their area and decreases when the battery is heated by the sun, by about 0.4% per gram. C. The output current depends on the intensity of solar radiation and the size of solar cells. The brighter the sunlight, the more current is generated by solar cells. Charging current and power output in cloudy weather is sharply reduced.This is due to the reduction of the current given by the battery.

If a battery illuminated by the sun is shorted to some kind of load with resistance Rh, then electric current I appears in the circuit, the value of which is determined by the quality of the photoelectric converter, the intensity of illumination and the load resistance. The power Pn that is released in the load is determined by the product Pn = InUn, where Un is the voltage at the battery terminals.

The highest power is released in the load with its optimal resistance Ropt, which corresponds to the highest efficiency (efficiency) of converting light energy into electrical energy. Each converter has its own value Ropt, which depends on the quality, size of the working surface and the degree of illumination.

The solar cell consists of individual solar cells that are connected in series and in parallel in order to increase the output parameters (current, voltage and power). When the elements are connected in series, the output voltage increases, while in parallel - the output current.In order to increase both the current and voltage combine these two methods of connection. In addition, with this method of connection, the failure of one of the solar cells does not result in the failure of the entire chain, i.e., it increases the reliability of the entire battery.

Thus, a solar battery consists of parallel-connected solar cells. The magnitude of the maximum possible current given by the battery is directly proportional to the number of parallel connected, and emf. - consistently included solar cells. So combining the connection types collect the battery with the required parameters.

Solar cells are shunted by diodes. Usually there are 4 of them, one for each ¼ of the battery. Diodes protect part of the battery from failure, which for some reason turned out to be darkened, that is, if at some point in time the light does not strike them. The battery at the same time temporarily generates 25% less output power than with normal sun illumination of the entire surface of the battery.

In the absence of diodes, these solar cells will overheat and fail,as they turn into current consumers for the time of darkening (batteries are discharged through solar cells), and when using diodes, they are shunted and current does not flow through them. Diodes should be low-impedance to reduce the voltage drop on them. For these purposes, Schottky diodes have recently been used.

The resulting electrical energy is accumulated in batteries, and then given to the load. Batteries - chemical current sources. Battery charge occurs when a potential is applied to it that is greater than the battery voltage.

The number of series and parallel connected solar cells must be such that the operating voltage supplied to the batteries, taking into account the voltage drop in the charging circuit, is slightly higher than the battery voltage, and the load current of the battery provides the required amount of charging current.

For example, to charge a 12 V lead battery, it is necessary to have a solar cell consisting of 36 cells.

In weak sunlight, the battery charge decreases and the battery gives electrical energy to the receiver, i.e.rechargeable batteries are constantly working in the mode of discharge and recharge.

This process is controlled by a special controller. When cyclic charge requires a constant voltage or constant current charge.

In good light conditions, the battery quickly charges up to 90% of its nominal capacity, and then with a lower charge rate to full capacity. Switching to a lower charge rate is made by the charger controller.

The most effective use of special batteries is gel (in the battery sulfuric acid is used as the electrolyte) and lead batteries, which are made according to AGM technology. These batteries do not need special installation conditions and do not require maintenance. The passport life of such batteries is 10–12 years with a discharge depth of no more than 20%. Batteries should never be discharged below this value, otherwise their lifespan will be drastically reduced!

The battery connects to the solar battery through a controller that controls its charge. When charging the battery at full capacity, a resistor is connected to the solar battery, which absorbs excess power.

In order to convert a DC voltage from a battery into an alternating voltage, which can be used to power most electrical consumers together with solar batteries, you can use special devices - inverters.

Without the use of an inverter from a solar battery, it is possible to power the power consumers operating at a constant voltage, incl. various portable equipment, energy-saving light sources, for example, the same LED lamps.


Take it to yourself, tell your friends!

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  • How are the solar panels

    How are the solar panels

    How are the solar panels

    How are the solar panels

    How are the solar panels

    How are the solar panels

    How are the solar panels

    How are the solar panels

    How are the solar panels

    How are the solar panels

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