What is a Deep Cycle Battery? (A Closer Look 2023)

what is deep cycle batteries

Most electric golf carts have deep-cycle batteries. These are considered the best golf cart batteries because of their higher depth of charge, thicker plates, and longer lifespan.

A deep-cycle battery is a crucial component in any off-grid or renewable energy system. Long-term power storage applications often use these batteries. This article aims to explain deep-cycle batteries, their types, uses, and charging methods.

What is a Deep Cycle Battery?

Battery deep cycle units are designed to be discharged to a greater extent, usually up to 50% or more of their capacity. These batteries provide continuous and reliable power. 

A deep cycle battery’s depth of discharge (DOD)is important because it determines how much capacity is used during a single discharge. When a battery is fully discharged, its DOD is 100%. These deep-cycle batteries can easily handle the deep discharge of 80%-100%. 

Monitoring the state of charge (SOC) of the battery is also important since it indicates its current capacity.

There are different types of deep-cycle batteries— each having its own advantages and disadvantages. Here are some common ones:

  • Flooded Lead-Acid
  • Gel and AGM 
  • Lithium-Ion

Deep Cycle vs. Starting Battery

The purpose of starting batteries, also called cranking batteries, is to provide a quick burst of energy to start an engine. These batteries have many thin plates, which provide a high current for a short time. These batteries are not designed to be deeply discharged and then recharged. It can damage the battery and shorten its lifespan if you do so.

On the other hand, deep-cycle batteries are designed to be charged and discharged repeatedly. These batteries have thicker plates, enabling them to provide steady energy over a longer period of time.

One of the main differences between deep-cycle batteries and starting batteries is their construction. A starting battery is designed to deliver a large amount of current for a short period of time. In contrast, a deep-cycle battery provides a lower amount of current for a longer duration.

Another difference between deep-cycle batteries and starting batteries is their state of charge. The state of charge of starting batteries must always remain high, while deep cycle batteries can be discharged to a lower charge without deteriorating.

How to Tell if a Battery is a Deep Cycle

The following ways can help you identify a deep-cycle battery:

  • Check the Label: Battery labels should indicate whether they are deep-cycle batteries. Look for terms like “deep cycle,” “marine,” or “recreational.”
  • Look at the Size: Deep cycle batteries tend to be larger and heavier than regular car batteries. Additionally, they have thicker inner plates that can withstand deep discharges.
  • Check the Amp-Hour Rating: The amp-hour rating indicates how much energy a battery can hold. Compared to regular car batteries, deep cycle batteries have a higher amp-hour rating.
  • Look for “Deep Cycle” Features: Deep cycle batteries usually have thick plates, reinforced posts, and special separators that improve performance.

Batteries labeled as “deep cycle” are not all the same. The capacity and lifespan of some batteries may be higher than those of others, so it is important to choose the right battery for your specific application.

Types of Deep Cycle Battery

A wide range of deep-cycle batteries is available on the market, each with its own unique characteristics and advantages. The following are the most common types of deep-cycle batteries:

Flooded Lead Acid Batteries

The most common deep-cycle battery type is the flooded lead acid battery. While affordable and reliable, they need regular maintenance to perform at their best. These batteries have a liquid electrolyte that can spill when tipped or damaged.

Sealed Lead Acid Batteries

The sealed lead acid battery is similar to the flooded lead acid battery but without the need for regular maintenance. The batteries in this category are commonly used in emergency lighting systems and uninterruptible power supplies (UPS).

Gel Batteries

Unlike liquid batteries, gel batteries use a gel electrolyte instead of a liquid electrolyte. The batteries are maintenance-free and last longer than flooded lead-acid batteries. A gel battery is commonly used in renewable energy systems and marine applications.

Absorbed Glass Mat (AGM) Batteries

An AGM battery is also a sealed lead acid battery but uses a fiberglass mat to absorb the electrolyte. As a result, they are more resistant to vibration and shock than other types of batteries. AGM batteries are commonly found in RVs, boats, and backup power systems.

Lithium Ion Batteries

Lithium-ion batteries are modern deep-cycle battery that offers several advantages over traditional lead acid batteries. Battery life is longer, lightweight, and can be discharged deeper without damage. However, they are also more expensive and require special charging devices.

What are Deep Cycle Batteries Used For

The deep-cycle battery is commonly used in applications that require a reliable and steady power source for a long time. The following are some common uses for deep-cycle batteries:

  • Solar and wind power systems
  • Golf carts and electric vehicles
  • Boats and marine applications
  • RVs and campers
  • Backup power systems for homes and businesses
  • Telecommunications and UPS systems

Deep Cycle Battery Lifespan

The lifespan of a deep cycle battery depends on several factors, including its type, depth of discharge, and charging method. Deep-cycle batteries can last between 4 and 10 years with proper maintenance and usage. Although lithium-ion batteries can last up to 15 years but are more expensive than lead-acid batteries.

How to Charge a Deep Cycle Battery

Charging a deep cycle battery correctly is essential to ensure its longevity and optimal performance. Different charging methods will be used depending on the battery type and charging system. Charge deep-cycle batteries using a charger that is specifically designed for them and follow the manufacturer’s instructions. Undercharging or overcharging a deep-cycle battery can significantly shorten its lifespan.

  • Choose the Right Charger: Select a charger specifically designed for deep-cycle batteries. Using a regular car battery charger can damage a deep-cycle battery.
  • Check the Voltage: Use a multimeter to test the battery’s voltage before charging. If the voltage is below 12 volts, you should use a trickle charger to slowly increase the voltage before using a regular charger.
  • Connect the Charger: Connect the charger according to the manufacturer’s instructions. Ensure you connect the positive (+) and negative (-) terminals correctly.
  • Set the Charge Rate: Select a charge rate that matches the battery’s specifications. To avoid damaging the battery, charge it at a slower rate.
  • Monitor the Charging Process: Monitor the charger while charging the battery. If the battery starts to get hot, stop the charging process and let the battery cool down before continuing.
  • Disconnect the Charger: Disconnect the charger once the battery is fully charged. It is important not to overcharge the battery since it can damage it and reduce its lifespan.

To properly charge a deep-cycle battery, follow the abovementioned steps. Failure to do so can damage the battery and reduced performance. 


The deep cycle battery plays an important role in off-grid and renewable energy systems and boats, RVs, and other mobile devices. The various types of batteries are designed to provide a reliable and steady power source over an extended period, and each has its own advantages and disadvantages. Investing in the right deep-cycle battery for your application and charging it correctly will ensure optimal performance and longevity.


Can a deep-cycle battery be used in a car?

Deep-cycle batteries can be used in cars but are not recommended as they cannot provide enough power to start the engine due to their design.

How do I know if my deep cycle battery needs to be charged?

Monitoring the state of charge (SOC) is essential to determine when a deep-cycle battery needs to be charged. A battery monitor or voltmeter can be used to measure the voltage and SOC of the battery.

Can I charge a deep-cycle battery with a regular charger?

Using a regular charger to charge a deep-cycle battery is not recommended, as it can cause damage to the battery. It is essential to use a charger specifically designed for deep-cycle batteries.

How often should I charge my deep cycle battery?

The frequency of charging a deep cycle battery will depend on the depth of discharge and the usage. It is recommended to recharge the battery once it reaches 50% depth of discharge or lower to prolong its lifespan.

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Van Douglas

Van Douglas is a seasoned golf enthusiast and skilled writer, delivering informative and engaging articles on his blog that capture the essence of the sport with expertise and passion.

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