If you’re unsure whether your battery is an AGM battery, I will go through how to find out below.
They resemble ordinary “flooded” or “wet cell” lead-acid batteries. That’s because they are essentially the same and share many features in common. But they are built differently and usually for a more specific purpose.
Ways to know if your battery is an AGM battery:
- It is typically spill-proof due to being sealed and maintenance-free, allowing for flexible mounting.
- It doesn’t require ventilation and offers vibration resistance, distinguishing it from a regular flooded battery.
- It is specially designed to provide startup power and versatility, and many, though not all, deep-cycle batteries are AGM. It makes them especially suitable for high-cranking power in cars, motorcycles, small electric vehicles, solar-powered systems, and marine use.
- It can be recognized from brand series like Duralast Platinum and Napa Legend Premium.
- It can be expected to last at least three and up to 5-8 years.
- Has a glass mat separator internally.
AGM Batteries
An AGM (Absorbed Glass Mat) battery comprises a special glass mat separator, which wicks the electrolyte solution between the plates.
The fiberglass between its plates saturates the electrolyte and stores it in a suspended dry state instead of liquid form. While working, the electrolyte transfers from the mat to the plates.
This design makes it more flexible than a standard wet-cell battery. Although not as spill-proof as gel-type batteries, they can still be mounted more flexibly and don’t require maintenance either.
A Small Sample
Here’s a small sample of popular AGM batteries used for cars that you might recognize.
If your battery looks like one of those shown below (not an exhaustive list), it’s probably an AGM battery.
It’s usually easy to tell if the label is intact and mentions “AGM,” but if not, I’ll tell you more about AGM batteries and how they differ from other battery types, i.e., more ways to tell them apart.
More Ways to Tell AGM Batteries Apart
Appearance
You will have noticed that AGM batteries look much like ordinary lead-acid batteries.
They are roughly the same shape and size. For example, you might not be able to tell the difference between these three batteries under the brand name of Duralast from a distance or if the labels are missing or torn.
All three Duralast batteries look very much similar. But if you know how the different types are named, you’ll know that the Duralast Platinum one is the AGM battery (the one on the right).
Similarly, the Napa range of three batteries also includes an AGM type, but they look similar.
Check the Brand
Check the battery’s brand.
It could be an AGM battery if made by one of the brands listed below. It’s just a small sample of two brands, as there are many others also associated with AGM batteries:
- Duralast Platinum – These batteries are ideal for power, durability, and flexibility compared to ordinary lead-acid batteries. They have robust construction and a spill-proof design and are especially suitable for versatile uses.
- The NAPA Legend Premium battery is for those who prefer a hassle-free experience and need high-cranking power.
Check the Manufacturer
Check the manufacturer to see if they make AGM batteries.
For example, the following manufacturers make AGM batteries (not exclusively):
- Clarios took over from Johnson Controls and is one of the world’s largest battery manufacturers.
- In Berks County, Pennsylvania, East Penn Manufacturing is also one of the world’s largest battery manufacturers. It makes AGM batteries under Duralast, Napa, West Marine, etc.
- Exide makes the Duralast brand an OE supplier.
Lifespan
One distinguishing feature of an AGM battery is its typical lifespan.
Normally, an AGM battery can last from 3 to 5 years before it has to be replaced, but it can last longer, up to 8 years, if well-maintained. So it offers a longer lifetime than traditional (flooded) lead-acid batteries.
A gel battery (a less often used alternative) offers a 3-6 year lifespan, which is comparable, and a lithium battery can last longer than five years as well by allowing more charge-discharge cycles. Both types, however, are much more expensive.
Cross-Comparison
I’ve created a chart to help you distinguish between AGM and other common battery types.
Like AGM batteries, traditional lead-acid batteries (also called flooded or wet cell batteries) and gel batteries are filled with acid as the electrolyte. But AGM and gel batteries are more maintenance-free because they are sealed, whereas lead-acid batteries require frequent topping up with water.
The AGM Advantage
As the comparisons show, AGM batteries are preferred because they offer advantages over lead-acid and other types of batteries.
In particular, AGM batteries:
- Cost – They are costlier than lead-acid batteries but cheaper than gel and lithium batteries.
- Flexible mounting options – They have a lower risk of spillage than lead-acid, although not as much as gel batteries.
- Lifespan – They usually last longer than lead-acid batteries (3-5 years, compared to 2-4 years), about as long as gel batteries, but less than lithium ones.
- Power – AGM batteries provide powerful bursts of starting amps.
- Reliability – They are generally more reliable than lead-acid and gel batteries but less so than lithium batteries.
- Safety – They are generally safer than lead-acid but not as much as gel batteries.
- Versatility – They are more suitable than lead-acid batteries for versatile uses, such as powering infotainment systems and heated seats.
Are You Still Unsure?
If you’re still unsure whether your battery is an AGM one, here’s a quick rundown of questions you can ask yourself based on all the information in this article. I hope it helps.
For example:
- If the battery looks like a regular lead-acid battery but is sealed and doesn’t require checking its water level, it’s probably an AGM battery, but it might be a gel or VRLA battery. It won’t be lithium.
- You can rule out the lithium type if it’s a lead-acid battery. It might be flooded/wet-cell lead-acid, AGM, VRLA, or gel type. But if there’s a gel inside instead of liquid, you can rule out the gel battery.
AGM Batteries in Other Vehicles and Use Cases
AGM batteries are also used in other (than car) vehicles, including motorcycles and RVs, and for off-grid, solar, and marine applications.
AGM Batteries for Motorcycles
Those used in motorcycles might look like one of those shown below.
AGM batteries are more popular than wet cell batteries for motorcycles because they can be mounted flexibly due to a lower risk of spilling. They are also considered to be relatively safer.
AGM Batteries for Small Electric Vehicles
Flexible mounting and lower risk of spillage are also important factors for small electric vehicles, hence the preference for AGM batteries like the ones below.
The VRLA AGM battery shown above is specially designed for vehicles such as golf carts and provides 200 Ah. It is described as “useable in any position” and has a low self-discharge rate, which makes it ideal for this use case.
Duracell’s “Platinum AGM” is a deep-cycle battery specially designed for golf carts. It operates at 6V and is “ideal for deep cycle applications.”
AGM Batteries for Solar-Powered Systems and Marine Use
You may have noticed that the AGM batteries used are typically “deep cycle” for off-grid, solar-powered, and marine applications.
That’s because they are specially designed to be deeply discharged regularly, thereby using most of their capacity. They typically have thick plates.
However, not all deep cycle batteries are AGM. Some are, but some deep cycle batteries are also made in gel type.
Here are a couple of batteries used to provide backup power in solar-powered systems:
For example, the Siga AGM battery is specially made for solar-powered applications. It’s a 100Ah battery that is airproof-sealed, has fire and spark protection, and comes with extra thick plates to facilitate deep discharging.
The Solarfam AGM battery provides 150Ah and is specially designed for camping and caravans, i.e., “small isolated installations.”
Taking Care of Your AGM Battery
Although AGM batteries are generally more reliable than ordinary lead-acid and gel batteries, you still need to take good care of them to make them last as long as possible.
If you manage this, you could make your AGM battery last up to 8 years, which may even outlast a lithium battery. To help you achieve this potential longevity, the main thing to be aware of is the charging and discharging pattern.
Over- and undercharging can both affect the performance and lifespan of AGM batteries. It could shorten their lifecycle significantly. Limit the discharge to no more than 50-70% for best performance and longevity.
References
Amp Tech AGM battery: https://5starscooters.com.au/products/mk-70-amp-gel-battery
An AGM battery: https://www.ebay.com/itm/Vertex-Battery-For-Suzuki-DL-650-AUE-V-Strom-ABS-2015/392508423231
Duracell Platinum AGM battery: https://www.samsclub.com/p/duracell-agm-golf-car-battery-group-size-gc2agm/prod3870119
Duralast Gold battery: https://www.autozone.com/batteries-starting-and-charging/battery/p/duralast-gold-battery-27-dlg-group-size-27-810-cca/115785_0_0
Duralast Platinum: https://www.autozone.com/batteries-starting-and-charging/battery/p/duralast-platinum-agm-battery-h6-agm-group-size-48-760-cca/319460_0_0
Everstart Platinum AGM battery: https://www.walmart.com/ip/EverStart-Platinum-AGM-Battery-Group-H6-12Volt-760CCA/944775111
Exide AGM battery: https://www.osculati.com/en/11377-12.412.02/exide-agm-battery-100-ah
Interstate AGM battery: https://www.interstatebatteries.com/products/31m-agm
Motolite Excel AGM battery: https://www.motolite.com/products/motolite-excel-agm
Napa legend battery: https://www.napaonline.com/en/p/BAT7558
Napa Legend premium battery: https://www.napaonline.com/en/p/BAT9849
Napa power battery: https://rapsonline.com/promotions/save-on-napa-batteries/
Power AGM battery: https://www.tools.com/power-agm-135ah-sla-12v-deep-cycle-battery
Renogy deep cycle AGM battery: https://www.lowes.com/pd/Renogy-Renogy-Deep-Cycle-AGM-Battery-12-Volt-100Ah-for-RV-Solar-Marine-and-Off-grid-Applications/5013900909
Siga AGM solar battery: https://www.amp-solar.com/solaragm100/en
Solarfam AGM battery: https://www.todoensolar.com/AGM-Solarfam-12V-1500Ah-solar-battery
Varta professional battery: https://vtpower.es/en/sku/bateria-varta-dual-purpose-agm-la70-agm-12v-65ah-760a-en-278x175x190mm/
VRLA AGM battery: https://batteriesdirect.ie/product/12v-200ah-vrla-agm-battery/
West Marine AGM battery: https://www.westmarine.com/west-marine-group-24-dual-purpose-agm-battery-79-amp-hours-15020233.html
Video Reference
Counterman