How is Solar Energy Stored?

Solar energy has proven to be an effective solution for the use of renewable energies, becoming an option that is increasingly adaptable to various energy storage systems. But when we talk about these systems, we don’t just mean solar panels. We also refer to solar batteries.

In October 2014, a group of biochemists from the University of Ohio would have solved the loss of electrical energy caused by electrons traveling from a solar cell to a battery, allowing them to create a system capable of storing 100 percent of solar energy in a battery, a system known as a solar battery.


They are a system for retaining and distributing solar-generated electrical energy. They contain at least one pair of electrochemical cells, each with a negative and a positive electrode, designed to convert so-called chemical type energy – from solar radiation – into electrical energy.

These batteries work in tandem with solar panels, also known as solar modules, which are responsible for capturing photovoltaic solar energy and converting it to electrical energy. When solar panels collect more energy than they can provide at the same time, the excess is stored in solar batteries.

As a result, the batteries can be used as backup energy when the solar panels do not receive solar radiation – either due to cloud cover or at night – and thus do not generate electricity. Furthermore, solar batteries will provide more electrical energy, allowing for the use of more electrical equipment.


Solar batteries come in a wide range of sizes and shapes, with the main differences being the technology used in their production and, on the other hand, the type of cycle. They are distinguished by the following characteristics:

A. Batteries based on their cycle life

  • Low Cycle Batteries: When it comes to capturing energy, these batteries have been specifically designed for low-demanding routines. That is, they are ideal for supplying small amounts of energy for short periods of time. They do not tolerate high percentage discharges, specifically those greater than 80%, because they significantly reduce their useful life.
  • Deep cycle batteries: Unlike the previous type, deep cycle batteries have a high resistance to discharges of up to 80%. As a result, they are a cost-effective option that is in high demand.

B. In accordance with its technology

  • Liquid batteries: While they are not the most resistant to low temperatures, they are inexpensive and have an acceptable quality margin. Liquids are classified into two types: sealed and open. The sealed ones have valves that allow them to exchange liquids, whereas the open ones have a movable cover that allows them to do so.
  • AGM batteries: From the start, this model stands out for its high resistance, and as a result, its useful life is among the longest among its peers. It also has a deep cycle, so it can withstand high discharges. They contain glass fibers that absorb acid, and the majority of these models include a regulated valve. Because of these features, it is the most expensive model.
  • Lead-acid batteries: This model has the best quality-price ratio. In this regard, they offer a favorable yield of up to 80% – 95%, respectively. However, preventive maintenance is essential in order to extend their life. They must, in particular, be charged 100 percent after each cycle to prevent them from shutting down due to self-discharge.


It is critical to understand some aspects of battery quality and performance, as they will be critical in identifying the best solar batteries based on the needs identified:

A. Capacity to carry a load

It is the number of amps (A) that a battery can store as part of its power reserve. It is necessary to comprehend this aspect in order to select a solar battery with sufficient reserve to cover the required electrical energy backup.

B. Self-discharge proclivity

Many batteries discharge if they are not used frequently, and solar batteries are no exception. Higher quality models are less likely to have this issue; however, it is critical to evaluate this feature prior to purchase.

C. The load’s energy balance

The energy required to charge a battery is not exactly equal to its total reserve. Some batteries reserve less energy than is invested in their charge, resulting in a negative energy balance. Charging efficiency, as a factor to be evaluated at this point, should be as close to 100% as possible.

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