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What Is A Deep Cycle Battery? – Its Types, Maintenance & When To Use

Most people are aware of batteries that power their everyday lives and most of the time we think about the batteries when they don’t work. The main purpose of a battery is to store energy and give it off when needed. There are some significant differences in the working mechanism of different types of batteries and also each battery varies in case of effectiveness.

Choosing a battery type mainly depends on the usage of it, like for what purpose you’re planning to use that particular type of battery.

What Is A Deep Cycle Battery?

“A deep cycle battery is a lead-acid battery designed to give sustained power over a long period and are highly reliable to run until it is 80% discharged or more, at which point it needs to be recharged.”

They are also known as marathon runners in the world of batteries. In comparison to the other batteries, the deep cycle battery provides a lesser amount of power but for a much longer period.

It’s also referred to as a marine battery because these are designed to provide a steady supply of power for an extended period just like one used in marine vehicles.

When To Use A Deep Cycle Battery?

A deep cycle battery provides sustained energy that makes them ideal for different applications to ensure a quick start. Some of the major uses of deep cycle batteries are:

  • Marine applications
  • Golf Carts
  • Recreational vehicles
  • Off-grid renewable energy
  • Handling materials such as forklift

Some other kinds of batteries such as hybrid batteries can be used particularly for marine. But most of those batteries last for a shorter period as compared to deep cycle batteries.

Check out our guide about how to connect batteries

Types Of Deep Cycle Battery

The deep cycle is functional and applied to both lead-acid and lithium battery technologies. There are different types of deep cycle batteries available in the market and each differs in reference to its advantages and disadvantages.

Flooded Lead Acid Battery:

The oldest car battery type in use is flooded lead-acid battery. In these types of batteries, lead plates are submerged in an electrolyte mixture of water and sulfuric acid. A chemical reaction takes place during charging and discharging to produce gases that can be vented from the battery.

Almost 30 to 50% is the usable capacity of a flooded lead-acid battery. A flooded battery charges in different stages that is good to leave room for undercharging or overcharging. It has approximately 70 to 85% charging efficiency.

Though a flooded lead-acid battery is highly reliable, affordable, and tolerant of overcharging, it also requires proper ventilation and also requires extra maintenance. While the lifespan is also shorter in these batteries.

Gel Cell:

A gel cell battery is one of the VRLA batteries. It uses a gelled electrolyte typically formed from water and sulfuric acid suspended in a silica agent. The charging efficiency of a gel battery is almost between 85 to 90% with perfect heat tolerance and no off-gassing.

But this battery is intolerant of fast charging as the gelled electrolyte is very sensitive to overcharging. The damage to it is irreparable.

However, it is spill-proof, maintenance-free, and position insensitive with high tolerance to heat. But it costs more than flooded and AGM batteries and also requires a special regulator and charger.

Absorbent Glass Mat (AGM):

The AGM battery is also a type of VRLA (Valve Regulated Lead Acid) battery. It is short of absorbent glass mat that particularly refers to thin fiberglass mats placed between lead plates. The glass mat is capable of absorbing electrolytes by keeping them from spilling and moving while acting as a damper between the lead plates.

This damper helps to keep the battery safe from shock and vibrations while withstanding cold temperatures. These batteries have low internal resistance and charge way faster than flooded as well as gel cell batteries with a charging efficiency of 95%.

AGM battery has several advantages such as maintenance-free, durable, fast charging, and position insensitive. However, these are more expensive and highly sensitive to overcharging. That’s why they require a regulated charger.  


A lithium-ion battery is a relative newcomer as compared to lead-acid battery varieties. These batteries are 30% lighter in comparison to the flooded batteries with a usable capacity of 80 to 100%.

They have the fastest recharging rate as well as extremely long-life cycle around 2000 to 5000 charge cycles. It also offers constant voltage over any rate of discharge.

The lithium deep cycle batteries are compact, light in weight, maintenance-free, have amazing usable capacity, constant voltage, and the fastest recharging rate. But these are highly expensive and also require a battery maintenance system (BMS).

The Capacity Of Deep Cycle Battery

All deep cycle batteries differ from each other in order of their capacities. But the lithium batteries are capable of providing 100% rated capacity regardless of their rate of discharge.

Lead-acid batteries deliver less usable energy with a higher discharge rate. But in colder weather, both batteries can lose their capacity but these changes are less drastic in the case of lithium batteries.

The capacity of a lead-acid battery reduces up to 50% and the lithium battery faces only 10% of loss at 0 degrees centigrade.

The Lifespan Of A Deep Cycle Battery

Few factors can influence the lifespan of a deep cycle battery. A lead-acid battery is more affected by factors as compared to a lithium battery. Proper maintenance such as charging and discharging at a time can help in extending the lifespan of a deep cycle battery.

Overcharging, over-discharging, under-charging, and improper watering greatly impact the life of a lead-acid battery. Though lithium battery doesn’t require watering, so one issue can be eliminated.

Lithium batteries are not affected by partial or under-charging state but they can be damaged severely by over-discharge.

Heat also affects the life of a battery while high temperature degrades the battery much quicker.

Uses Of Deep Cycle Battery

Several items are requiring long term power output:

  • Electric scissor lifts
  • Electric floor cleaning machines
  • Navigational devices on a boat (when the main motor is inactive)
  • Electric golf carts
  • Electric scooters
  • Electric wheelchairs
  • Electric forklifts
  • Trolling motors on boats
  • Recreational Vehicles
  • Renewable Energy systems

Tips For Maintaining A Deep Cycle Battery

There are a number of tips you can follow to keep your deep cycle battery in optimal condition:

Let it Rest: Let the battery cool down for some time after continuous use in order to avoid grid corrosion.

Keep it Clean: Keep the battery and all of its covers free from dust and dirt. It will keep the battery safe from corrosion and any other damage to the terminals.

Check out our guide about how to clean the terminals of the battery

Keep it Charged: Keeping the battery charged even when not in use will prevent sulfation and also maintain the battery life. It’s better to charge them even if you’re not using them for a long period.

Monitor Charging Levels: Always start charging at 50% and never let the charge drop under 20%.

FAQs – Frequently Asked Questions

How long do deep cycle batteries last?

Deep cycle batteries last up to six years for the most part, with proper maintenance and care

In general, their lifespans are:

  • Lead-acid and AGM batteries: 6 years 
  • Gel batteries: 10 years
  • Lithium batteries: 3-10 years

Can a deep cycle battery be solar charged?

Of course, Yes. 

Any deep cycle battery can be charged with solar panels. But make sure to use a solar charge controller for deep cycle solar batteries to regulate the charge.

I am a passionate environment engineer, who has been in the solar, and inverter generator industry for years. I have been a part of multiple safety and environment-related courses such as IOSH, Fire Safety, Solid Waste Management, etc. I have been installing solar plants for residential purposes since 2018.

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