What Is The Difference Between An AGM Battery And A Standard Battery?

What Is The Difference Between An AGM Battery And A Standard Battery

Batteries are a portable source of energy and power supply. Most electronic devices and automobiles require a battery that acts as the secondary source of power. Foremostly, the lead-acid batteries were the only form of battery to be used. But with time there are a lot of batteries produced due to constant research and development. AGM batteries are one of them.

To know the effectiveness, we should know what is the difference between an AGM battery and a standard Battery. Because even though the basic principle of electricity production is the same in batteries, the electrochemical reactivity. The construction, electrodes, and form of electrolytes are different.

In this article, we shall get to know the ins and outs of the two battery types. It will be helpful for those who are planning to get one for their requirement.

Comparison Between AGM battery and Standard battery

In the following chart, we shall look into the prime differences between the AGM batteries and the Standard Batteries.

AGM Battery Standard Battery
Electrolytes in the AGM batteries are absorbed by the glass mats.Electrolytes are directly poured into the cell chambers.
Very thin lead plates are used as electrodesSlightly thicker lead plates are used in the form of blocks.
Almost pure Lead is used as ElectrodeLead Alloys are used as Electrodes.
The cells are of Lead plates, AGM separator, and grid closely packed.The cells are made of only the electrodes and flooded electrolytes
Electrolytes remain in absorbed form in the fiberglass mat.Electrolytes remain in the liquid from inside the cell chambers.
AGM batteries can withstand very low temperaturesDegrades the effectiveness in low temperature.
AGM batteries are completely sealed and spill proofStandard Lead-Acid batteries are not spill-proof or sealed. 
No refilling of acid/distilled water is requiredRequires regular refilling with the acid.
The battery is made to be anti-vibration affectiveVibration causes an interruption in power development.
Depth of discharge if only 50%Depth of discharge can be up to 80%
The higher charge holding capacityThe relatively lower charge holding capacity
Negligible Sulfation rateRequires regular desulfation
Higher cold-cranking ampsLower cold-cranking amps
More cranking power and higher amp-hour(Ah)Relatively lower cranking power and little amp-hour(Ah)
Charges very quickly using a compatible chargerCharging takes very much time
Sensitive to overchargingNot sensitive to overcharging
Relatively expensiveVery Cost-effective

Are there really any differences between an AGM battery and a standard battery?

In this section, we shall learn in-depth about the differences between AGM and Standard batteries.

Electrolyte Formation

In the AGM battery, the electrolytes are absorbed by the absorbent glass mats. The AGM separators remain sandwiched in between the positive and negative electrode plates. Therefore, there remains no free electrolyte in the cell chamber or the entire battery compartment.

On the other hand, in standard Lead-Acid Batteries, the liquid form of the electrolyte is poured. There are six cell chambers inside the battery where the level of electrolytes in every chamber should be maintained properly to get the required voltage. For keeping the electron composition in the electrolyte regular refilling of distilled water is mandatory.

Electrode Types and formation

In the Absorbed Glass Mat batteries (AGM) the electrodes are compactly sandwiched together in between the AGM separator. The positive and negative electrode plates are tightly packed together because the plates are very thin in the width.

In the standard lead-acid batteries, the Lead plates are used in the form of blocks. They have higher width comparatively. Moreover, in the cell chambers, the lead plates are kept separately inside the cell chambers and are connected using the series connection.

Material and purity of the Electrodes

In the AGM batteries, pure lead plates are used as the electrodes. They are closely packed together to form a series of plates with the AGM separator. 

The standard lead-acid batteries use thicker and impure lead electrodes. Most of the time lead alloys are used as the electrodes. Calcium or magnesium traces are used along with lead to make the electrode. This helps to induce the flow of electrons from the electrode to the electrolytes. As a result better flow of electricity and voltage output is seen.

Cell Construction

The AGM battery has six cells like other batteries. But the assembly of the cells is quite different. Each cell of the AGM battery has a packed structure. There are two electrodes with positive and negative Lead plates, an AGM separator, and the grids. All these combined make the cell. The electrolytes get absorbed by the glass mats sandwiched in the middle.

This structure makes the battery completely free of liquid electrolytes. As a result, it becomes spill proof and vibration-resistant.

On the contrary, in the standard battery, the cell chambers are flooded with liquid electrolytes. No grids are used. And the lead blocks are poured inside the electrolyte which acts as the positive and negative electrolytes. All the cells have an opening end to the lid of the battery. That is why standard batteries are not spillproof and vibration resistant.

Temperature Resistivity

All electrochemical batteries are sensitive to temperature fluctuation. Both hot and cold temperatures compared to the optimum cause a negative impact on the effectiveness of the battery.

The Absorbed Glass Mat batteries have better temperature withstanding capacity. It is because of the formation of the cells inside the battery. The electrolytes being absorbed by the glass mats do not have much difference caused by the temperature fluctuation.

In the standard batteries, the electrolytes remain in liquid forms. The temperature has a greater impact on this state of the matter. It interrupts the flow of free electrons throughout the cell as overall voltage decreases rapidly.

Battery Container and Sealing

The AGM batteries are contained very securely inside the prime container. It is completely sealed to secure the battery from external impacts. Besides, you cannot open up the battery to do some modifications which shall void the warranty. This construction makes the battery very vibration-resistant.

One of the forms of AGM batteries, the Optima batteries have a spiral form of cells. These are isolated from each other. Apart from the two terminals of the battery, there are no further entry points in the battery. These optima batteries are very popular for extreme vehicles such as ATVs, dirt bikes, and 4wd vehicles.

The standard batteries on the other hand have an insecure battery casing. There are six-cell openings on the lid of the battery. It is because refilling of the cell chambers with distilled water to keep the electron movement free in the electrolyte.

Depth of Discharge

The AGM batteries have a higher depth of discharge rating. It means you cannot allow your AGM battery to get discharged below the 50% limit. It will actively damage the battery performance. Or even worst-case scenarios, the battery can be dead and fail to restore due to over-discharge.

Standard batteries on the other side have a 20% depth of discharge rate. These batteries have better restoration power. Changing the electrolyte, charging in high voltage can easily revive the standard batteries. Therefore, you can use the maximum effectiveness of the standard batteries.

Sulfation Rate

Sulfation is a process through which free sulfur accumulation occurs from the electrolyte which is Sulphuric Acid.

The AGM battery has a negligible rate of Sulfation because there is no free liquid form of electrolyte available in the battery. That is why the performance of the AGM batteries never drops down due to over-sulfation. 

On the other hand, the standard batteries have a very high Sulfation rate. Because, due to the free liquid form of electrolytes, the sulphuric acid releases the Sulfur at some time of the electrochemical process. That is why regular desulfation procedures need to be followed to keep the battery running.

Cold-Cranking Amps

Cold Cranking Amps or CCA is the ability of the battery to produce specific amperage of power in 0F for 15seconds. The voltage should be maintained at 9.5-10V.

The CCA rating in the AGM batteries is very high. There are many batteries with CCA over 1000 to support heavy vehicles. Besides, you will get a very marginal error from the labeled and practical result of the CCA output in AGM batteries. 

In the standard batteries, the CCA rating is comparatively lower. Most of the conventional lead-acid batteries fail to produce the labeled amount of cranking amps at a lower temperature.

Over-Charging Sensitivity

AGM batteries are very sensitive to overcharge. It may damage the endurance of the battery. Higher voltage from the charger may also cause degradation of the battery. You must strictly use the automated smart chargers for charging the batteries. It will keep the voltage and amp input on track.

But, standard batteries have no limit to overcharging. It can withstand higher voltage input without any difficulties. But the amp input should be limited to 2-10 amps for charging the battery. You can easily use the normal dumb chargers to charge the standard batteries.

Refilling the cell chambers

The AGM batteries need not be refilled with distilled water from time to time. It is a completely maintenance-free battery. The standard batteries on the other hand require regular refilling of distilled water or sometimes with electrolytes. It is done to maintain the flow of electrons in the electrolytes.

AGM vs Standard battery charging

Charging the batteries on a regular basis is a must to keep the battery health up. Depth of discharge of the batteries should be kept in mind. AGM batteries are technologically advanced than standard batteries. Therefore the charging systems of the batteries are very different.

The AGM batteries are sensitive to overcharging. You have to keep track of the voltage reading constantly while charging. You must use the standard automated smart charger to charge the AGM batteries. These chargers have a specific charging profile available for the AGM battery. 

Besides, if you want to charge the AGM battery on a regular basis, you have to set the amp between 2-10amp. For quick charging, you can set the amperage to a maximum of 20 amp. It will quickly charge your battery and will degrade the battery health on the other side. It takes 5-6 hours to completely charge the AGM battery. You should not charge the AGM batteries over 90% SoC.

The standard batteries can be easily changed by any sort of charger. Besides, the alternator of the vehicles can effectively charge the battery. Since the depth of discharge of the standard batteries is 20%. You can select the specific charging profile from the smart battery charger to charge the battery.

Moreover, you can easily use the normal chargers to charge the standard batteries. As it is not sensitive to overcharging you need to regularly check the voltage reading on the charger. It takes 8-10 hours to charge a six-cell standard battery.

Can you use a standard battery charger for the AGM battery?

You can use a standard battery charger to charge the AGM batteries. But most of the standard chargers do not have to limit power or an auto shut-off system. The AGM batteries are highly sensitive to overcharging. Overcharging degrades the cells of the battery and overall battery health.

That is why if you want to use the standard battery charger you must use an external multimeter or voltmeter to the voltage reading on track. It takes almost 9-10 hours to completely charge the AGM batteries using normal chargers. Therefore, you have to check the voltage reading after every hour. The SoC of the battery should not exceed a 90% rating. 

Standard batteries have some problems. You cannot control the amperage input in the standard charger. Besides, the charger sometimes inputs high voltage to the AGM battery. For all these reasons, it is better to use a smart battery charger to charge the AGM batteries. Smart chargers will give you total control of the charging process.

You can select the required amp input to the battery. There is a dedicated AGM charging profile in smart chargers. Moreover,  some chargers have an auto shut down the system to prevent overcharging your battery. 

Does AGM battery last longer than standard batteries?

In reality, AGM batteries do last longer than standard batteries. But there are facts to be noted for these two types of batteries.

Absorbed Glass Mat batteries have a life expectancy of 4-5 years. With regular charging and maintenance, you can extend the battery life up to 6-7 years. Though the AGM batteries are maintenance-free, you can keep the terminals clean and perform desulfation to increase battery health.

The standard batteries on the other side have shorter longevity than AGM batteries. It lasts up to 2-3 years based on the warranty period. You have to do regular maintenance work to keep the battery healthy. 

Regular flooding of the cell chambers with acid or distilled water keeps the battery health checked. You can disassemble the battery to do some internal repairing. Doing these will prolong the battery health to 4-5 years of maximum usage.

How can you tell the difference between AGM and standard batteries?

It is difficult to visually detect the difference between the AGM batteries and the Standard batteries. But following some series of actions the differences can be detected.

The battery casing of the AGM battery is completely sealed shut. There are no openings on the edges or the corners of the AGM batteries. Besides, in standard batteries, there are six-cell openings present on the standard flooded batteries. This is absent in the AGM battery.

By shaking the battery you can differentiate the AGM batteries from the standard flooded batteries. There are liquid electrolytes present in the standard batteries. You can feel the movement of the liquids inside the battery.

But, shaking the AGM battery will not create any sort of feeling of the liquid inside the cell chambers. It is because the electrolytes in AGM batteries remain in an absorbed form.

AGM batteries can come in rectangular shapes or cylindrical shapes. But, Standard batteries only have rectangular block shapes.

Is an AGM battery better than a standard battery?

An AGM battery is far better than that of a standard battery. These batteries are spill proof, vibration resistant. You can install AGM batteries in extreme off road sports vehicles. But doing the same with flooded batteries is not recommended.

AGM batteries have higher charging capacity, higher power delivery capacity. This means the effectiveness of the standard battery is lower than that of the AGM batteries. Besides, AGM batteries are long-lasting and can be charged very quickly. Therefore, we can conclude by saying that the Standard batteries lag behind the AGM batteries in many aspects.

How to tell your battery is AGM or standard?

Doing a visual inspection will let you know that your battery is AGM or standard. On the standard battery lid, there will be present six-cell opening caps. These are absent in the AGM batteries. Shaking the batteries will reveal that standard batteries have liquid electrolytes inside the cell chambers but AGM batteries do not. Last but not least, many AGM batteries now come in the cylindrical shapes of the cells.

Final Words

There are a lot of major and minor differences between the AGM and Standard batteries. It is important for you to know the differences between these two. Because you want to buy a new battery or replace the existing battery. You must understand clearly what is the difference between an AGM battery and a standard battery.

This article has covered the major and as well minute aspects of the differences between the two batteries. It will help those who are not professional or new in the field of batteries. Lastly, a clear concept of the AGM battery and Standard will help you pick the best-suited one for your requirement.

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Marcelo Araujo-Xavier

Hi, Marcelo Araujo-Xavier is here! I am the author of Batteryhint. I have been working in the battery industry for over 20 years and have a passion for helping people find the best battery for their needs. I have personally tested and reviewed hundreds of different batteries. I'm certified by the International Association of Automotive Battery Manufacturers. I have always been interested in batteries and how they work, so I decided to start this website to share my knowledge with others. I hope you find the information on this website helpful and informative. I will be regularly updating this website with new resources, If you have any questions or comments, please feel free to contact me. I would love to hear from you and help you find the best battery for your needs.

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