Why does solar power system need solar system batteries?



Both wind and solar non-grid-connected power generation systems require solar system batteries. This is because these two power generation methods are affected by changes in natural conditions, and are intermittent and uncontrollable. Small-scale wind energy and solar energy non-grid-connected power generation systems generally use lead-acid batteries as energy storage devices for lead storage. This article will illustrates the components of solar power system, point out the importance of the solar system batteries it needs and summarize the advantages for VRLA battery of its application.

on-grid solar system

Solar power system

The solar power system is composed of solar system batteries packs, solar controllers, and batteries (groups). If you want the output power of the solar power system to be AC 220V or 110V, you also need to configure an inverter. The effective core of the solar system is the solar battery system, which is responsible for storing all the reserve energy that the solar panel can use throughout the day. Batteries can store excess energy and use the reserve when there is not enough sunlight to power the home system. There are different types of batteries available, but they all have the ability to store the required energy at any point in time.

Solar system batteries

The function of the battery is to store the electric energy generated by the solar panel when there is light, and then release it when needed. Solar system batteries are the application of the battery in solar photovoltaic power generation, and the lead-acid maintenance-free battery , ordinary lead-acid battery, gel batteries and alkaline nickel-cadmium batteries,  are the four widely used solar batteries. While lead-acid maintenance-free batteries and gel batteries are suitable for reliable solar power system due to their inherent maintenance-free characteristics and less pollution to the environment.

off-grid solar power system 1

Requirements of solar system batteries

Solar cell power generation system has high cost, low conversion efficiency and strong variation with the environment, so it has high requirements for energy storage link. The service life of solar photovoltaic power generation system is generally 20 years, and the supporting energy storage battery link is required to have the characteristics of long service life, stable performance, high energy efficiency and strong adaptability to the environment. Currently the most widely used are valve-regulated sealed lead storage batteries (VRLA) and gel-sealed lead storage batteries. These batteries have a variety of internal structures, and the capacity ranges from tens of million ampere hours to tens of thousands of ampere hours. They have gradually replaced traditional lead batteries.

solar battery 2

The main advantages of VRLA battery

The energy density of the battery is not too high 30-50whkg, but its power density is relatively high. At present, it has reached 200-300wks. The newly designed product can reach 500wkg. The combination of energy density and power density can meet the needs of various electrical equipment. The battery production process is mature and reliable, and the battery uniformity is good. This is the fundamental guarantee for the reliability and safety of the power supply system.

The battery has no memory effect and can be charged or discharged at any time. The maintenance work is relatively simple, the abuse resistance is relatively good, and the service life is relatively long. Its self-discharge rate can be said to be the lowest among all kinds of storage batteries. The monthly self-discharge under high temperature is less than 5% of the battery capacity.

solar battery 3

The price is cheap, which is unmatched by any kind of storage battery. Especially as a large-scale energy storage power source, its price and operating cost are often very critical factors for popularization and application. Lead-acid batteries are widely used as energy storage batteries in wind and solar power generation systems around the world.


In conclusion, as solar energy becomes cheaper and more widely used, the market potential for energy-storage devices grows. With cheaper solar system batteries and improving management and integration techniques, the storage sysem now is becoming more affordable.

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