what is an agm battery

What Is an AGM Battery: The Pros and Cons

In the world of energy storage and power solutions, battery technology has evolved rapidly. Among the innovative new battery types, AGM batteries stand out for their enhanced performance and versatility. With their advanced design and unique characteristics, AGM batteries have carved a niche for themselves, offering a compelling alternative to traditional battery types.

AGM batteries are known for their high performance in demanding applications, such as start-stop vehicles and RVs. They are also well-suited for deep-cycle applications, such as solar and wind power systems.

In this article, we will discuss the basics of AGM batteries, including their construction, advantages, and disadvantages.

What Is An AGM Battery?

AGM batteries are a cutting-edge evolution in battery technology that has revolutionized energy storage and power distribution. These sophisticated sealed lead-acid batteries are designed to address the limitations of traditional flooded lead-acid batteries, offering improved performance, enhanced safety, and a wide range of versatile applications.

So what does AGM battery mean? An AGM battery, or Absorbent Glass Mat battery, is a type of lead-acid battery that uses an absorbent glass mat to separate the electrolyte from the plates. This makes them different from traditional lead-acid batteries, which have a liquid electrolyte.

The glass mat is made of fiberglass that is saturated with electrolyte. The electrolyte is a mixture of sulfuric acid and water. The plates are made of lead and are arranged in a stack. The glass mat absorbs the electrolyte and prevents it from leaking out of the battery. This makes the battery maintenance-free and spill-proof, and it also improves its performance in demanding applications.

AGM batteries are commonly used in start-stop vehicles, RVs, and solar power systems. They are also a good choice for deep-cycle applications, such as trolling motors and golf carts.

For a 12-volt AGM battery, the absorption voltage typically ranges from 14.2 to 14.4 volts, while the floating voltage is lower, typically around 13.2 to 13.6 volts.

what is an agm battery
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Advantages Of AGM Batteries

Basically, the operating principle of AGM batteries is the same as other lead batteries. However, when compared to flooded batteries, AGM batteries for RV have been shown to have some significant improvements to make them more efficient:

Spill and leakproof

Spill-proof construction is due to the fact that the electrolyte is held within the mat rather than sloshing around in liquid form. A focal feature of this battery line is the sealed battery technology. Prevent air and liquid from outside from entering and vice versa. Therefore, it can be placed in many directions or moved without worrying about leakage problems like conventional water or MF batteries.

In addition, equipping a VRLA (Valve Regulated Lead Acid) pressure regulator is considered a bright plus when it is possible to adjust the high pressure inside the tank to standard pressure to ensure safe operation.

Provide high power and low internal resistance

Due to AGM’s design, an AGM battery for RV has minimal internal resistance. This, therefore, enables them to provide sufficient power when necessary, such as when drivers start their batteries. Thanks to this feature, these batteries respond better to loading than any other battery on the market.

An AGM battery was proven to deliver more electrical power than EFBs can and recharge up to 5 times faster. AGM batteries meet all requirements for a stable power supply. Fiberglass spacers increase Start-Stop usage by up to 4 times. VRLA-sealed construction increases charging capacity by over 150%. Theoretically, AGM batteries actually dissipate slower than conventional batteries and again they can bounce back from the discharger easier than even a deep cycle.

Special plastic shell material: Optimizing safety, especially in vehicles with batteries in the passenger compartment and seats.

Improved vibration resistance

Vibration resistance due to its sandwich-like construction. Thanks to this special structure that allows AGM to hold up a lot of force and can stand up to weather-related wear and tear. AGM batteries are built up to withstand great vibration, all of that making this type of battery becomes the right choice for heavy machinery. 

Higher cycle life than flooded batteries

AGM batteries are capable of operating for a longer period of time than conventional flooded batteries. This is because these batteries minimize self-discharge, unlike other batteries, which is a big problem. This ensures that one does not have to keep charging them after a long period of inactivity. 

Disadvantages Of AGM Batteries

Just like other lead batteries, in addition to many advantages, AGM also has   certain disadvantages:

  • The deep cycle AGM batteries can only be discharged to 50% whereas the lead acid battery can be discharged to 80%. This means that the lead acid battery can run appliances longer on every single charge. Drivers should be careful when charging these batteries as charging too much and too little can affect their lifespan and performance.
  • Another downside of this battery is its price, you will need to pay from $200 to $300 to have an AGM battery. This price is said to be twice as expensive as conventional lead-acid batteries. The price of this type of battery is more expensive than other types because of the high production cost. However, in return, the life of AGM batteries is often much longer than that of lead-acid batteries. Engineered AGM batteries are built to provide up to twice the life of a standard flooded battery. At that time, their disadvantage will become an advantage as you consider the lifespan of this battery.
  • Although the output power is quite high, the specific energy of the AGM battery is a bit low. If your car is using AGM batteries for a long time, we’re sure you also know that AGM batteries can only be used under moderate loads to reach high specific loads. As a result, your vehicle may not be able to power some devices that use AGM batteries.

AGM Battery vs Gel Battery: What Are The Differences? 

Many drivers reckon mistakenly that  AGM batteries and Gel batteries are the same. Although both types of batteries possess similar characteristics such as spill-proof construction and can be used in different orientations. However, these two types of batteries are completely different.

  • As we know, AGM batteries use a special glass mat made up of thin glass fibers to absorb the electrolyte between the battery panels. On the other hand, Gel batteries use silica gel to hold electrolytes together. Electrons can freely move between the plates thanks to the thick consistency of the material.
  • Gel batteries can lose energy faster than AGM batteries at lower temperatures due to the battery’s Thixotropic gel composition. Because AGMs can operate in extreme weather conditions, they are better able to maintain power.
  • In contrast, Gel batteries can use acid better than AGM batteries when talking about the depth of discharge (DoD). Acids help protect the ranges of the gels which enhances their deep flushing applications.
  • Compared to Gel batteries, the price of AGM batteries can be cheaper comparably. However, this type of battery has a longer life than a Gel battery and provides bigger bursts of the amp when your vehicle needs it.  
  • If kept in a charged state when unused, the common 12-volt AGM or Gel batteries can last up to 6 years. After 5 or 6 years of float voltage at an average ambient temperature of 25°C. These batteries still retain 80% of their original capacity. 

There are also several observations to identify an AGM battery.

How Long Does an AGM Battery Last?

The lifespan of an AGM (Absorbent Glass Mat) battery can vary depending on various factors such as its quality, usage patterns, maintenance, and environmental conditions. On average, a well-maintained AGM battery can last anywhere from 7 to 10 years, but some high-quality models can last even longer.

AGM batteries last longer than other SLA battery types due to their unique design features. The fiberglass mat separator in AGM batteries reduces acid stratification, ensuring more stable performance over time. They also have a lower self-discharge rate, allowing them to hold their charge better during periods of inactivity. AGM batteries are more resistant to vibrations and shocks, making them ideal for automotive use. Additionally, they accept higher charging currents, charge faster, and handle deep cycling more effectively. Their improved sealing prevents leaks and electrolyte evaporation, enhancing safety and durability. Being maintenance-free, AGM batteries are a reliable and long-lasting power storage solution for various applications.

It’s essential to note that AGM batteries are commonly used in vehicles, boats, RVs, and other applications where reliable power storage is needed. To extend the life of an AGM battery, consider the following tips:

  • Proper charging: Ensure the battery is adequately charged, as both overcharging and undercharging can affect its lifespan.
  • Temperature: Extreme temperatures can impact battery performance and life. Avoid exposing the battery to excessively high or low temperatures.
  • Avoid deep discharges: Frequent deep discharges can be detrimental to AGM batteries. Try to avoid fully discharging the battery whenever possible.
  • Regular maintenance: Keep the battery clean, check for signs of corrosion, and ensure the terminals are secure.
  • Reputable brands: Choosing a reputable brand for your AGM battery can also contribute to its longevity.
  • Usage: The battery’s lifespan will also be affected by how often it is used and the intensity of its usage.

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