Deep Cycle Batteries & How They Work

Deep cycle batteries: what role do they play in solar systems? In today’s world of renewable energy deep cycle batteries are synonymous with solar. 

These batteries store energy, and this is where chemical reactions occur resulting in electricity. Deep cycle batteries are made to recharge and discharge numerous times, therefore, are not disposable, unlike single–use batteries.  

Battery backup is connected to the photovoltaic solar panels – these need single batteries or groups of deep cycle batteries to store solar energy (energy from the sun). The group of deep cycle batteries is referred to as a battery bank. 

During sunlight hours deep cycle batteries are recharged so that there is stored energy when there is low sunlight, on cloudy days and during night–time hours. This is the main reason why batteries are essential to solar power; they are vital for stand-alone as well as alternative energy tied to the grid, thus determining the DC power of a photovoltaic solar arrangement. 

Because deep cycle batteries can be charged and discharged, they are often referred to as being “secondary batteries”. Additionally, these batteries are called “secondary” because chemical reactions that produce and store electrical power on the lead plates are reversible (this is different to the way that standardised batteries operate that are disposable once the energy is depleted). 

A good example is a car that requires short bursts of energy; a deep cycle battery provides a continuous supply of power over a longer period. 

There are numerous deep cycle batteries such as gel batteries, lithium-ion batteries, flooded batteries and AGM batteries, although flood batteries are the most commonly used type. Gel batteries have a gel substance and the AGM batteries contain acid suspended in a glass mat separator. 

There has been an upsurge in the amount of lithium-ion batteries being installed in households that are opting for solar, although AGM and flood batteries are most often used for those wanting to go off the grid. 

These different types of deep cycle batteries are used in a variety of applications and are manufactured differently.