The "deep cycle " in deep cycle batteries is an industry term that primarily characterizes deep discharge. In contrast to other batteries that are not recommended to be discharged beyond a specific capacity range, deep cycle batteries are capable of being discharged to most of their capacity.

Deep discharge means that the battery is almost completely depleted. The process of

discharging and charging is called a cycle . For example, if we discharge a battery to half its capacity and then recharge it, it is a cycle. But the more/deeper we discharge the battery and then recharge it, the deeper the cycle .

This process happens in deep cycle batteries, hence the name. The battery is slowly discharged until it is completely discharged and then recharged again for use.

What is a deep cycle battery?

Deep cycle batteries are designed for repeated and deep discharges. They are typically used in applications that require a constant and stable power supply, such as golf carts, forklifts and solar energy systems.

Deep-cycle batteries provide stable power over a longer period of time. This is important because other types of batteries discharge at high currents and provide only a small fraction of their capacity. In contrast to them, deep-cycle batteries discharge slowly and consistently up to about 80% of their capacity, so they run longer.

Usually, lead-acid batteries are manufactured as deep-cycle batteries. However, not all lead-acid batteries are deep-cycle . The batteries themselves mention this. They are sometimes referred to as marine batteries because they are widely used in marine vehicles.

Deep-cycle batteries differ from other types of batteries in several key ways.

First, they have thicker plates that can withstand repeated discharging and charging. Second, they have a higher capacity to store electricity. This means that they can provide a more consistent supply of electricity over a longer period of time than other types of batteries.

Deep-cycle batteries also typically have a shorter life than other types of batteries, but this is offset by their ability to be used more often. As a result, deep-cycle batteries are an important part of many commercial and industrial applications.

There are two main categories of deep-cycle batteries:

Fluid-rich deep-cycle batteries:

These are also known as wet lead-acid batteries. These batteries have a top above each cell containing distilled water. It requires continuous monitoring of the electrolyte level. If the electrolyte level is low, it must be refilled to maintain battery performance.

Maintenance-free batteries:

These batteries are often referred to as "Valve Regulated Lead Acid (VRLA)" batteries. Another name is "sealed lead acid (SLA)" batteries. They are sealed and do not require regular monitoring and electrolyte replenishment. As such, they are considered maintenance-free! Absorbent glass mat (AGM) and gel cellsare two popular subcategories of VRLA batteries.

Note: While deep cycle batteries are used for deep discharges, shallow discharges of up to 45% will help extend battery life.

What is the difference between a deep cycle and a regular battery?

Deep cycle batteries are different compared to other batteries. While regular batteries should never be discharged to their full capacity, these batteries are designed to discharge more deeply. Let's take a look at what allows them to provide such deep discharges and how they differ from regular batteries.

Take a car starting battery as an example. This is an ordinary battery. It delivers a sudden burst of current to the starter motor. But a deep-cycle battery releases a continuous current, so it can last longer.

However, there is another important feature. These batteries can be discharged up to 80%, whereas other batteries are never allowed to be discharged to 80%. If they did, ordinary batteries would lose active material through corrosion. Due to the way they are manufactured, deep-cycle batteries can solve this problem.

Deep-cycle batteries have thicker plates and denser active material . The diaphragms of deep cycle batteries are also thicker materials. This helps them resist corrosion to some extent and withstand repeated discharging and charging.

Note: Due to the thicker plates and diaphragms, deep cycle batteries are much heavier than regular batteries, which is considered a key limitation.

Deep cycle battery specifications

Here are some important specifications for deep cycle batteries. All of them are known for their 50% discharge level of AGM batteries.

Deep cycle batteries are perfect for applications that require a longer period of continuous power. Some of the prominent applications of deep cycle batteries are:

Powering marine trolling engines and navigational equipment

Powering sailboats that lack frequent charging facilities

Electric golf carts

Powering renewable energy applications Provide power, especially as solar and wind batteries

Electric wheelchairs

Power equipment at remote sites

Power traffic signals for uninterrupted operation

Off-grid storage systems for small buildings

Depth What is the life span of a cycling battery? How long does it last? The average lifespan of a

deep-cycle battery is 6 years. However, like all other batteries, deep cycle batteries will last longer if they are kept at low discharge levels.

This is almost comparable to the lifespan of other battery technologies. For example,

lithium batteries have a range of 3-10 years.

The average lead-acid battery has a lifespan of about 6 years.

AGM deep cycle batteries also have a service life of about 6 years.

The service life of GEL deep cycle battery is about 10 years.

When should I use a deep cycle battery? How to choose?

Whenever you need high current for a long period of time, deep cycle batteries are the best choice. Because deep cycle batteries have a very large electrode surface area compared to other technologies, they can be discharged for longer periods of time. Larger electrodes mean greater chemical activity. It also lasts a long time. Therefore, long-duration power needs are best addressed with deep-cycle batteries. Popular applications include trolling motors and golf carts.

When choosing a deep-cycle battery, weight and size become a serious issue in some applications. Because they use large electrodes, these batteries are relatively bulky . However, in recent years lithium-ion batteries have become available for deep cycle applications. Applications such as

RVs, lighting, etc. often prefer lightweight lithium-ion deep-cycle batteries . Additionally, fast charging speeds and long lifetimes make them the best choice. One limitation of lithium-ion batteries is that they are more expensive than regular deep-cycle batteries.

We can consider several factors to choose the best deep cycle battery for our purpose. Choosing the perfect battery for your application is important to ensure the best service and longer life.

Battery Weight

Weight is a serious issue for applications such as power boats and RVs. In these cases, continuous power is also mandatory, while frequent charging is impractical. The best option then is a lithium-ion deep-cycle battery.

Charging time

In the case of charging time, Lithium-ion deep-cycle batteries also dominate . The charging process for these batteries is easier compared to lead-acid batteries. Lead-acid batteries require multiple charging trials to fully charge, whereas Lithium-ion batteries can be fully charged in a single session. Lithium-ion batteries also do not require frequent maintenance.

Battery life

While deep-cycle batteries are used for deep discharges, the life of the battery still depends on the percentage of discharge. The deeper the discharge, the shorter the battery life. If battery life is the main issue, lithium-ion deep cycle batteries are fine. It can be used effectively for up to 10 years. However, power loss due to self-discharge is a major problem with these batteries.