Solar batteries are a key part of any solar system that ensures the storage of electricity produced for later use. How do solar batteries work and what battery to choose?
What is photovoltaic battery
Photovoltaic battery is a device used to store electricity produced by solar panels. Solar panels capture sunlight and convert it into electricity. This can be immediately used or stored in the battery. This ensures a continuous energy supply during the night or in case of cloudy weather. The advantage of a solar battery is that it allows efficient use of energy and reduces dependence on the public electricity grid.
Types of batteries for solar systems
There are several types of batteries that are used in solar systems. The most common are:
Lead batteries
Lead batteries are the oldest type of batteries. They are popular due to their low price and availability. These are divided into two types:
- Acid lead batteries AGM batteries have a lower life span as they are more prone to extreme temperature damage. However, they are relatively cheap.
- Gel lead batteries The solar gel batteries are an improved version of the classic lead batteries. Gel electrolytic layer ensures better stability and longer life.
Lithium-ion batteries
Lithium-ion batteries have excellent efficiency, longer life and higher performance than lead batteries. They are compact, light and have higher energy density. This means that they can store more energy in smaller areas. They are suitable for systems where solar batteries 12V, 24V solar batteries or 48V solar batteries are needed.
Soda batteries
Soda batteries are more affordable because sodium is cheaper than lithium. While less common than lithium-ion batteries, they have a lower environmental impact. The disadvantage of this type of battery is lower capacity.
Virtual batteries
Virtual batteries use the concept of energy distribution between several devices and systems. This means that instead of physical energy storage in physical batteries, unused energy is sent to the distribution network. If necessary, the owner of the virtual battery may then draw energy from the distribution network.
Read: Solar panels. How do they work, and what are their advantages?
How to proceed when selecting a solar battery
When selecting a solar battery, it is important to consider several key parameters:
1. Battery capacity and power
Battery capacity determines how much energy the battery can store. It is expressed in units Ah (ampérhour) or Wh (watt-hour). For domestic solar systems solar batteries 12V, 24V solar batteries and 48V solar batteries are most commonly used, with higher voltage means greater capacity and ability to deliver more power.
2. Battery lifetime
While lead batteries usually have a shorter life (about 3 to 5 years), lithium-ion batteries can last for 10 to 15 years. Longer life also means long-term return on investment. Solar batteries also show the so-called cycle life, i.e. the number of charging and discharge cycles that the battery can survive."
3. Depth of discharge (DoD)
The Depth of Discharge (DoD) is a parameter that determines which part of the battery capacity can be used without damaging it. Higher discharge depth means more efficient use of the battery. Lithium-ion batteries usually support a higher discharge depth (up to 80°00′90%), which means that their capacity is used at a higher level than for lead batteries (where the DoD is often around 50%).
4. Battery charging and discharge efficiency
This factor indicates how much energy is lost during charging and discharge. If the battery efficiency is, for example, 90%, out of 10 kWh of the energy delivered, 9 kWh is used successfully.
In the second part of the article, we will discuss the basic characteristics of the physical and virtual battery, which is a better choice and in what conditions.
