Using the energy of the sun is an alternative to non-renewable energy sources. Modern technologies allow the use of solar panels for street lighting, heating and lighting of small houses. Today, solar panels for summer cottages, which allow providing electricity to the household during the summer, are no longer rare.
Solar panels
The device, which is a large number of photovoltaic converters connected into a single system, is a solar battery.
For the solar battery, it is important to have direct sunlight, the energy of which is converted into electric current.
Batteries are installed in areas where sunny days make up most of the year. True, the latitude also affects the efficiency of solar panels. After all, the farther from the pole, the more powerful the sun's rays. But even in central Russia in winter, solar panels reduce the consumption of electricity from common networks, and in the summer there is an opportunity to even sell its surpluses.
Solar panels are single-crystal, polycrystalline and thin-film.
The crystals directed in different directions in polycrystalline batteries can reduce the dependence on direct sunlight. Such batteries are the most common today, they are used for lighting public buildings and private homes. Often already met and street lighting on a solar battery of precisely the polycrystalline type.
Solar panels for summer cottage
More recently, the main argument against installing solar panels in the country was their cost. Today, domestic products are starting to produce these products, their prices are getting lower, the choice is wider, and service is more affordable.
Modern technologies are quite capable of coping with the lighting of the site and ensure the operation of household appliances. True, this requires a rechargeable battery for the solar battery, as well as a charge controller and an inverter that converts direct current to alternating current.
Today you can buy a ready-made kit of solar mini-power plants for a summer house or a small house with autonomy for 24 hours. The power of such a power plant is 235 W with a battery power of 2.4 kW * h.
Batteries for solar panels
Rechargeable batteries are an important part of the equipment of a modern solar system.
On bright sunny days, solar panels produce significantly more electrical energy than electrical appliances consume, and at night, when lighting is especially important, they do not work at all. This means that it is necessary to accumulate and store electricity for its subsequent use.
The battery is for the solar panel and is designed for uniform and uninterrupted power supply.
Batteries also cover peak loads that are too large for photomodules, use the stored energy in the dark, and compensate for the difference between the generated and consumed energy in cloudy weather.
Battery Connection Methods
Most often, one battery is not enough for the full-fledged operation of the solar power station, and you have to use several batteries of the same type. Experts believe that they should generally be from the same batch.
To increase the total capacity of the system, three battery connection (switching) methods are used.
With a parallel connection, the capacities of all the batteries are added, and the total voltage is equal to the voltage in one device.
Serial connection, on the contrary, allows you to sum all the voltages, and the capacity remains equal to the capacity of one battery in the circuit.
The most productive is a combined series-parallel connection, in which both voltages and capacitances are summed.
True, with such a connection, the batteries are subject to unbalance, that is, the total voltage will be constant calculated, but for each individual battery its readings will change. This phenomenon leads to the fact that part of the batteries are undercharged, and part is charged above the norm, and the resource is produced prematurely.
Therefore, each solar system always includes a solar charge controller and jumpers, with which they connect the midpoints for self-leveling the voltage in the battery.
Features of batteries for solar systems
The solar battery must meet a number of requirements. It must withstand a large number of charge / discharge cycles. In this case, self-discharge should be minimal, and the magnitude of the charging current should be large, and the range of operating temperatures wide.
Today, manufacturers already produce special batteries, the so-called solar batteries, which fully meet these requirements.
A set of solar panels with such devices and a charge controller allows you to accumulate energy and store it with maximum efficiency. And the network inverter is to convert it to connect household appliances and lighting.
Criterias of choice
Choosing a battery for solar panels for the home you need in several ways.
The most important of these is capacity. Based on the required energy consumption, the calculated capacity indicator is calculated, it increases by 35-50%, and one or several devices for parallel connection are selected according to it. A battery with sufficient capacity holds energy for up to 4 days.
Duration of discharge and charging. Of the two devices with the same capacity rating, one that requires a shorter time interval for charging is preferable.
The capacity of a lead battery depends on the mass of lead in it, so the larger the mass of the battery, the higher its actual capacity. When choosing, you need to pay attention to the weight and dimensions of the device.
Manufacturers set the range of operating temperatures and frequency of service for their products, these indicators should also be paid attention to.
The accompanying documents always indicate the period of use of the battery, the number of discharge cycles (the higher this indicator, all other things being equal, the better) and the value of self-discharge per month.
When calculating the parameters of the battery, it is necessary to take into account the energy loss during its storage and conversion. The efficiency of modern devices for solar systems is approximately 85%.
Types of batteries for solar panels
Familiar car batteries are not designed for a large number of cycles and are characterized by significant self-discharge. For solar stations, completely different devices are used.
1. AGM-batteries, in the construction of which an electrolyte is in a bound state between absorbent glass mat. Such a device can be operated in any position, at a low price and a charge depth of about 80% withstand up to 500 cycles and are characterized by a high level of charge.
The term of operation is not so long - 5 years, and the operating temperature range is limited to 15-25 ° C, but they charge quickly - it takes less than 8 hours to fully recover, can be transported in a charged state and operated in a room with insufficient ventilation.
AGM-batteries quickly fail due to overcharging, but undercharging tolerate quite satisfactorily.
2. The gel battery for the solar battery can also work in any position. A gel-like gel electrolyte is held in the pores of silica gel, which serves as a separator for the plates. The undeniable advantage of this design is that the electrodes do not crumble, because all the free space is filled with gel, which means that the possibility of a short circuit is excluded. In addition, they withstand complete discharge and a significant number of cycles, about one and a half times more than that of similar AGM batteries. But their price is much higher.
Despite the price, gel batteries are more economical, do not need maintenance, can be in a completely discharged state without damage for several days, energy losses in them are insignificant due to small self-discharge.
3. OPzS batteries, the so-called maintenance-free liquid electrolyte filling devices, are designed specifically for low current discharge. They withstand a very large number of deep cycles, are used, as a rule, in powerful expensive solar systems, and they themselves are quite expensive.
Solar charge controller
Electronic devices are designed to control and adjust the level of charge on the battery. They protect the battery both from complete discharge and from overcharging.
Charge controllers are very important elements of solar panels. They provide a multi-stage battery charge, automatic shutdown when the battery is fully charged and with a minimum charge - loads, connecting photomodules when the battery needs to be charged, and reconnecting the loads after charging.
The cheapest and most primitive type of On / Off controllers disconnects solar panels from the battery when the voltage reaches the limit value, preventing the batteries from fully charging and thereby reducing their life.
PWM controllers operating on PWM (pulse width modulation) technology, are economical and efficient in areas with high solar activity. They stop charging, while allowing the battery to fully charge. Such devices are installed in low-power, up to 2 kW, systems with a low-capacity battery.
MRI controllers control the maximum energy peaks. They are most effective in solar systems, but also much more expensive than devices of other models.
Solar Battery Manufacturers
There are not many manufacturers of this type of product on the Russian market.
CSB Battery Co., Ltd (Taiwan) offers lead-acid batteries manufactured using AGM technology, with a service life of up to 10 years, rated for 12 V, with a capacity of 26 to 100 Ah * at a price of 2.6 to 8 , 2 thousand rubles.
Approximately the same batteries are manufactured by Shandong Sacred Sun Power Sources Co., Ltd (China).
HAZE Battery Company Ltd (Great Britain) supplies gel batteries with a service life of up to 12 years, an operating voltage of 12 V, a capacity of 15 to 230 A * h and a temperature range from -20 to +50 ° C at prices from 7 to 28 thousand rubles .
SSKGroup (Russia-Belgium) produces reliable gel batteries for solar cells with a flame arrester with a service life of 15 years, a capacity of 100 to 180 Ah * at prices from 11 to 19 thousand rubles.
Solar manufacturers
The main manufacturers of solar panels for a long time were Japan, Germany, the USA and China. Russian solar panels are assembled from materials produced in these countries. The most popular domestic solar panels at an affordable price are made of polycrystalline silicon produced in Germany and the USA.
Today, Russian manufacturers not only produce solar modules, but also develop new ones, such as Kvant in Moscow.
Krasnodar company "Solar Wind" produces not only modules, but also finished home heliostations. Designs finished solar systems and SolarInTech from Zelenograd.
In the domestic market, more and more equipment for solar systems, including ready-made standard designs. But with some engineering skills and perseverance, you can independently calculate the system for specific operating conditions and select the necessary equipment: solar panels, batteries, controllers from different manufacturers in a wide price range. At the same time, you can save on some components by assembling them yourself from improvised materials, for example, a controller.