Photovoltaic installations are increasingly complemented by energy storage. Energy storage is a battery that stores excess electricity for use when demand increases and production decreases, e.g. in the evenings or on cloudy days. A PV installation with an energy storage (so-called grid-off) allows you to create a fully sufficient power system independent of the electrical grid. What is a photovoltaic battery? What are its types? How much energy can it store? And will it really pay off for you to buy one? You will find answers to these and other questions about PV batteries in the article below.
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What is a PV battery?
A photovoltaic battery is a type of battery adapted to be charged with energy produced by photovoltaic panels and to later use the stored current to power home electrical devices. A photovoltaic battery works in a charging and downloading cycle. It is an optional component - it extends the functionality of the system, bringing more benefits to the prosumer, but is not a necessary element for operation
Is it worth buying a photovoltaic battery?
In the net-billing system, the surplus energy produced by photovoltaics is standardly
sold to the electricity grid. However, there are situations when the demand for electricity exceeds production, e.g. at night, during periods of increased use of devices, etc. The prosumer will then have to supplement the energy shortage, i.e. buy it from the distributor, and the conditions will not necessarily be favorable for him (prices are set by the President of the Energy Regulatory Office). Thanks to the use of a battery in the PV installation, the surplus of energy produced will not automatically go to the external electricity grid, but will be stored. Many prosumers achieve complete energy independence in this way.
When does a photovoltaic battery pay off?
To determine the profitability of purchasing a photovoltaic battery, you need to determine how much excess energy your photovoltaic installation produces or will produce daily. To do this, you need to subtract the amount of electricity used by your home electrical appliances from the amount of energy produced by the PV installation.
The price of the PV battery is also important for the profitability of the investment. The price of a photovoltaic battery is influenced by various factors, in particular its:
- capacity (kWh) – the larger the capacity, the higher the price,
- type – lithium-ion models are more expensive than traditional lead-acid batteries,
- quality – for branded, high-performance solutions, equipped with modern technologies, you have to pay more.
Types of photovoltaic batteries
Due to the technology used, there are three main types of photovoltaic batteries:
- lead-acid batteries – the most classic and cheapest, but large, heavy, sensitive to half-discharge and not very ecological due to the lead content;
- AGM batteries - constructed of glass fiber mats with lead plates, they are characterized by high efficiency, large energy storage capabilities and effective heat dissipation, their disadvantage is a relatively short service life;
- Gel batteries – are the most expensive solution, but they are resistant to deep discharge and have a very long service life.
The choice of the type of photovoltaic battery should be made based on the individual needs and preferences of the prosumer and the requirements of the PV installation.
Which photovoltaic battery should I choose?
When choosing a photovoltaic battery, pay attention to:
- maximum capacity - determines the amount of energy that can be stored, it should not exceed the value of the PV panel current multiplied by 10 or the total power of the cells;
- service life – given by manufacturers in the number of charge/discharge cycles without loss of performance;
- voltage – should correspond to the voltage of the given photovoltaic installation (12V or 24V);
- technology – you can choose from acid, lithium-ion and lead-acid batteries;
- protection systems - the battery should provide protection against short circuit, overheating and excessive discharge.
Investors who are just planning to install photovoltaics may consider purchasing a photovoltaic kit complete with a compatible, optimally matched PV battery.
How much energy can be stored in PV batteries?
The amount of energy that can be stored in a photovoltaic battery is determined by its capacity , expressed in kilowatt-hours (kWh). The battery should be able to meet the demand for electricity during periods when the PV installation does not produce enough electricity (e.g. at night or on cloudy days).
It is assumed that 1 to 1.5 kWh of capacity should be allocated to 1 watt of peak photovoltaic power (kWp). For example, a 6 kWp photovoltaic installation can be retrofitted with a 6-9 kWh photovoltaic battery.
We encourage professionals from the renewable energy sector and private investors to familiarize themselves with the assortment of the Onninen wholesaler. Photovoltaics and energy storage are one of the key sections of our offer. Technical and commercial specialists are available to advise.
Check out the energy storage facilities at the Onninen wholesaler