Marine Battery Vs AGM

Marine Battery Vs AGM

Have you wondered why people compare marine battery vs AGM?  Car owners know more about these types of batteries.

It is either you have a marine battery or an AGM battery. For people who want to know the differences between these batteries, we have made it easier for you.

Marine Battery Vs AGM
Marine Battery Vs AGM

Marine battery vs AGM.

Are marine batteries standard or AGM?


In this article, we highlighted the differences and similarities of marine battery vs AGM.

We expanded the article to FAQs to help you understand what the two batteries can do for you.

Before we make our comparison, you should learn that AGM batteries have their roots in the traditional lead acid batteries. This makes them work in similar ways.

The standard lead acid battery and AGM are technical the same if you consider their chemistry base.

The batteries use an electrolyte (mix of water and sulfuric acid) and lead plates to produce oxygen and hydrogen as a byproduct.

What is the difference between AGM and marine batteries?

Here’s what to know about the marine batteries:

Flooded Lead Acid Battery

The flooded lead acid battery (FLA battery) uses lead plates that are submerged in liquid electrolyte.

It produces gases vented into the atmosphere that cause water loss.  This makes the battery to get regular replenishment with electrolyte levels.

AGM Battery

This battery uses fiberglass mats kept between lead plates. AGM means Absorbent Glass Mat.

Why are AGM batteries so expensive?


AGM wicks its electrolyte solution and suspends it not to freely flow. The battery is sealed and features no gassing.

The gases the battery produce are recombined with the electrolyte.

When the battery is overcharged or there is excess gas, a vent makes it happen to support internal pressure.

Are AGM batteries good for marine?

Marine Battery Vs AGM
Marine Battery Vs AGM


When it comes to the marine battery vs AGM, the latter is maintenance fee. You can place it in enclosed places due to its no off-gassing feature.

AGM battery is suitable for vehicles whose batteries are under seats, in trucks, or locations that make maintenance difficult.

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However, flooded battery need regular electrolyte filling. It should be placed in well-ventilated places because it releases steam and gases.

How can you tell if a battery is AGM? 

The Absorbent Glass Mat batteries are more durable than the marine batteries. AGM products originally worked for aviation and military uses.

Its sandwiched structure of battery plates and glass mat ensure that the components don’t break away easily.

The configuration helps the battery resist vibration and shock. It makes it popular among race motorcycles and racecars.

However, heavy vibrations and forceful movements can affect the flooded battery plated. You should mount these batteries firmly to reduce the effects.

What is the advantage of an AGM battery?

The AGM battery makes use of the  glass mat technology that is spill-proof and position insensitive. Users can mount the battery in different configurations.

However, when it comes to using  the flooded cell battery with a liquid electrolyte, mount it  upright to avoid spills.

If you do not clean up spilled electrolyte, it can cause corrosion.

Power Out and Internal Resistance

The AGM battery has an internal resistance considered  among the lowest of the various lead acid batteries.

A new flooded acid battery has an internal resistance of 10-15%,while a new AGM battery can be as low as 2%.

Increased battery voltage output translates to low internal resistance.  This offers a reduced loss of heat when power moves through the system.

The AGM models responds faster to loading than gel batteries or flooded lead acid. AGM handles large power supply better than marine batteries.

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


AGM battery faster charging times happen because of its low internal resistance. However, the battery is not faster than the lithium battery.

It works 5x better than the flooded lead battery when you use the same power supply or source.


Are AGM marine batteries worth the money?


AGM batteries offer an 80% depth of discharge (DoD) that is more effective than what the flooded cell battery provides at 50% DoD.

Marine Battery Vs AGM
Marine Battery Vs AGM

AGM battery  is better suited  to deep cycle applications.  However, we do not recommend you to discharge either battery type below 50% of its capacity.

You can do that to the lithium battery, which can be fully discharged.

Depth of Discharge displays how much battery capacity can be discharged without damaging it.

Temperature Tolerance

If you want to consider marine battery vs AGM in terms of temperature tolerance, the AGM battery performs better.

The battery works great in all temperatures and ranks well in the Cold Cranking Amp (CCA) ratings.

The battery’s electrolyte held in the glass mat doe not expand like a liquid while frozen.  The feature makes AGM batteries resistant to cold weather damage.

You can use the battery in a cold environment without damage.

Flooded lead acid batteries will freeze in the cold.  You will see the battery plates crack in cold weather, and the cases can end up expanding and leaking.

The flooded lead acid battery can evaporate its electrolyte in extreme heat, and risk the battery plates to suffer from atmospheric exposure.

The disadvantages of AGM batteries


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The flooded lead acid batteries can tolerate overcharging than AGM models.   AGM batteries are sealed which them less tolerant to thermal runaway.

This can could result due to their overcharging  You end up shortening the lifespan of AGM batteries if you try to discount thermal runaway.

When you want to charge the AGM batteries, use regulated battery charges for controlling current and voltage going into them.

What causes AGM batteries to fail?


Comparing marine battery vs AGM should deal with thermal runaway strength. This happens when a battery ends up with more heat than it can dissipate.

When this happens, it quickly dries out and melts. The battery emits toxic chemicals that could cause an explosion or fire in extreme cases.

Also, a nearby battery can get affected during thermal runaway and cause a domino effect.

How many years do AGM batteries last?

The marine battery vs AGM argument goes in favor of AGM batteries that last longer than marine acid batteries.

AGM has low self-discharge rate that makes it last longer than the flooded batteries when they are idle.

If you maintain your AGM battery, it can last up to seven years. The flooded batteries can last between 3-5 years.

The reason you know about a problem is when your car would not start immediately.

Marine Battery Vs AGM
Marine Battery Vs AGM

Salvation and Corrosion

The AGM battery is more resistant to corrosion than the flooded battery. The reason for this is the flooded battery’s vent acidic steam.

The vent makes it prone to leaking and spilling its electrolyte fluid. Nevertheless, both batteries are prone to salvation when they are left in state of discharge.

The marine battery vs AGM can be evaluated under salvation.  The AGM battery is more resistance because of its slow-self discharge rate.

You should meet your mechanic if you notice extensive corrosions on the terminal.


If you a reliable and cost-effective starter battery, use the flooded battery for standard cars.  However, you spend more when buying any AGM battery.

  Lithium Car Starter Batteries

The lithium ion battery is mainly used to power electric vehicles (EVs). The battery works differently than the standard lead acid battery.

The battery can’t be fully charged by the alternator fitted with a regular car engine. We have lithium starter batteries for lighter weight and compact size in motorsports.

The lithium ion battery offer constant power over any rate of discharge. The battery is more common among car users because it is cheap.


 Usage of AGM Or Lead Acid Batteries As A Battery Bank?

You can use lead acid deep cycle and AGM batteries as your battery bank to charge up your solar panels.

Meanwhile, the flooded lead acid battery bank has cost-effective setup. This means you need require regular maintenance.

The batter may take up more space because it must sit upright. You can easily configure your AGM battery because it lies on the sides.

The battery is maintenance –free and can cost more than a flooded battery bank.


Do I really need an AGM battery?

Most cars on the road don’t need an AGM battery. The reason is these batteries won’t stay in the fringes for long.

People who use AGM batteries are people who use the highways. Most of them are not aware they use such batteries.

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Can you jump start an AGM battery?

Yes, you can jump start your car with an AGM installed.  However, the battery may not charge on the alternator.

The car would not star again if you decide to stop.

Can you replace a AGM battery with a normal battery?

When your AGM battery die, you have two options. You can decide to replace the battery with another AGM or go back to a normal battery.

Keep in mind that these two battery designs have different charging characteristics, so make sure you use the correct charger or tender for your battery.

What is AGM battery vs standard? 

AGM batteries can start an engine more than 60,000 times than what you get from any conventional battery.

AGMs recharge faster than standard batteries. Nevertheless, starting your engine depletes your battery only a small amount before the alternator takes over.

Which is better EFB or AGM battery? 

An EFB battery can handle a temperature increase at 50°C and absorb 52 percent more energy than AGM battery.

EFB will last 52 percent longer than an AGM battery in high-temperature environments.

Will my alternator charge an AGM battery?

The alternator-based charging systems are for flooded lead-acid batteries. The alternator will not work optimally with AGM batteries.

With the default charging profile, these systems risk both over- and under-charging an AGM battery, which is much more sensitive to charge voltages and staging.


We can compare the marine battery vs AGM in our FAQs.


What’s An AGM Battery?

We said that AGM means Absorbent Glass Mat. The battery was created as an alternative to the NiCd battery.

AGM battery comes as sealed lead acid battery (SLA) that features spill-proof and maintenance-free.

The battery is used in different applications, including advanced vehicles.

What is A Flooded Lead Acid Battery?

You find the flooded lead acid battery (FLA battery) around than AGM batteries. It has been in existence longer than the AGM battery.

FLA battery is the conventional or standard lead acid battery called the wet cell batteries because they have liquid electrolyte.

Most car users have used the wet cell battery.

What are Sealed Lead Acid Batteries?

SLA are known as the sealed lead acid battery. The battery  is a subset of lead acid batteries.

Most people called the battery the Valve Regulated Lead Acid battery (VRLA battery). This sealed batter does not allow internal compartment access.

SLA has a one-way valve to regulate pressure due to internal chemical reactions.

 Is A Gel Cell Battery An AGM Battery?

A gel cell battery is not an AGM battery. The two products are sealed battery models.  The AGM battery uses a glass mat to contain its electrolyte.

The gel battery uses a  silica agent to suspend its electrolyte in gel form. This type of battery is not often used in cars.

Gel batteries are prone to overcharging and damage could happen when overcharged.

Can I replace EFB battery with AGM?

The meaning of EFB is Enhanced Flooded Lead Acid Battery.  It is not an AGM battery. This battery comes as a flooded battery.

It is an improvement over conventional batteries, but cheaper than an AGM battery. The battery is mostly use in basic start-stop vehicles

Are all deep cycle marine batteries AGM? 


People who use starting batteries experience quick bursts of power when they start their car engines.

The deep cycle battery delivers steady power over an extended period of time.  We mostly find these batteries in backup technology.

You can see it in marine vehicles or as alternative energy storage. In fact, the battery is also called a marine battery because that’s one of its most common uses.

Every lead acid battery, including flooded, gel cell, or AGM is used I any deep cycle purpose.  All types of lead batteries are deep cycles too.