What Is An AGM Battery: Best For Solar System

What Is An AGM Battery

Have you been asked what an AGM battery is before, or are you confusing it with other batteries? Then this article on what an AGM battery is will do justice to that.

You’re in the right place. In this Powerversity guide, you’ll find out all you need to know about AGM batteries.

However, I’ll explain this article in sections for better understanding.

In the first section, I’ll give you an overview of AGM batteries.

If we’re being honest, there are people who don’t even know how an AGM battery works or what it’s used for.

That notwithstanding, in the next section, I’ll explain to you how this type of battery works.

Moving further, I will highlight some of the pros and cons of AGM batteries.

This will help in choosing the right one that meets your needs.

The next sections contain the features and factors to consider and my recommendation in a comparison table.

In the last section, you’ll find my final thoughts. There, I summarized all that has to do with AGM batteries.

So, if you want to get the most from this article, I’ll advise you to read to the end, and it will help you in no small way.

Without wasting much time, let’s quickly dive into it.

Overview – What Is An AGM Battery

An absorbent glass mat (AGM) battery is an advanced type of lead-acid battery that uses an absorbent fiberglass mat as a separator between the lead plates.

The separator helps keep the acid from spilling out while allowing current to flow through the battery.

AGM batteries have highly effective internal make-up that provides superior power to support the high electrical demands of today’s sophisticated vehicles.

They are normally sealed, non-spillable, maintenance-free, and rechargeable.

Also, these types of batteries are commonly used in UPS systems, emergency lighting, alarm systems, and other applications where a sealed, maintenance-free battery is desired.

Due to their well-optimized cell design and compression, they can easily handle vibration in most high-electrical demand vehicles.

More importantly, their minimal gassing and acid leakage offer better overall performance than conventional lead-acid batteries.

So, I recommend you invest in it; believe me, you’ll be happy you did.

How Does AGM Battery Work

An absorbent glass mat battery is a lead-acid battery that uses a fiberglass mat as a separator between the lead plates.

The mat usually absorbs the electrolyte, thereby allowing the plates to be suspended in the electrolyte.

This increases the surface area of the plates and also improves the battery’s performance.

Also, absorbent glass mat batteries are more efficient and require less maintenance than conventional lead-acid batteries.

When charging, the positive and negative plates of the battery are often flooded with an electrolyte solution.

On the other hand, the fiberglass mat absorbs the electrolyte solution, which then acts as a separator between the plates.

As a matter of fact, the electrolyte solution is, in this process, retained in the mat and cannot escape, thus preventing the battery from leaking.

During discharge, the lead plates are oxidized, and the electrolyte solution is released from the mat and carries the electrical charge to the battery terminals.

Interestingly, this process is reversed, especially when the battery is recharged.

Also, and for obvious reasons, AGM batteries generally have a longer life cycle than conventional lead-acid batteries.

They are also more efficient at storing and delivering energy, making them ideal for high-power vehicles.

Pros And Cons – What Is An AGM Battery


High Power Output

Due to their internal design, AGM batteries turn out to also have low internal resistance.

For this reason, they are able to offer high power output in short bursts, which, of course, is perfect for use in all vehicles.

This makes them the preferred choice for vehicle owners, especially those who have high-electric-demand vehicles.


Another advantage of AGM batteries is that they are completely spill-proof.

The fiberglass mats inside the AGM battery help prevent spillage, as they can hold electrolytes without letting them flow freely.

In fact, the electrolyte solution is usually retained in the mat and cannot escape, thus preventing the battery from leaking.

So even though you place the battery in different positions, you can rest assured that there won’t be any leakages.

Short Charging Time

When it comes to the rate at which they charge, AGM batteries often outshine regular batteries in this regard.

They can be fully charged in a short period of time, unlike the flooded lead-acid battery, which takes almost forever to charge to full.

If you take your time to measure the rate at which a regular battery charges and compare it to that of an AGM battery, you’ll definitely notice that the latter is 5 times faster.


AGM batteries are generally very durable and sturdy due to their internal design.

Initially, they were designed to serve the aircraft industry, as they could handle the intense vibrations from aircraft engines.

However, with time, they became a favorite for high-end motorcycle riders and race car drivers.

The way the AMG batteries are constructed helps prevent their internal components from falling apart.

As such, they can handle the vibrations produced by the engine of your vehicle without encountering any problems in the long run.

Longer Lifespan

AGM batteries generally have a longer life cycle than conventional lead-acid batteries.

In fact, you can use them for much longer periods than regular lead-acid batteries.

On average, an AGM battery can last for up to seven years. After that, however, it depends on the manufacturer of the battery.

There are some that can last for ten years and even more.

Unlike regular batteries, AGM batteries have a low self-discharge rate. This is especially good if you don’t drive your vehicle all the time.

Less Sulfation Build-Up

To begin with, in regular lead-acid batteries, lead sulfate crystals always accumulate in the battery cells, causing a battery failure.

Therefore, in order to prevent such from happening, you’re often required to charge your regular lead-acid battery every six months. I really don’t fancy that idea.

Well, the AGM battery is totally different. You really don’t need to charge them every so often because sulfating is less common.


High Manufacturing Costs

AGM batteries are known to have a high manufacturing cost, which ultimately affects the price of the battery.

This is due to the effective internal design of the battery.

However, they’re still cheaper to produce than other battery types, like gel-type batteries.

Though their cost of production may have reduced since their introduction into the market, they’re still very expensive compared to other batteries.

This makes them expensive, especially for those who may not have the necessary means of affording them.

Energy Issue

Although they have a higher power output than regular batteries, their specific energy is a bit low.

If you’re using an AGM battery for whatever purpose, it’s important to know that you can only use them under a moderate load to achieve a high specific load.

In other words, you may be unable to power some devices using an AGM battery.

Sensitive To Overcharging

One thing about an AGM battery is that it is very sensitive to overcharging.

If, out of ignorance, or maybe accidentally, you overcharge your AGM battery or charge it at a high voltage, it can shorten its lifespan.

Therefore, you must charge it at the appropriate level or recommended voltage.

This will help to improve the battery’s performance.

Reduced Capacity Overtime

The fact that AGM batteries can hold a charge for a long period of time makes them really impressive.

However, there’s a downside to this. It can reduce their charging capacity after a long period.

Important Factors To Note When Buying An AGM Battery

Here are some of the factors you should consider before buying an AGM battery.

Battery Freshness

A code usually marks the battery’s freshness, consisting of both a letter and a number.

The letter on the battery stands for the month, whereas the number stands for the year it was manufactured.

To some extent, the battery’s freshness will determine how long it will last.

So, it’s important that you take note of this.

Don’t spend your money on a battery that is older than six months from the date of manufacture.

Reserve Capacity

Aside from the battery’s freshness, another important thing you should look out for is the performance of the brand or model.

There are no doubt different brands and models on the market right now, with some offering better performance than others.

However, the battery performance varies from year to year.

So, look for the top-performing batteries for the year.

Thereafter, you should look out for brands and models with good ratings.

This will help you make the right choice.

A battery with a good reserve capacity will serve you best.

The reserve capacity has to do with the amount of time it can run on its own without the power of the car.

Therefore, having a high reserve capacity battery will help ensure that your car doesn’t go dead even if you forget to turn the lights off.


Just like I’ve said before, there are different types of batteries. Some are low-maintenance, whereas some are maintenance-free, like AGM batteries.

Maintenance-free batteries are usually sealed, and you don’t need to replace the liquid electrolyte in the battery at any point during use.

However, low-maintenance batteries, on the other hand, have unsealed caps and require you to occasionally add distilled water to them.

Without regular maintenance, they could stop working. So, those who use them need to service them every six months.

Nevertheless, if you want to avoid the stress of owning a flooded lead-acid battery, go for an AGM battery.


Another factor you should consider when buying an AGM battery is the manufacturer’s warranty.

I can assure you that this is where most buyers get it totally wrong.

More often than not, they buy a product without looking for the manufacturer’s warranty.

Don’t be like one of those people.

Instead, always ensure that you choose a battery that has a longer warranty and allows you to replace it for free.

Ampere Hour (Ah)

Basically, this has to do with the amount of energy that the battery can store within a period of time, usually on an hourly basis.

A higher Ah means that the battery can carry a load for a long time.

Thus, the chances of it running out are less.

Therefore, before you buy any AGM battery, check properly to know if it has a high Ah.

You can as well ask the dealer, just in case you’re a bit confused.

And as the saying goes, this will help you avoid spending a lot on the wrong things.

Battery Life

AGM batteries, as I’ve said before, are maintenance-free.

In other words, they don’t require occasional servicing like the flooded lead-acid batteries.

However, there are certain practices that may undermine the battery’s lifespan.

For instance, overcharging it or charging it at a high voltage can affect its performance.

Meanwhile, you can check your battery’s life at an auto parts store or battery specialist.

This will help you to know the current state of your battery and if it needs replacement.

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My Recommendation And Specifications Table

Product NameDimensionsWeight Battery CompositionVoltageBrand
ML100-12 – 12 Volt 100 AH, Internal Thread (INT) Terminal, Rechargeable SLA AGM Battery12.17 x 6.61 x 8.31 inches59.9 poundsSealed Lead Acid12 VoltsMighty Max Battery
WEIZE 12V 100Ah Deep Cycle AGM Battery, Rechargeable SLA Battery12.99 x 6.73 x 8.34 inches63.4 PoundsLead-Acid12 VoltsWEIZE
XS Power XP950 XP Series 12V 950 Amp AGM Supplemental Battery with M6 Terminal Bolt10 x 12 x 13 inches25.15 PoundsLead-Acid, AGM12 VoltsXS Power
Renogy Deep Cycle AGM Battery 12 Volt 100Ah, 3% Self-Discharge Rate, 2000A Max Discharge Current13 x 6.8 x 9 inches66 PoundsLead-Acid, AGM12 VoltsRenogy
ACDelco Gold Automotive AGM Battery 94RAGM With 36 Month Warranty, AGM BCI Group12.4 x 6.9 x 7.5 inches51.6 PoundsSilver-Calcium12 VoltsACDelco
Click here to buy any of the above-listed AGM Batteries

Frequently Asked Questions – What Is An AGM Battery

1. What Is An AGM Battery?

An absorbent glass mat battery as a lead-acid battery uses a fiberglass mat as a separator between the lead plates.

2. What is the advantage of an AGM battery?

An AGM battery is usually lighter and maintenance-free compared to a regular battery. It also has a higher resistance to chemical corrosion.

3. What’s The Difference Between AGM And A Regular Battery?

AGM batteries are highly resistant to chemical corrosion. As such, they last longer than conventional or regular lead-acid batteries.

4. How Often Should An AGM Battery Be Charged?

To keep the battery in good working condition, ensure that it’s fully charged at least every three (3) months.

5. How Do I Know If My Battery Is AGM?

To know if your battery is AGM, check if it’s sealed. AGM batteries are usually sealed, with only the negative and positive terminals of the battery sticking out.

6. Can I Charge An AGM Battery With A Regular Charger?

No, you cannot. The reason is that they have different charging requirements.

7. What Is The Main Disadvantage Of An AGM Battery?

It is very expensive to produce. The high manufacturing cost sometimes makes the battery also to be expensive.

8. How Long Does It Take To Charge An AGM Battery?

Most AGM batteries have 100 amp-hours. As such, with a 10 amp charger, it would take between three and nine hours to fully charge your battery.

9. How Long Will AGM Battery Last?

On average, an AGM battery can last for up to seven years.

10. Do AGM Batteries Charge Faster?

The simple answer is, yes, they do. In fact, you can charge them up to five times faster than regular batteries.

My Final Thoughts – What Is An AGM Battery

What Is An AGM Battery: My Final Thoughts
Image Credit: pexels.com

Consider getting one of these, and I assure you it’ll be worth every penny.

As I said earlier, this type of lead-acid battery uses an absorbent fiberglass mat as a separator between the lead plates.

The separator helps keep the acid from spilling out while allowing current to flow through the battery.

Generally, AGM batteries are well-sealed, maintenance-free, and rechargeable.

They are commonly used in UPS systems, emergency lighting, and other applications where a sealed, maintenance-free battery is desired.

Due to their well-optimized cell design and compression, they provide superior power and vibration resistance in most high-electrical demand vehicles.

What’s more, even for a top-tier lead-acid battery, AGM batteries are generally very affordable.

So basically, you don’t have any excuse for not getting one of these.

Meanwhile, if you’re not sure which one to go for, you may as well use my recommendation on the best 5 AGM batteries.

Just click on any of the products, and look for the one that suits your budget and meets your needs.

I hope you found this article helpful. You can also share your thoughts with us by using the reply form below.

Also, for more reviews, please visit the following pages:

How To Charge A Deep-Cycle Battery

What Is A Solar Battery

5 Best Power Banks

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Akin-Ojo Victor
Victor Akin-Ojo is the founder and the Lead Editor of PowerVersity.com. Before starting PowerVersity.com, Victor worked in the IT industry for nearly 15 years as Field Support Engineer for VSAT, Networking, and Wimax Technologies. He also work in the power sector for close to 10 years. He currently run a blog - powerversity.com, where he share his knowledge on Alternative Energy Solutions.