Are AGM Batteries Better Than Lead-acid? AGM Battery Vs. Lead-Acid Battery

Are AGM Batteries Better Than Lead-acid? AGM Battery Vs. Lead-Acid Battery

In this blog, we’ll contrast AGM and lead-acid batteries to see how they compare.

Two common types of batteries are traditional lead-acid and absorbed glass mats (AGM), which you’ll probably notice when looking for a new battery. Which battery type should you pick for your car and what makes these two different types of batteries different?

High energy output can be produced by AGM batteries, and they can keep producing that energy for longer. Unlike the conventional flooded lead-acid battery, which only offers a brief burst of energy, they can be used to power electronics for a long time.

In this article, we’ll compare lead-acid and AGM batteries side by side. We have compared Gel Battery Vs Lead Acid Battery, Alkaline Battery vs Lead Acid Battery, and Lithium Vs Alkaline Batteries. Let’s begin.

What is a Lead-Acid Battery?

For a long time, cars have used lead-acid batteries. Six series-connected cells make up an automotive lead-acid battery. Each cell has insulating separators between its negative (lead) and positive (lead dioxide) plates. A sulfuric acid/water solution (electrolyte) fills the battery.

Electrons flow from the negative plate to the positive plate as a result of the chemical reaction between the plates and the acid solution, producing electrical energy. This chemical reaction results in approximately 2.1 volts being produced by each battery cell. The battery generates a total of roughly 12.6 volts because the cells are wired in series.

Are AGM Batteries Better Than Lead-acid? AGM Battery Vs. Lead-Acid Battery

Lead-acid batteries produce hydrogen and oxygen gases while they are being charged, and this needs to be mentioned. Because of this, these batteries have vents that allow the gases hydrogen and oxygen to escape.

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  • They perform better, that is. they convert energy into electricity more efficiently).
  • Under harsh conditions like heat, cold, moisture, and dust, lead-acid batteries perform better for longer.
  • They possess a greater power density, i.e. they can store more energy in smaller packages).
  • Lead-acid batteries can be used anywhere because they safely store energy in chemical form.
  • Lead-acid batteries are safe to store and kind to the environment.
  • Simple, durable, and easy to fix.
  • They are lightweight, making them simple to transport.
  • Repairing lead-acid batteries is not expensive.
  • Batteries made of lead acid are very inexpensive.
  • versatile and suitable for a wide range of uses.


What is An AGM Battery?

Are AGM Batteries Better Than Lead-acid? AGM Battery Vs. Lead-Acid Battery

AGM batteries are standard equipment in a large number of recent models of vehicles. On vehicles with stop-start systems, the technology is particularly widespread. You can also decide to switch out the standard lead-acid battery in your car for an AGM battery produced by aftermarket companies like Odyssey Battery.

AGM batteries are similar to traditional lead-acid batteries in that they have six cells, each of which contains plates with insulating separators. The main distinction is that an AGM battery’s separators are made of an absorbed glass mat, a substance that soaks up the battery’s acidic solution. An AGM battery has another distinction in that its cells are compressed to maintain the acid solution’s pressure between the plates.


  • There is no upkeep required. Neither battery charging nor battery replacement will be a concern for you. You are able to continuously operate a car or a truck.
  • You will be able to save money. AGM batteries are less expensive to buy than traditional batteries.
  • AGM batteries won’t damage the environment. None of them cause air pollution.
  • Longer periods of time can be spent using AGM batteries. You can keep your car or truck running for hours on end. They might be useful for starting your vehicle.
  • Charge your AGM batteries quickly and easily. You can quickly recharge batteries using any of the many available chargers.
  • AGM batteries have higher levels of dependability than regular batteries.
  • They won’t break down if you don’t use them frequently, and they’ll function just as well.
  • Extreme temperatures won’t harm them.
  • Environmentally friendly AGM batteries are available. They can be discarded without damaging the environment.
  • Furthermore, the deep cycle rating of AGM batteries is very good. This implies that you can utilize them repeatedly.


  • In comparison to flooded batteries, AGM batteries cost a little more.
  • They run down more quickly than alkaline batteries
  • AGM batteries don’t have nearly as much capacity as alkalines
  • produce more heat
  • AGM batteries don’t last as long when used in low-temperature applications
  • AGM batteries make an annoying grinding sound when you remove them from your radio or other electronic devices
  • Heavier and bulkier
  • They may explode
  • Must be recharged more often.
Are AGM Batteries Better Than Lead-acid? AGM Battery Vs. Lead-Acid Battery

Are AGM Batteries Better Than Lead-acid?

As opposed to conventional lead-acid batteries, AGM batteries have a number of advantages. The primary advantages include:

How They Work

In terms of base chemistry, an AGM battery and a regular lead-acid battery are equivalent. They both use lead plates and an electrolyte solution of sulfuric acid and water, and they undergo a chemical reaction that results in the production of hydrogen and oxygen as a byproduct. They begin to diverge, though, at this point.

The flooded lead acid battery (FLA battery) uses lead plates submerged in liquid electrolytes. The gases produced during its chemical reaction are vented into the atmosphere, causing some water loss. As a result, the electrolyte levels require regular replenishment. Learn How Do Lead-acid Batteries Work?

Using fiberglass mats in between lead plates, the AGM battery operates. It’s where the battery gets its name, Absorbent Glass Mat (AGM). The electrolyte solution isn’t free-flowing because the glass mat wicks it and keeps it suspended.

Because the AGM is a sealed battery, there’s minimal to no off-gassing. The electrolyte and the gases formed during the chemical reaction reacted. And if there is excess gas (such as when the battery is overcharged), a vent releases it to maintain internal pressure.

Maintenance Needs

The AGM battery is maintenance-free and can be placed in more enclosed areas as there’s no off-gassing except for the occasional venting. It works best in cars with batteries in the trunk and under the seats, as well as in places where maintenance may be challenging.

On the other hand, the flooded battery requires regular electrolyte servicing and needs to be in a well-ventilated area as it releases gases and steam.

Are AGM Batteries Better Than Lead-acid? AGM Battery Vs. Lead-Acid Battery

Durability, Vibration and Shock Resistance

The AGM battery tends to be built harder than the flooded lead acid battery, as it originally served military and aviation use. The AGM battery’s sandwiched design of glass mat and battery plates results in parts that are durable. This structure results in a battery that’s shock and vibration resistant — making them favorites in race cars and motorcycles.

Forceful movements and heavy vibrations can damage flooded battery plates, and they need to be mounted securely to minimize these effects.

Mounting Flexibility and Spillage

The glass mat technology in the It is spill-proof and position-insensitive thanks to the AGM battery. You can mount it in many configurations (just don’t turn it upside down). However, the flooded cell battery has a liquid electrolyte, so it must always be upright to prevent spills. If spilled electrolyte is not cleaned up, corrosion may result.

Internal Resistance and Power Output

The internal resistance of AGM batteries is among the lowest of all lead acid batteries. A new AGM battery can have an internal resistance as low as 2%, compared to the 10-15% of a new flooded lead acid battery. A higher lead acid battery voltage output results from low internal resistance.

Additionally, it means that less heat will be lost as the system’s power is transferred. Like flooded lead acid or gel batteries, AGM batteries react to loading better. They can handle high power demands so well that start-stop vehicles almost exclusively use this lead acid variety.

Charging Time

Are AGM Batteries Better Than Lead-acid? AGM Battery Vs. Lead-Acid Battery

Faster charging times are another benefit of the AGM battery’s low internal resistance. Not as fast as a lithium battery, but up to 5x more than a flooded lead acid battery, when using the same power source.

Depth of Discharge

AGM batteries have an 80% depth of discharge (DoD), which is better than the 50% DoD offered by a flooded cell battery. The AGM battery is thus well suited for deep-cycle applications. Nevertheless, unlike the lithium battery, which can be fully discharged, it is not advised to discharge either battery type below 50% of its capacity. Read How Do You Charge a Lead-acid Battery?

Note: How much battery capacity can be safely discharged without causing damage is indicated by the depth of discharge.

Temperature Tolerance

The AGM battery generally performs better in all temperatures and tends towards good ratings for Cold Cranking Amps (CCA). The electrolyte that is contained in the glass mat does not expand like a liquid when it is frozen. This makes AGM batteries resistant to cold weather damage. Therefore, even though the battery is unlikely to function in a frozen environment, it won’t break.

On the other hand, flooded lead acid batteries will freeze when it is cold. The battery plates may break, and the cases may enlarge and leak. The flooded lead acid battery will experience greater electrolyte evaporation in extremely hot conditions, putting the lead plates—which must remain submerged—at risk of atmospheric exposure.

Sensitivity to Overcharging

Flooded lead acid batteries are much more tolerant to overcharging than AGM batteries.

AGM batteries are more vulnerable to thermal runaway condition because they are sealed, and overcharging can cause this condition to occur. Overcharging will reduce an AGM battery’s lifespan more quickly, even if thermal runaway is ignored. So, when charging an AGM battery, use a regulated battery charger to control the voltage and current going into the battery.

Note: A battery enters thermal runaway when it produces more heat than it can expel. In extreme situations, the battery may melt, dry out, release toxic chemicals, spark fires, or explode. Nearby batteries will be affected and may result in a domino effect.

Are AGM Batteries Better Than Lead-acid? AGM Battery Vs. Lead-Acid Battery

Lifespan and Self-Discharge

In general, AGM batteries last longer than typical lead-acid batteries. AGM batteries outlast their flooded counterparts in standby time due to their low self-discharge rates. See How Long Do Lead-acid Batteries Last?

AGM batteries can last up to 7 years with proper maintenance, whereas flooded batteries typically last 3-5 years. If your car struggles to start, your battery may need repair.

Corrosion and Sulfation

The flooded battery is more prone to corrosion than the AGM battery because it can vent acidic steam and is likelier to spill and leak electrolyte liquids.

However, both batteries will suffer sulfation if left in a state of discharge for too long. AGM batteries, however, are a little more resilient, in part because of a slower self-discharge rate. If you see extensive corrosion on your battery terminals, it’s probably time to contact your mechanic for a replacement battery.


The flooded battery is cost-effective and reliable as a starter battery for standard cars. AGM batteries can be up to 2-3 times more expensive than conventional batteries.

Which is the Best Choice for Your Vehicle?

Which type of lead acid battery should you choose for your vehicle: lead-acid or AGM? You should pick an AGM battery as a replacement if your car already had one from the factory. In contrast, you can either stick with the lead-acid battery that came with your car or upgrade to an AGM battery if it was the original design.

In almost every respect, AGM technology outperforms lead-acid technology. The only drawback is that lead-acid batteries tend to be less expensive than AGM batteries. Therefore, a traditional battery might be the best option if you’re on a tight budget or have a car that you don’t intend to keep for a long time. If not, getting an AGM battery is typically worth the extra money.

Conclusion: AGM Battery Vs. Lead-Acid Battery

Finally, even though AGM has nearly completely replaced Lead Acid batteries, the majority of vehicles still start with Lead Acid batteries today. Although they are both of the same general battery types, they differ in certain ways. We have listed the differences between AGM batteries and Lead Acid batteries.

We now understand how AGM batteries and submerged lead-acid batteries compare, so if you have any additional inquiries, please get in touch with us.


Are AGM Batteries Worth the Extra Money?

From that standpoint, it at least seems logical because many AGM batteries will last two to three times as long as their flooded counterparts. AGM batteries make even more sense when the safety advantages are added on top of the performance advantages.

How Long Do AGM Batteries Last Compare to Lead-acid?

AGM batteries generally last longer than standard lead acid batteries. AGM batteries last longer than flooded batteries when not in use because of their low self-discharge rates. While flooded batteries typically only last 3-5 years, an AGM battery with proper maintenance can last up to 7.

What Causes AGM Batteries to Fail?

If the charge level of a fully charged AGM battery is less than 20% of a fully charged voltage level, the battery could have been damaged by sulfation, overcharging, or undercharging. It can be improved using a desulfation device or by just replacing the battery.

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