Wet Cell Battery: Everything You Should Know About It

Batteries are practical and widely used in all types of daily applications. They are perfect for energy backup systems, for powering up personal transportation vehicles, and even as car starter batteries. One of the first and most popular types of batteries is the lead-acid wet cell battery, also known as the flooded battery.

Similar to other batteries, the flooded battery is an energy block that uses a chemical process to get charged and store energy to be used later on. The lead-acid flooded battery was invented in the nineteenth century, but it has gone through many improvements to reach the efficient design that is found today on the market.

Since the wet cell deep cycle battery is cheaper and easier to produce, it is still widely used in modern days. The rechargeable wet cell battery has some limitations when compared to more modern batteries, but it also provides several benefits over the AGM, Gel, and lithium-ion batteries.

Here, you will find out everything you need to know about rechargeable wet cell batteries. We will dive into some questions and answers about battery types, you will learn what a wet cell battery is as well as how it works, its applications, its advantages and disadvantages, the differences between the dry cell battery and wet cell battery, and much more.

Wet Cell Battery Definition – What Is a Wet Cell Battery?

In simple terms, a flooded battery is an energy storage system using a liquid electrolyte like lead-acid mixed with water, but the wet cell battery is much more than this. To truly understand a flooded battery and the wet cell battery definition, we must first learn a little bit about its origin so we can understand and appreciate the modern lead-acid flooded cell battery.

The first attempt for an energy storage system was performed by Alessandro Volta when he invented the voltaic pile in 1800. This design was surpassed by John Frederic Daniell, with the Daniell cell in 1836. Inspired by the Daniell cell, Gaston Planté invented the first commercial design for a rechargeable lead-acid flooded cell battery in 1859. Even though the flooded battery was invented in the last millennium, archeological finds suggest that galvanic cells were used 2,000 years ago with the Baghdad Battery.

A wet cell battery is composed of two plates working as the anode and cathode, submerged in an electrolyte solution. Depending on the design, the plates can be made out of different materials like copper, zinc, nickel, or lead and lead oxide. The composition of the liquid electrolyte defines the chemical core of the battery. This requires a non-neutral pH solution like citrus juice or vinegar, but the lead-acid battery uses distilled water and sulfuric acid.

How Does a Wet Cell Battery Work?

Now that you know what a wet cell battery is, it is time to understand how a wet cell battery works. The wet cell battery, by definition, works similar to the AGM, Gel, or lithium-ion battery. The main difference is the chemical core and type of chemical reaction providing a stable current and voltage.

Each battery cell within the lead-acid deep cycle battery uses an electrolyte made from distilled water and a mixture of acids. For the anode, the battery uses a lead plate and a lead-oxide plate for the cathode.

When a load is connected to the flooded cell battery terminals, the lead and lead-oxide plates react with the electrolyte solution, causing a chemical reaction. The reaction produces an electricity flow through the terminals and, therefore, a current to the load. In this process, the sulfuric acid is removed from the electrolyte and reinforced onto the battery plates.

A similar process in the reverse direction occurs when the battery is recharged. In this case, the sulfuric acid in the plates breaks its bonds, allowing the acid to return from the plates to the electrolyte solution. With the chemical core in this charged state, the energy is stored to be used when a future load is connected.

What Is a Wet Cell Battery Used For?

Now that you know how a wet cell battery works, it’s time to learn what it is used for. There are different types of lead-acid wet cell batteries which we will explain later on, and each type of battery has several applications.

One of the most common uses for sealed lead-acid flooded batteries is to start vehicles. This includes, nowadays, starter batteries that provide high bursts of energy that are required to turn on cars and motorcycle engines. The lead-acid rechargeable battery is even used to power up boats, golf carts, RVs, and more. The first cell phones even had a wet cell phone battery installed.

Lead-acid flooded batteries are also used for backup energy storage systems in off-grid applications, especially in low-income countries.

What Are the Types of Wet Cell Batteries?

There are two types of wet cell batteries: the primary wet cell battery which is non-rechargeable and, therefore, disposable after depletion and the secondary wet cell battery, which is rechargeable.

Among the secondary wet cell batteries, there are three types: the starter lead-acid battery, the wet cell deep cycle battery, and the hybrid flooded battery. Here we will explain each of these.

  • Starter wet cell battery – This battery provides high bursts of power in a short period, and it is used to start cars, motorcycles, and other types of vehicles.
  • Deep cycle wet cell battery – Can be charged more frequently and to a higher depth of discharge (DoD) than the starter battery. The battery provides a stable voltage and small to medium currents for long periods.
  • Hybrid wet cell battery – Combines the best of both batteries in one robust design. The battery can be used as a starter and deep cycle battery at the same time, being perfect for RVs, boats, and similar vehicles.

Advantages and Disadvantages of Wet Cell Batteries

Wet cell batteries have several advantages when compared with other technologies. Flooded batteries tend to be much cheaper. They are a highly mature technology, tolerate charging with wider voltage ranges, and are perfect for backup power applications like off-grid homes and industrial backup systems. Lead-acid batteries are recyclable and end up producing less waste.

While there are many benefits, lead-acid flooded batteries have some disadvantages. These batteries have a lower life span and degrade during their lifetime. The user also has to perform wet cell battery maintenance regularly to avoid sulfating. Lead-acid batteries have a low energy density, which is why the wet cell phone battery ended up being replaced by lithium-ion cell phone batteries.

Long-Term Use and Replacement

Regularly using a lead-acid wet cell battery can degrade faster in the long term. This is caused by the expansion and contraction of the plates due to the charge and discharge cycle, which is why the plates corrode and end up reducing their overall size. Corroded plates are released in the form of flakes of sediment at the bottom of the cell. After some time, they end up short-circuiting the battery and killing it entirely.

Extremely hot climates can greatly reduce the life span of a flooded cell battery. This is caused either by the plate losing material or the water in the electrolyte evaporating. To avoid this, we recommend performing wet cell battery maintenance regularly, preventing water losses in the electrolyte.

Excessive vibration and overcharging could also reduce the life span of a wet cell battery. To prevent this, we recommend installing it at a fixed location and avoid moving it, providing maintenance on site.

Dry Cell Battery vs. Wet Cell Battery

One common discussion among battery enthusiasts and experts is defining the performance and differences of a dry cell battery vs. a wet cell battery. The main difference between them is the state of the electrolyte (dry or liquid), but both technologies can be used to manufacture primary or secondary batteries.

To ensure you have an educated opinion about the subject, we will provide the proper information about the dry cell battery vs. wet cell battery technologies.

Characteristics of the Dry Cell Battery

Dry cell batteries are manufactured using dry-state electrolytes. They use a metal electrode for the core, and the electrode is covered with an electrolyte paste. For lead-acid dry cell batteries, the paste is usually composed of manganese dioxide (MnO2) and ammonium chloride (NH4Cl), but this may vary.

Characteristics of the Wet Cell Battery

Wet cell batteries are manufactured using two insulated plates as electrodes (anode and cathode) and an electrolyte in liquid form. For the lead-acid wet cell batteries, the liquid electrolyte is made from sulfuric acid mixed with distilled water.

Advantages of the Dry Cell Battery

Dry cell batteries can be installed in any position and have longer life spans than wet cell batteries. They are safer and more portable, which is why they are used to power small devices. These batteries tend to lose power at a much slower rate and are, therefore, better for storing energy over long periods. Lithium-ion batteries, for instance, replaced wet cell phone batteries, since they have a higher energy density.

Advantages of the Wet Cell Battery

Wet cell batteries are regularly manufactured as secondary batteries for deep cycle and starter battery applications. Considering their life span and usages, flooded batteries are usually much cheaper compared to any other technology, especially when properly maintained. Wet cell batteries can withstand overcharging and charging with improper voltage, which is why they are more durable in that regard.

AGM vs. Wet Cell Batteries

While there are several dry-state cell batteries, one of the most important ones is the absorbed glass mat (AGM) technology. This is why we will compare the AGM vs. wet cell batteries and explain each one of them as well as the application they may be suited in.

AGM Batteries

AGM battery technology is one of the most important and commonly used sealed lead-acid (SLA) batteries. These batteries use fiberglass mats, creating a mesh within the battery that holds the lead-acid electrolyte by capillary action. This technology holds the liquid within its confined space, making it spill-proof, vibration-resistant, and even shock-resistant.

Due to the nature of their design, AGM batteries tend to have a lower internal resistance. This increases the output voltage and heat resistance of the battery, reduces the charging time, and provides them with more discharge cycles (longer life span).

The best quality AGM battery designs recombine the gases within the sealed case and turn them back to liquid, which is why they require very low maintenance and in some cases are entirely maintenance-free. AGM batteries offer an 80 percent max DoD, since these batteries have more cycles at a higher DOD, meaning they are more efficient.

Wet Cell Batteries

Up to this point, you might know the basics about wet cell batteries. They use a liquid electrolyte composed of sulfuric acid and water with insulated plates as the anode and cathode. These batteries tolerate a wider voltage range, provide high currents, and are much cheaper than AGM batteries. These are some of the reasons why lead-acid-flooded batteries are still active in the market.

Even though wet cell batteries are the cheapest option, they have some disadvantages. These batteries have a 50 percent DoD and a lower number of cycles than the AGM batteries, reducing their efficiency when compared with AGM technology. Wet cell batteries also have a low energy density and require regular maintenance.

One major advantage of wet cell batteries is that they can be recycled, producing less waste. You can even check out this video on how to make a wet cell battery, and learn how to make a wet cell battery from an old dead flooded battery that has surpassed its life span. We recommend you to only do this project if you already have experience working with these types of materials and wear proper protection.

Which Is Better: AGM or Wet Cell Batteries?

In the end, the AGM vs. wet cell battery battle is all about the price, applications, and preference. AGM batteries require much less maintenance, are safer to install, and are resistant to vibrations, but they are more sensitive to charging parameters. Flooded batteries, on the other hand, are cheaper and tolerate higher charging voltage ranges but require regular maintenance and have to be properly transported.

If you are looking for something practical and portable, AGM batteries might be better, but they are more expensive. When looking to save some money and if you don’t mind the maintenance, a flooded cell battery is the best option.


Now you know what a flooded battery is, how they work, what a wet cell battery is used for, what its advantages and disadvantages are, and how they compare to new battery technologies.

Flooded batteries are still widely used nowadays in the retail market. They provide a much cheaper option and can better tolerate abuse in overcharging and improper voltage, which is why they tend to be more suitable for off-grid homes and all types of backup energy system applications.

There are some drawbacks to flooded batteries like regular maintenance, but these batteries remain to be one of the cheapest options for backup energy systems, especially for small, off-grid applications. They can also be recycled, which is a major advantage when compared with other technologies.

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