What Is AGM Battery and How Long Does It Last?

What Is AGM Battery and How Long Does It Last?

AGM (Absorbent Glass Mat) batteries are a type of sealed lead-acid battery that offers several advantages over traditional flooded batteries. They are commonly used in various applications, from automotive to marine and renewable energy systems. In this blog, we will explore what AGM batteries are, how they work, their pros and cons, their lifespan, common applications, and a comparison with lithium and standard batteries.

What Is An AGM Battery?

An AGM battery is a type of valve-regulated lead-acid (VRLA) battery that uses a fiberglass mat soaked with electrolyte to absorb and hold the acid solution. Unlike flooded batteries, AGM batteries are completely sealed, which prevents acid leakage and makes them maintenance-free. The absorbed electrolyte allows for a higher electrical capacity and better performance.

How Do AGM Batteries Work?

AGM batteries work by utilizing a mat soaked with electrolyte, which serves as a separator between the lead plates inside the battery. This mat allows for a higher surface area contact between the plates, resulting in lower internal resistance and improved electrical performance. The mat also immobilizes the electrolyte, making the battery spill-proof and resistant to vibration.

When the battery is discharged, the chemical reaction between the lead plates and the electrolyte generates electricity. During the charging process, the electrical current reverses the reaction, restoring the battery's capacity. AGM batteries can be recharged using a suitable charger designed for AGM batteries.

Pros and Cons of AGM Batteries

AGM batteries offer several advantages over traditional flooded batteries:

Pros of AGM Batteries

Maintenance-Free: AGM batteries are sealed and do not require regular maintenance, such as checking electrolyte levels or adding water.

Deep Cycle Capabilities: AGM batteries are designed to withstand deep discharge cycles, making them ideal for applications that require frequent and deep discharges, such as marine and RV use.

Spill-Proof Design: The sealed construction of AGM batteries prevents acid leakage, making them safe to use in various orientations.

Vibration and Shock Resistance: AGM batteries are more resistant to vibrations and shocks, making them suitable for off-road vehicles and boats.

Fast Charging: AGM batteries can accept higher charging currents, allowing for faster recharging times.

Cons of AGM Batteries

Higher Cost: AGM batteries are generally more expensive than flooded batteries due to their advanced design and technology.

Sensitive to Overcharging: AGM batteries are sensitive to overcharging, which can lead to reduced lifespan or even damage to the battery.

Limited Lifespan: While AGM batteries have a longer lifespan compared to flooded batteries, they still have a limited number of charge-discharge cycles before their performance starts to decline.

How Long Does an AGM Battery Last?

The lifespan of an AGM battery depends on various factors, including usage, charging and discharging cycles, temperature conditions, and maintenance. On average, AGM batteries can last anywhere from 3 to 5 years or even longer with proper care.

To extend the lifespan of an AGM battery, it is essential to follow the manufacturer's guidelines for charging and discharging, avoid overcharging or deep discharging. Find the cool and dry place to store the battery when you're not using it. Regularly inspecting and cleaning the battery terminals can also help maintain optimal performance.

Common AGM Battery Applications

AGM batteries find applications in various industries and sectors. Some of the common uses include:

Automotive: AGM batteries are used in vehicles equipped with start-stop technology or where a reliable power source is required.

Marine: AGM batteries are popular in the marine industry due to their vibration resistance, spill-proof design, and deep cycling capabilities.

Recreational Vehicles (RVs): AGM batteries power the electrical systems in RVs, providing reliable energy storage for lighting, appliances, and other onboard equipment.

Solar Power Systems: AGM batteries are commonly used in off-grid solar power systems to store energy generated by solar panels.

Emergency Backup Power: AGM batteries provide backup power in case of power outages, ensuring a continuous power supply for critical equipment.

AGM Battery vs Lithium & AGM Battery vs Standard Battery

AGM batteries and lithium batteries offer different advantages and are suitable for various applications.

Here is a comparison between AGM batteries, lithium batteries, and standard flooded batteries:

AGM Battery vs Lithium Battery

Lithium batteries have a higher energy density, longer lifespan, and faster charging capability compared to AGM batteries. However, AGM batteries are generally more cost-effective and offer better deep cycling capabilities.

AGM Battery vs Standard Battery

AGM batteries have a spill-proof design, require no maintenance, and are more resistant to vibrations and shocks compared to standard flooded batteries. Standard batteries, on the other hand, are generally more affordable but require regular maintenance and may be prone to acid leakage.

Are AGM Batteries Worth It?

Whether AGM batteries are worth it depends on the specific requirements of your application. AGM batteries offer numerous advantages, such as maintenance-free operation, deep cycling capabilities, and spill-proof design. However, they are generally more expensive than standard flooded batteries. It is important to assess your needs, budget, and the specific benefits that AGM batteries provide before making a decision.

Is it possible to charge an AGM battery using a regular charger?

Charging an AGM battery with a regular charger is not recommended. AGM batteries have different charging requirements compared to conventional flooded lead-acid batteries. Using a regular charger designed for flooded batteries may not provide the optimal charging status for an AGM battery. Therefore, it is essential to use a specific charger designed for AGM batteries when charging a 12V AGM marine battery. This ensures that the battery is charged correctly and maintains its performance and lifespan.

How do I know my battery is AGM? 3 Steps

Determining if a battery is AGM can be done by following these three steps:

Check the Label: Look for labels or markings on the battery that indicate it is an AGM battery. Manufacturers usually specify the battery type on the label.

Consult the Owner's Manual: Refer to the owner's manual of the battery or the equipment it is used in. The manual should mention the battery type and specifications.

Contact the Manufacturer: If the above steps are inconclusive, you can contact the battery manufacturer directly and provide them with the necessary details. They should be able to confirm the battery type based on the information you provide.


AGM batteries are a reliable and versatile option for various applications, providing advantages such as maintenance-free operation, deep cycling capabilities, and spill-proof design. They offer an alternative to traditional flooded batteries and have specific benefits that make them well-suited for automotive, marine, RV, and renewable energy systems. By understanding how AGM batteries work, their pros and cons, lifespan, and common applications, you can make an informed decision when choosing the right battery for your specific needs.

Looking for a battery replacement in Calgary? Shop AGM batteries from Batteries Store Calgary.

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