What is the Difference Between AGM and GEL Batteries?

AGM (Absorbent Glass Matt) Battery and Gel Battery are often mistaken to be the same. Both batteries possess similar traits such as having deep-cycle capabilities, non-spillable design and both can be used in different orientations. The two battery types are also known for their low self-discharge, low-maintenance and vibration-resistant characteristics. However, AGM and Gel are two distinctly different types of batteries.

Through this post, we’re comparing the two battery types in order to help you see which one suits your needs.

CONTENTS

1. Overview on the key difference
2. What are AGM Batteries 
3. What are GEL Batteries 

4. Similarities

5. Differences

Overview on the Key Difference

The key difference between AGM and GEL batteries is that AGM batteries allow discharging up to 50%, whereas GEL batteries allow discharging up to 90%, ensuring a long service life.

What are AGM Batteries?

AGM batteries are Absorbed Glass Mat batteries that are designed uniquely to trap the electrolyte between the plates inside the battery. These batteries are also known as SLA batteries, meaning sealed lead-acid batteries or VRLA batteries, meaning valve-regulated lead-acid batteries. We can characterize this type of battery by a limited amount of electrolyte that is absorbed in a plate separator or formed into a gel that proportionates the negative and positive plates so that the recombination of oxygen can be facilitated within the cell.

 

These batteries only hold a small amount of acid, unlike traditional wet batteries. This little amount of lead acid is entirely absorbed by the glass mat. It acts as a major safety feature that prevents the acid from leaking from the battery even if the battery gets broken. Therefore, we can name these batteries non-spillable and maintenance-free batteries. They have a wide range of applications, including use in emergency lights, alarm systems, medical equipment, and UPS.

What are GEL Batteries?

GEL batteries are a type of lead-acid battery that is built with a gel electrolyte. This gel electrolyte is designed to mix with sulfuric acid and fumed silica, which causes a chemical reaction to occur. This chemical reaction causes the gel electrolytes to be immobile. In addition, it is helpful to make the battery free of maintenance and spill-proof. Therefore, we can install the battery in any direction without worrying about acid leaks.

Moreover, GEL batteries have deep cycling capabilities, which makes them an ideal battery option for many applications. These include applications such as solar and wind energy, electric vehicles, wheelchairs, golf carts, cleaning equipment, etc. 

Similarities

The two batteries are classified as Valve Regulated Lead-Acid (VRLA) batteries. The oxygen produced on the positive plates of lead-acid batteries is absorbed by the negative plates. In turn, the negative plates produce water. This helps expel the heat from the chemical reaction produced by the electrolytes. Because of this, the user does not have to water these batteries, making them maintenance-free.

Differences

The fact that AGM offers more than gel batteries is not new. AGM models outsell gel batteries at about 100 to 1. The main reason for this is due to the cost difference. AGM is less expensive than gel batteries.

 

● AGM batteries have a very slow self-discharge rate

AGM batteries also offer a lot of useful qualities that make them the one to pick. AGM batteries are high quality and work at optimal capacity at a large range of temperatures. They work great for all high amp needs and have a very slow self-discharge rate (meaning you can leave one plugged in and you won't waste a lot of energy).

 

● AGM batteries last longer

The thick AGM separator absorbs and holds acid to prevent spilling. And the precision assembly creates a uniform book of plates that are tightly compressed in each cell and held under pressure in the rigid battery case. The result? A battery that resists vibration, recharges faster, cycles more and last longer in demanding applications.

 

● AGM batteries charge easily

AGM batteries charge very easily and hold their charge very well. Gel batteries are very delicate things; one mistake in charging them will ruin the battery completely​, even if it is new. Because they're delicate, and cost more, gel batteries are not a first choice for most applications.