What Is a Deep Cycle Battery?


Wondering what a deep cycle battery is and if one would be useful for you? 

Keep reading to learn exactly what a deep cycle battery is, the different types, and the best ways to utilize them. 

So, What Is a Deep Cycle Battery?

All batteries have a storage capacity, referring to how much electricity they can store when charged completely. A battery’s depth of discharge (DoD) refers to what percentage of stored electricity has been used. 

A deep cycle battery is a battery designed to provide power sustained over a long period of time and reliably runs until it’s discharged at 80% or more. However, it should be noted that most manufacturers recommend you don’t discharge below 45% to extend the life of the battery. 

Deep discharge is when 80-100% of a battery’s capacity is discharged. Deep cycle batteries have been designed to continuously handle these deep discharges.

To survive the stress of repeated cycles of deep discharging, both flooded lead-acid deep cycle batteries and sealed lead-acid deep cycle batteries have three specifically designed components: lead plates, an electrolyte solution, and a case. 

The lead plates are really thick and must be thick enough to handle the strong reaction and resist corrosion. The lead plate reacts with the electrolyte solution to create a current. 

The electrolyte solution is typically water and sulfuric acid. It allows for the movement of sulfuric acid ions to the lead plates. 

Lastly, a case holds the lead plates and electrolyte solution in a confined space. 

Lithium-ion batteries have a slightly different design — instead of using lead and an acidic electrolyte solution, lithium ions help create the current that allows for a deep DoD

What Is the Difference Between a Deep Cycle Battery and a Regular, Lead-Acid Battery?

Not all lead-acid batteries are built for deep cycling. A regular lead-acid battery is more common, and you have likely encountered them in vehicles. Deep cycle lead-acid batteries are often found in boats, golf carts, or recreational vehicles. 

Functionally, the batteries work similarly. A regular lead-acid battery uses lead dioxide plates, has a cathode and anode electrode, and sulfuric acid as the electrolyte. The sulfuric acid reacts with the lead plates to yield lead sulfate and hydrogen ions. The ions travel to the cathode and anode electrodes, creating a current. This reversible reaction then recharges the battery. 

However, this chemical reaction only provides a small burst of electricity, for example, to start a car engine. After the lead-acid battery starts the engine, the car is powered by the alternator. 

A deep cycle battery is built to provide electricity over long periods of time instead of a short burst of it. A deep cycle battery can be a lead-acid battery, but there are other types. A deep cycle lead-acid battery has much thicker plates than a regular lead-acid battery, which allows for deep depths of discharge. Further, the deep cycle type must be manually recharged. 

What Are the Different Types of Deep Cycle Batteries?

While these batteries all contain three main components, there are different designs to maximize functionality and efficiency. Let’s take a closer look at the types of deep cycle batteries and their differences:

  • Flooded Lead-Acid Batteries (FLA): FLA batteries are the oldest type and most affordable; however, they require a lot of maintenance and have the shortest lifespan. The lead plates are submerged in an electrolyte of sulfuric acid and water, and the electrolyte solution must be refilled regularly because of gases produced in the chemical reaction. They must be stored upright to avoid electrolyte leaks and in a vented area for the produced gases. 
  • Sealed Lead-Acid or Valve-Regulated: Sealed Lead-Acid (SLA) or valve-regulated (VR) provides a “seal” for the electrolyte compartment to prevent leaks, unlike the flooded lead-acid battery. They also don’t need to be refilled because they’re completely sealed, not losing water. There are two kinds of SLAs.
    • Absorbed Glass Mat (AGM) types have an absorbent glass mat between the lead plates to absorb the electrolyte to prevent spills. The mat also acts as a damper, making this battery resistant to vibrations and shock. It can also handle cold temperatures. 
    • Gel batteries house the electrolyte in a silica agent to make it a solid instead of a liquid. It is tolerant to heat and requires no ventilation for off-gassing – however, it can be irreparably damaged if overcharged. The gel is also a damper for this kind of SLA. 
  • Lithium-ion Batteries: Lithium-ion batteries are ones you’ve probably heard the most about. Current is generated when lithium ions move from the negative electrode plate to the positive electrode plate. 

There’s no lead or sulfuric acid here. They’re lightweight, can store a lot of energy, and maintain function in all kinds of environments. They recharge faster than other kinds of deep cycle batteries. 

EcoFlow portable power stations use LiFePO4, a type of lithium-ion battery known for longer life cycles, increased safety, more discharge capacity, and more.

Deep Cycle Battery Applications

EcoFlow’s solar generators are a great option for off-grid power applications. Each solar generator is built with a range of EcoFlow’s solar panels paired with one of EcoFlow’s portable power stations, a type of deep cycle battery. The solar panels capture sunlight and convert it into stored electricity in the portable power station. 

Before selecting your battery, you must understand what you want to be powered. Keep reading to learn about some common applications of deep cycle batteries. 

Off-Grid Living

When you want to camp or work off-grid in comfort, a deep cycle battery can provide the electricity you need, especially when not connected to the traditional grid source. EcoFlow’s RIVER 2 Pro 2 Portable Power Station can charge your 60W laptop 10 times, allowing for several days of off-grid living. 

Home Battery Backup 

When a widespread power outage happens, EcoFlow’s DELTA Pro and Home Backup Kit can keep your 120W refrigerator running for 1 to 2 days, recharge your 11Wh phone 313 times, or run a microwave for 2.5 hours. 

Outdoor Recreation 

You can use EcoFlow’s DELTA 2 Max portable power station for all your outdoor recreation needs. This deep cycle battery can power a projector for 25 hours, a 1000W coffee maker for 1.6 hours, or an 1150W electric grill for over an hour. 

Frequently Asked Questions

What Is the Purpose of a Deep Cycle Battery?

The purpose of deep cycle batteries is to provide longer-lasting power for multiple applications.  Since deep cycle batteries provide power over a long period of time, multiple hours, and even days, many users depend on them for many reasons, such as outdoor recreation, whole home backup, and off-grid living. 

What Is a Downside of Using Deep Cycle Batteries?

There are some drawbacks to using a deep cycle battery. Lead-acid deep cycle batteries require regular maintenance and aren’t as well suited for every environment. Lithium-ion deep cycle batteries overcome those hurdles, but they’re usually more expensive upfront yet worth it for long-term use. 

Final Thoughts

Whether you’re looking to power outdoor recreation, prepare your home backup power, or have options for off-grid living, EcoFlow’s portable power stations are well-suited to provide you with long-term, reliable power. These deep cycle batteries are easily recharged with an outlet, a car adaptor, or more sustainably with EoFlow’s solar generators

EcoFlow is a portable power and renewable energy solutions company. Since its founding in 2017, EcoFlow has provided peace-of-mind power to customers in over 85 markets through its DELTA and RIVER product lines of portable power stations and eco-friendly accessories.

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