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The knowledge about batteries is essential to ensure the vehicle performance and battery maintenance. Take AGM batteries, for example, which can deliver on-demand high currents and are almost maintenance-free despite having a long lifespan. An AGM battery is different from a Gel-filled or liquid lead-acid battery.

How do I know if my battery is AGM? Well, you need to learn about that to make sure the right kind of battery maintenance. But first of all, take a look at the importance and working process of the battery.

What Is an AGM Battery?

A battery is a component that works as the power supplier of the vehicle’s electrical parts. Whether it is starting the car, blowing the horn, securing car locks, wiping the windshield, illuminating lights, or playing music, nothing will work without the battery.

In the latest additions to the car market, namely the Electric Vehicles (EVs), the battery is the prime source of power that runs the car. Generally, car batteries are rechargeable.

If you’re camping on the wild or go on road trips for a long time, the battery is even becoming more indispensable to supply power for RV appliances like: AC, TV, lights,… which can ensure your comfort during the trip.

Before delving into the details about AGM batteries, let’s find out about the mechanism of a regular battery.

Working Process of a Vehicle Battery

After turning on the ignition key, the electrical energy stored within the battery powers the engine starter, cranking up the engine. The battery energizes other electrical components at the same time. As the cars come with rechargeable batteries, the alternator recharges the battery while it’s in use.

Occasionally, a vehicle parked in a garage for long will badly impact the battery charge level. To have a sufficient battery charge, use the vehicle frequently, or it will require a jumpstart.

How do I know if my battery is AGM? The next section will give you a basic idea about this battery type.

AGM Battery: Definition and Composition

There are various types of batteries, and AGM is a popular kind. AGM stands for Absorbent Glass Mat, and this variant became widespread in the early 1980s.

This battery uses a fiberglass mat to soak up the principal component, which is sulfuric acid. It makes the battery leak proof and highly mobile. The fiberglass mats can be of any shape – flat mats for quadrilateral batteries or round mats for cylindrical cells. Absorbent fiberglass mats separate the positive and negative plates in the AGM technology batteries.

An opened agm battery
An open AGM battery. (Source: Bullenwächter / Wikimedia Commons)

Inside each cell, the plates remain under pressure and in a highly compressed environment. This environment confirms the limited shedding of the negative/ positive electrodes, offering longer life to the AGM battery. Such packing of plate materials and fiver-glass mats within the AGM batteries ensure superior pulse power output and reduced internal resistance.

The batteries have a rigid container to facilitate the above features. A battery box also comes with a valve to emit any minor gasses within the battery. This valve does not allow the air to leak into it due to its unique design. AGM batteries come at a range of 30 to 100Ah. To save the battery from heat, manufacturers place it away from the engine block.

How Do I Know If My Battery Is AGM?

An AGM demands separate handling procedures than other battery types. Therefore, you must know which battery is installed in the car for its proper maintenance. An AGM unit is comparatively durable, portable, and secured than traditional wet cell batteries.

There are three widely used methods for finding the battery type:

Method 1

This method is about closely inspecting the printed labels of the batteries. If it is an AGM battery, any of the following words will be there.

  • AGM
  • Absorbed Glass Mat
  • Dry Cell
  • Sealed Regulated Valve
  • Non-Spill
  • Regulated Valve

On the other hand, flood lead-acid or liquid batteries will have a label, containing terms like “lead-acid,” “flooded lead-acid,” “liquid lead-acid,” “Gel-filled,” or “wet cell.”

Method 2

This method involves looking into the battery structure. If the battery is liquid lead-acid type, it will have removable tops or caps. But AGM units come with a flat top that also contains positive and negative endpoints.

Shaking is another option to confirm the type. Shake the battery to see if it jiggles. If yes, then the battery is a liquid lead-acid variant. Otherwise, it is an AGM type.

Warning: Shaking the battery requires adhering to safety protocols, such as wearing rubber gloves and eye protection gear like goggles.

Method 3

How do I know if my battery is AGM? If the first two methods don’t yield anything, this third step will help. You need to take the help of the battery manufacturer’s website.

Even if the battery label is missing, you can identify the type. There will be a unique serial number printed on the battery. Through this serial number, manufacturers track battery-related services like warranty and maintenance. Access the respective manufacturer’s website and use that number to find out the battery type.

Advantages of Using an AGM Battery

Because of the following benefits of the AGM battery, it is more popular than other types.

  • AGM batteries can deliver high currents on demand due to the low internal resistance. As a result, it has a relatively long service life, even if it goes through the process of deep cycling.
  • Compared to the liquid lead-acid type batteries, AGM is lighter and offers better electrical reliability. It is also maintenance-free because of not allowing the lead sulfate crystals to build up quickly. It also does not require a charge in short intervals, even when unused, due to a low self-discharge rate.
  • The prime benefit of AGM batteries is their charging ability. It can charge up to five times faster than the batteries with flooded technology.
  • At the same time, it can deep cycle. AGM has a depth-of-discharge rate of 80 percent, while the liquid batteries need a 50 percent depth-of-discharge to reach the same cycle life.
  • During any car accident, AGM batteries will not spill any acid. Being lighter than liquid lead-acid units, AGM batteries allow installation at critical angles. Performance is also reliable at cold temperatures. Therefore, marine, motorhome, and robotic appliances prefer the AGM type.


How do I know if my battery is AGM? You can find that out easily by following the methods mentioned above. Among different variants of batteries, AGM enjoys higher popularity because of its impeccable features.

About Peter Wade

Peter Wade is a co-ordinator and writer at His hobbies are coffee, RV camping and photography. He now enjoys exploring the U.S. by RV with his two dogs. After obtaining a MA degree in Public Relations and Journalism, he had 8 years of experience working for the R&D Department of Outdoorsy. Peter provides a unique look and insightful knowledge about the RV lifestyle, and fills his blog with everything from RV camping guides to reviews about necessary RV accessories. If you are an RV enthusiast and want to get the most-updated trends of the RV industry, Peter’s articles are the must-visit contents.

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