AGM VS Lead Acid Battery: 12 Differences + 7 FAQs​ (2023)

Your car’s starter batteryis most likely either a flooded lead acid or anAGM battery, both of which are rechargeable battery types. However,how do a flooded lead acidand AGM batterydiffer from one another? We’ll compare AGM and lead acid batteryto see how they compare. Then, we’ll move toFAQs for more information on the car battery in this passage.

AGM VS Lead Acid Battery: 12 Differences + 7 FAQs​ (1)

AGM VS Lead Acid Battery: 12 Main Differences

It’s significant to know that the AGM battery has its source in the conventional lead-acid battery before we start comparing so that there are some similarities between them.

Let’s now compare each battery type, starting with how it operates internally.

Firstly, How Do AGM VS Lead Acid Battery Work?

Technically speaking, the base chemistry of an AGM battery and a regular lead-acid battery is identical. Both of them use lead plates and a sulfuric acid and water electrolyte, which causes a chemical reaction that resultingin the production of hydrogen and oxygen as a byproduct.They begin to diverge, from where they stand.This is how:

Flooded Lead Acid Battery

In flooded lead acid batteries, the lead plates are immersed in liquid electrolyte (FLA batteries). Gasisreleased to the atmospherefor the reason that the chemical reaction cause water to be lost. Therefore, periodic replenishing of the electrolyte levels is necessary.

AGM Battery

In the AGM battery, fiberglass mats are positioned in between lead plates. This is where the name of the battery, Absorbent Glass Mat, comes from (AGM). The AGM separatorabsorbsthe sulfation, keeping it stopped, makingitfree offreely flowing.

It hardly gets off-gassing because the AGM battery is encapsulated. The chemical reaction’s gases and electrolytes recombined. A vent also releases additional gas when necessary to maintain internal pressure (for instance, when the battery is overcharged).

Secondly, Maintenance Needs.

The Absorbent Glass Mat battery hardly needs maintenance and can be installed in lessspaces for the reason thatthere is no off-gassing other than brief venting. It is best used in vehicles with batteries in the trunk and behind the seats, as well as in places where maintenance may be challenging.

The flooded battery, on the other aspect, needs frequent electrolyte maintenance and must be placed in a well-ventilated area because it emits fumes and steam.

(Video) What is the Difference between Conventional and Absorbed Glass Mat AGM Batteries?

AGM VS Lead Acid Battery: 12 Differences + 7 FAQs​ (2)

Thirdly, Durability, Vibration and Shock Resistance.

Due to its history in the military and aircraft, AGM batteries are often more durable than flooded lead acid batteries.

The glass mat and battery plates of the AGM battery are sandwiched, which results in parts that don’t disintegrate readily. These features produce a battery that is resistant to vibration and stress, letthem famousin motorbikes and race car. Flooded battery plates can be harmed by jarring motions and strong vibrations, thus it’s important to mount them safely.

Fourthly, Mounting Flexibility and Spillage.

The AGM battery is position-insensitive and spill-proof thanks to its glass mat technology. It can be made upin a variety of ways, but never upside down. However, the flooded cell battery must always remain upright because it contains a liquid electrolyte. If leakageelectrolyte is not clear, corrosion may result.

AGM VS Lead Acid Battery: 12 Differences + 7 FAQs​ (3)

Fifthly, Internal Resistance and Power Output.

Among the numerous lead acid batteries, the AGM battery has one of the lowest internal resistances. A fresh AGM battery can have an internal resistance of around 2%, compared to the 10-15% of a new flooded lead acid battery.

Low internal resistance of battery boosts battery voltage output. Additionally, it means that less heat will be lost when the system’s electricity flows. In comparison to a flooded lead acid battery or gel, an AGM battery reacts to loading better. Lead acid variants for start-stop cars are preferred due to their ability to regulate high power demands.

Sixthly, Charging Time.

Faster charging periods are another benefit of the AGM battery’s low internal resistance. When using the same power source, the speed of a flooded lead acid battery can be up to 5 times faster than that of a lithium battery.

Seventhly, Depth of Discharge.

The depth of discharge (DoD) of AGM batteries is 80%, which is higher than the 50% DoD of flooded cell batteries. The AGM battery is therefore a good choice for deep cycle applications.

(Video) DEEP CYCLE BATTERY COMPARISON - Is Lithium really worth it?

Butnot likethe lithium-ionbattery. Itcan becompletelydischarged, neither battery type should be depleted below 50% of its capacity.

Eighthly, Temperature Tolerance.

In general, the AGM battery performs better across the board and has a propensity for good Cold Cranking Amp (CCA) ratings. When frozen, the electrolyte contained in the glass mat does not expand like a liquid. AGM batteryispreventedto be harmfulfrom lowtemperatures. Therefore, even though the battery is unlikely to function in a cold environment, it won’t break. For another, flooded lead acid batteries will freeze in the cold. The accessoriescan leak and expand, and the battery plates can ruin.

The flooded lead acid battery will consumemore acidin high temperatures, putting the battery gridsat risk of exposure to the atmosphere (the lead plates need to stay submerged).

Ninthly, Sensitivity to Overcharging.

AGM battery issubstantially less tolerant of overcharging than flooded lead acid batteries. As for thermal runaway,overchargingmakes sealed design AGM batteryismore pregnable. Even if thermal runaway is ignored,overchargingwill reduce the lifespan of an AGM battery more quickly. Therefore, to regulate the voltage and current entering the battery when charging an AGM battery, utilize a controlled battery charger.

Tenthly, Lifespan and Self-Discharge.

AGM batteries often have a longer use life than normal lead acid batteries. AGM batteries have longer use life than flooded batteries but are not in use for the reason that their low self-discharge rates.

AGM batteries can last up to seven years with proper maintenance, but a flooded battery lasts three to five years. If your automobile struggles to start, your battery may need repair.

Eleventhly, Corrosion and Sulfation.

Because it can exhaustacidic gasand is more likely to leakthan an AGM battery, flooded batteries are more susceptible to corrosion than AGM batteries.

However, if both batteries are kept in a discharged state for too long, sulfation will occur, but AGM batteries are slightly more elastic,to some degreebecauseof their slower self-discharge rate. It’s probably time to get in touch with your mechanic for a replacement battery if you see significant corrosion on your battery terminals.

Twelfthly, Cost-Effectiveness.

As a starter battery for regular autos, the flooded battery is affordable and dependable. AGM batteries can cost high to 2-3 times as much as a normal battery.

Let’s review some frequently asked questions now that we’ve known how the flooded lead acid battery and AGM battery comparison.

Battery FAQs

Here are answers to some questions on car battery:

(Video) What is better AGM or gel battery?

What Are AGM Batteries?

Early in the 1980s, the Absorbent Glass Mat (AGM) battery was created as a substitute for NiCd batteries. This kind of sealed lead acid battery (SLA battery) is spill-proof and needsno maintenance.

It is utilized in a wide range of applications, including maritime, off-grid, and high-powered sophisticated vehicles.

What’s A Flooded Lead Acid Battery?

The flooded lead acid battery (FLA battery), which has been used for more than 150 years in a variety of applications, is the most widely used type of lead acid battery.

Another name for it is a typical or conventional lead acid battery. The traditional battery is frequently referred to as a flooded battery because of the liquid acid inside. In a typical car, there’s a good chance that the battery is a wet cell.

What Is SLA Battery?

A subset of lead acid batteries is the sealed lead acid battery (SLA battery). A VRLAbattery is another name for it.

The sealed battery does not allow access to its internal compartment, unlike wet cell batteries. Instead, it controls the pressure brought on by internal chemical processes via a one-way valve.

Are Gel Batteries AGM Battery?


Since both AGM and gel batteries are sealed battery types, they are frequently confused with one another.

The electrolyte of the gel battery is silica gel, in contrast to the AGM battery, which uses a glass mat to keep its electrolyte. Due to their poor performance as starter batteries, gel cell batteries are rarely utilized in automobiles. Additionally, the gel may be harmed if overcharging occurs because of how sensitive it is to doing so.

Are EFB Batteries AGM Battery?


Enhanced Flooded Lead Acid Battery is referred to as EFB.

The EFB batteries areflooded batteriescreated to be more affordable than an AGM battery while also being an upgrade over ordinary batteries. Basic start-stop vehicles employ it.

(Video) Advantages Of AGM Batteries

Are There Lithium Car Starter Batteries?

Yes. And no.

Electric car usually uses lithium-ion battery as their power source (EVs). It functions differently from a standard lead acid battery and cannot be sufficiently recharged by the alternator found on a typical automobile engine, but lithium starting batteries are used in racing due to their lighter weight and smaller size. In addition, the lithium-ion battery can maintain its power output at any rate of discharge.

Are ordinary car starter batteries made of lithium any time soon?

Most likely not, given their high cost.

Can AGM or Lead Acid Battery Be Used as Battery Bank?


Both flooded lead acid batteries and AGM batteries can function as battery banks as well as be charged by a solar panel.

It will be less expensive to use as a flooded lead acid battery bank.

However, because the batteries must be positioned upright, they may require more maintenance and take up more room.

Because AGM batteries may rest on their sides, configuring an AGM battery bank would be simpler.

They require no upkeep as well. They will cost more than a flooded battery bank, though.

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How can you tell the difference between lead-acid and AGM batteries? ›

Basically, an AGM battery will always have a flat top, and only the negative and positive terminals of the battery will be sticking out. On the other hand, the liquid acid batteries have a removable top which is not the case with AGM batteries as they are properly sealed.

What are the disadvantages of AGM batteries? ›

Despite their many advantages, AGM batteries, just like other lead-acid batteries, also have their disadvantages. These include:
  • High production cost. Unlike the flooded batteries, AGM batteries have a higher production and manufacturing cost. ...
  • Energy issues. ...
  • Reduced capacity over time. ...
  • They are sensitive to overcharging.

Do AGM batteries hold a charge longer than lead-acid? ›

While regular lead acid batteries need a topping charge every six months to prevent the buildup of sulfation, AGM batteries are less prone to sulfation and can sit in storage for longer before a charge becomes necessary.

What should a 12 volt AGM battery read when fully charged? ›

A fully charged AGM battery should read 13.00v or above.

What happens if you charge an AGM battery with normal charger? ›

AGM batteries require a slower, more stable charge than flooded batteries and can't sustain the high charging speeds used by standard battery chargers. If you charge an AGM battery with the wrong type of charger, you will end up under or overcharging your battery.

Why is my AGM battery losing charge so quickly? ›

Whether you're using a car battery, AGM battery, lead-acid, or lithium battery, a decline in performance and faster discharge rate are usually caused by similar issues. These include battery age, over or undercharging, exposure to extreme temperatures, or sulfation.

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.

Can AGM batteries be overcharged? ›

As with all gelled and sealed units, AGM batteries are sensitive to overcharging. These batteries can be charged to 2.40V/cell (and higher) without problem; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages).

Do AGM batteries fail suddenly? ›

In time, AGM batteries (including OPTIMA batteries) may fail. Failures usually happen when a starting battery is used in a deep cycling application. In many cases, AGM batteries that seem to be bad are perfectly fine. They are just deeply discharged.

How long can an AGM battery sit without charging? ›

12 Volt Gel or AGM batteries

If kept in a charged state when unused, the common lifespan of a 12-volt Gel or AGM battery is up to six years. After five or six years of float voltage at an average ambient temperature of 25 ºC, the battery still retains 80 % of its original capacity.

Can you jump start a car with an AGM battery? ›

Jump Starting – When it comes to jump starting a vehicle with an AGM battery, whether that vehicle is a more traditional design or is equipped with Stop-Start technology, you should proceed as usual.

What voltage should I cut off AGM? ›

The truth is that any lead acid battery, be it a Gel Cell, AGM or flooded batteries such as DCBs, should be cut-off at 11.6 volts. Not doing so increases the risk of damage to the battery and if taken down deep enough into the batteries charge, will ruin the battery.

What voltage is too high for AGM battery? ›

Because they are completely sealed, AGM batteries are very sensitive to voltage (in a battery, voltage equals pressure). This means that care must be taken to not overcharge (raise the voltage too high on) an AGM battery. Most AGM batteries have a maximum voltage limitation from 14.4V to 14.65V at 70˚F.

Should I keep my AGM battery fully charged? ›

DO: Keep the battery as fully charged, as often as possible. No, these batteries do not develop a "memory" like some nickel-cadmium based batteries. Severely discharging and leaving the battery discharged can cause harm and shorten life in AGM batteries.

What is the maximum charging voltage for a 12 volt AGM battery? ›

It must not exceed 15.4 volts. If a charger/setting has been verified to not exceed 15.4 volts to a low current, the charger/setting is accept- able. (You don't need to watch the voltage every time.) 12-volt batteries should never be discharged to less than 10.5 volts under load.

Is it OK to use a trickle charger on an AGM battery? ›

Many GEL, AGM and Calcium's are better than regular lead-acid batteries but even so you should charge them back up regularly, or better still use a trickle charger (or solar panel) to keep them in top condition and extend their life.

Can you charge AGM off alternator? ›

Charging From Your Vehicle Alternator

In general car or van alternators work reasonably well with Lead Acid and AGM batteries.

Can I use a normal trickle charger on an AGM battery? ›

Different chargers have different capabilities - Although under normal conditions most 12-volt automatic battery chargers will work on an AGM battery, the battery will only charge to about 80 percent of its full capacity. Many newer battery chargers have settings specifically for AGM batteries.

How do I stop my AGM battery from overcharging? ›

How can you Avoid Overcharging AGM Batteries?
  1. AGM batteries are more likely to be overcharged in the summer. ...
  2. Use the correct voltage. ...
  3. Realize that improper use of the charger outside of your vehicle can increase the risk of overcharging. ...
  4. Regularly test your charger.

How far can you deplete an AGM battery? ›

The deep cycle A.G.M. 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 each single charge.

How many cycles do you get out of an AGM battery? ›

A standard 12 volts gel or AGM battery can carry up to 500 cycles of charge and discharge, considering that it will be charged from at least 20% battery level. Even after the six-year period is over, you might not need to replace the battery urgently as it can still be used even at 50% of its capacity.

How do you revive a dead AGM battery? ›

Connect the good battery to your “bad” AGM battery in parallel (positive to positive and negative to negative). Hook up the good battery to the charger, but ensure the charger is powered off. Once connected, turn on the charger. After about an hour, see if the AGM is warm or hot to the touch.

How do I check the health of my AGM battery? ›

You can use data you get from the battery's voltage tests to gauge its health and all you need is a lead-test meter. it should read 12.4 volts for a healthy battery. If yours is reading 0 volts, there are chances that it has had a short circuit.

Do AGM batteries overheat? ›

If your AGM battery is hot to the touch, however, then you have a potential problem. It's overheating while charging (and possibly being overused), so it needs a break. Disconnect your AGM battery and allow it to cool down before reconnecting.

What is the average lifespan of an AGM battery? ›

A properly maintained AGM battery usually lasts somewhere between three and four years, but this depends on the amount that you use it. Also, the amount that you drive your vehicle plays a role in how long the battery will last.

How long does it take to trickle charge an AGM battery? ›

Most AGM batteries hold 100 amp-hours. In this case, a 10 amp charger would be perfect, taking between two and nine hours to fully charge your battery, depending on how much it has depleted. Chargers with higher amps will charge faster, while those with lower amps will take more time.

Can an AGM battery last 10 years? ›

We can generally say an AGM battery can last two to three times as long as a flooded battery. In the commuter car example we referenced, if a flooded battery lasts three to five years, an AGM battery could last six to ten years or longer.

How do you take care of an AGM battery? ›

Keep your battery in a cool and dry place with plenty of ventilation and remember to recharge if storing for more than four months. Sulfation occurs when the sulfuric acid within lead-acid batteries reacts to form a lead sulfate on the battery's negative plates.

How do I know if my AGM battery needs replacing? ›

If a fully charged AGM battery tests more than 20 percent lower than the fully charged voltage level, it's probably due for replacement. This is typically a symptom of battery age, damage from over/under charging, or sulfation.

What is the resting voltage of 12v AGM? ›

Fully-charged, most 12-volt lead-acid batteries (including AGM products like OPTIMA batteries), should measure at least 12.6 volts.

What should a 12 volt battery read when fully charged? ›

Check the voltage of your battery using the voltmeter to help determine your next course of action. 12.6V volts or above - Your battery is healthy and fully charged.

How do you identify a lead acid battery? ›

should be recycled thru local vendors  Lead Acid/ VRLA batteries can be identified by the terms “Sealed Lead-Acid Batteries or the letters “Pb”.  Terminals on all lead acid batteries must be taped if stored prior to recycling.

Can I charge an AGM battery with a lead acid charger? ›

The nominal charge voltage for an AGM battery is 14.1-14.4V, which means that using a lead acid battery charger set to use the AGM setting will work correctly in most cases.

Do AGM batteries need a special charger? ›

The most important thing to keep in mind is that any charger or maintainer used on your AGM battery must be AGM compatible or AGM optimized.

Can I charging lead acid and AGM together? ›

Answer: You CANNOT mix and match AGM and flooded battery types on the same battery charger. You'll need a different charger for each different type of battery or it will shorten your battery life.

How many times can a lead acid battery be recharged? ›

Depending on the depth of discharge and operating temperature, the sealed lead-acid provides 200 to 300 discharge/charge cycles.

What voltage is a full charge lead acid? ›

A 12-volt lead-acid battery that is fully charged often provides a voltage of about 12.7V. If the lead-acid battery only has 20% left, it will only deliver 11.6V.

How many years does a lead acid battery last? ›

Long Service Life

Sealed lead acid batteries can have a design life of anywhere from 3 – 5 years all the way up to 12+ years depending on the manufacturing process of the battery.

Can I use a trickle charger on an AGM battery? ›

Many GEL, AGM and Calcium's are better than regular lead-acid batteries but even so you should charge them back up regularly, or better still use a trickle charger (or solar panel) to keep them in top condition and extend their life.

Can AGM battery be fully discharged? ›

The deep cycle A.G.M. 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 each single charge.

How long should an AGM battery hold a charge? ›

Most AGM batteries hold 100 amp-hours. In this case, a 10 amp charger would be perfect, taking between two and nine hours to fully charge your battery, depending on how much it has depleted.

Can you charge AGM battery with alternator? ›

Charging From Your Vehicle Alternator

In general car or van alternators work reasonably well with Lead Acid and AGM batteries.

What voltage should I charge AGM battery? ›

Deep Cycle AGM:- AGM batteries should be charged using a charger with a mode switch for AGM type batteries. It is recommended to use a charger, current limited to 20% or 0.2C of the batteries capacity at a charging voltage of between 14.6 – 14.8V following deep cycle use, or 13.6V – 13.8V for standby use.

Can you jump start an AGM battery? ›

Your One-Stop Solution for AGM Service

As mentioned above, jump starting AGM batteries is very straightforward. That said, our Booster PAC and Jump-N-Carry traditional jump starters use AGM batteries in them and are legendary for their power and durability.

What is the best way to charge an AGM battery? ›

The best way to charge an AGM battery is with a charger designed for that specific purpose. When charging, remember that AGM batteries must not be charged over 14.8 volts in most cases. The manufacturer of your particular battery probably has a specification and guide sheet to set some specific rules and guidelines.


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