Batteries for solar power plants
Solar panels are one of the popular sources of energy. They generate electricity during daylight hours, while its consumption actually occurs around the clock. To use electricity from sunlight without time limits, special type batteries are connected to the power plants. They can be called intermediaries, since the batteries transmit the received electrical power to the consumer.
Batteries allow the use of solar energy in a period when the sun is no longer shining. And also save excess energy and allow you to use it even at night.
Let us consider in more detail the features and advantages of the battery for solar panels.
Why should I use special batteries?
It would seem that you can not spend money on the purchase of a special battery, but use a car battery 180-250 Ah. This power is, in fact, sufficient to power the house. But car batteries require operation in other conditions, and the discharge of only 30% is critical for them. At the same time, the batteries are capable of producing high inrush current, which is necessary to start the motor of the machine. But when operating in a private house, this is not useful.
The operating mode of the battery in a car is distinguishable from that in solar stations. During the day, the controller charges the battery, and after sunset it acts as a power source. A car battery will last no more than a year under such conditions, therefore it is not worth saving: it is better to immediately buy a specialized battery.
Solar battery must meet the following conditions:
Devices must be designed for many full charge / discharge cycles.
Low-maintenance or maintenance-free batteries are preferred. Perform inspection, verification of parameters and performance is always obtained;
It is recommended to purchase battery models with a small self-discharge current;
Devices must be resistant to negative external influences, including temperature extremes.
Batteries should have optimal weight and dimensions in a particular case. This is especially important if batteries are purchased to power the system. In this case, several batteries are used, and for their installation you will need to allocate space.
What you need to remember when choosing a battery
Battery for solar panels are multifunctional devices that solve certain problems. There are many different types of models, but in order not to be mistaken, you need to follow the rules of choice.
The most important are the electrical parameters of the batteries, which are relevant to the operating conditions. If the batteries are selected correctly, the solar power station will operate reliably and for a long time. If the parameters do not meet the specified conditions, the capacity will gradually fall.
So what to consider.
To calculate the required capacity you need to consider a number of factors:
– t battery operation. The factory parameters of the capacitance are indicated for an environmental t of 20 ° С, with smaller and larger values the indicator will also change. For example, at 0 ° C the capacity drops to 80%. This can be seen more clearly in the table:
T, 0 C -10 0 +10 +20 +25 +30 + 45
Capacity factor 0.65 0.80 0.95 1.0 1.03 1.06 1.15
The coefficient of capacity must be multiplied by the capacity of the battery to find out the real indicator, depending on t of the environment. Batteries should be stored in a heated environment.
Level of possible permissible discharge.
Allow 100% battery discharge is unacceptable. Devices will fail very soon. Residual current indicators – about 60-70% or more. The higher the indicator, the longer the battery will last.
What is planned to connect to the station.
Currently, solar energy sources are mainly used in everyday life for powering refrigerators, computers and lighting. Vacuum cleaners, dishwashers and other powerful devices are not connected to them.
Current converters differ in performance, but not more than 96%. Those. 4% will be a loss. Connecting LED lighting directly to a 12V network reduces these losses.
The use of different approaches to energy saving affects indicators:
Consumers Quantity Power, W / h Operating time daily, in hours Power consumed per day, W
Notebook 1 200 2 400
Electric lamps 10 20 5 1000
Computer 1 200 2 400
TV 1 200 2 400
Refrigerator 1 150 24 3600
Now we make an elementary calculation:
– recalculate the power in amperes – 6000/12 = 500 A;
– we divide this number by the coefficient of use for a certain t (for example, 25 C) – 500 / 1,03 = 515 A;
– divide this number by the percentage of battery discharge: 500 / 0.3 = 1716 A;
– divide the final number by the inverter efficiency: 585.73 A / 0.96 = 1787 A.
It turns out that to obtain 6 kW a battery with a minimum capacity of 1787 A / h is required daily.
Types of batteries for solar panels
The main task of the battery is energy storage. When a need arises, the node distributes energy. Modes of operation may be different:
energy storage during daylight hours and nighttime return either
at peak load;
increasing the functionality of lighting equipment, if the sun does not shine a little, and solar panels cannot provide it with power in full, etc.
Batteries are considered a kind of dead end in improving alternative energy, but thanks to modern technologies, devices have become lighter, smaller and more affordable. The following main types of batteries are used in solar power supply:
The main difference is the state of aggregation of the electrolyte.
Acidic ones are traditional devices with a plastic case divided into compartments filled with liquid electrolyte. Electrodes are immersed in it.
A popular variety is OPzS batteries. The models have a feature – plates that differ in shape. The positive electrode is a tube, and the negative is made in a flattened form. There are also transparent areas made of styrene-acrylonitrile, allowing you to track the level of electrolyte. Also in the design there are ceramic filters that prevent the rapid evaporation of sulfuric acid. OPzS rechargeable batteries are characterized by a long operating period of up to 20 years. Maintenance is minimal – you only need to add water about 1 time per year. The number of charge / discharge cycles can reach 1800, while the self-discharge rate is low.
VRLA is another type of acid battery called sealed valve-recombination. There are various capacities from 300 to 4000 Ah. The peculiarity of these models is that there is no need to add water during operation, as well as the absence of gas emission. Maintenance will only consist of visual inspection, periodic cleaning and voltage monitoring. The electrolysis products are recombined and returned to the electrolyte.
In gel-type batteries, the electrolyte has a pasty consistency. They can be installed in any position (fiberglass separators in the batteries prevent electrolyte spreading). Gel batteries are more expensive, resistant to deep discharges, can be used in cold weather, but at minus temperatures, starting currents will be low. Devices are resistant to damage and even with small defects in the case continue to work.
Less popular are lithium, nickel-cadmium, alkaline batteries.
Siap.by is an official dealer of the Polish manufacturer S.I.A.P. Sp. z o.o in Belarus. We offer brand products on the best conditions: with an official guarantee, all accompanying documentation and at a fixed cost. A wide range of lead-acid and gel batteries allows you to choose the right model for any type of solar power plant. Call me!