AGM Vs Gel: Which Is The Best SLA Battery?

The Valve Regulated Lead-acid batteries include AGM and gel technology. These are also known as SLA. People get confused and consider them to be one and the same for the similar core of attributes.

The striking difference between the two is the electrolyte. The electrolyte in Gel batteries have a look of jelly, but the AGM batteries have electrolytes absorbed in glass mat like separators. The gel batteries can work in warmer temperatures, while AGM batteries work efficiently in cold temperatures.

There are more differences between them. Let’s have a discussion on the comparison and choose the right one according to your need.

What is an AGM battery? 

AGM battery is made by holding the electrolyte in place by a separating membrane. The battery works by the capillary properties of the membrane. These ‘membrane’ batteries are made of fiberglass mat.

By producing a very thin separating membrane, high output power can be created with batteries of relatively small size. 

The AGM batteries are recombinant, and so the Oxygen and Hydrogen recombine inside the battery.

This utilizes the gas phase transfer of oxygen to the negative plates to recombine them back into the water while charging and prevent the loss of water through electrolysis.

The best part is the recombining is typically 99+% efficient, so almost no water is lost.

AGM or dry cell batteries are the newest type and safer than wet cells. It is also a durable choice for moving from one place to place. 

What Is A Gel Battery?

A specific mixture of silicon is added to the battery acid to transform the electrolyte into a gel-like substance in the gel batteries.

By the drilling of channels in the gel, gaseous oxygen goes from the positive terminal to the negative terminal.

It gets hydrogen gas and recombines into the water, releasing energy.

These batteries are quite resistant against excessive deep discharge and retain the operation even at the discharge of the battery to 20% of the nominal capacity.

Actually, Gel Batteries come with great capacity.

How To Recognize AGM and Gel Batteries?

The AGM lead-acid batteries will be labeled as – AGM, or, ‘Absorbed Glass Mat, or dry cell, sealed regulated valve, non-spillable, or valve-regulated on the label.

On the other hand, the gel-filled lead-acid batteries come with a ‘Geld filled’ label on the battery.

AGM batteries are also called ‘starved electrolyte’, or membrane batteries. 

AGM vs Gel Batteries: A Detailed Comparison

The agm vs gel batteries have a clear difference between them. They are different in electrolytes, made for different uses. Let’s have a glance at the key differences between these two types of batteries. 

FeaturesAGM BatteryGel Battery
PowerSuitable for high amp with a very slow self-discharge rateSuitable for lower high amp
ChargingEasyDelicate and needs caution
Lifespan4 to 8 years2 to 5 years
CurrentSuitable for higher currentsWarmer weather
TemperatureColder weatherWarmer weather


Since the thick AGM separator’s precision assembly comes with a tightly compressed book of plates, it resists vibration.

The electrolyte-soaked glass mats in between the lead plates act like a damper.

Additionally, it also recharges faster and cycles more. 

On the other hand, gel batteries also come with great vibration-resistant. However, it is lower than the agm batteries. 


For the large range of temperature, the AGM batteries can work at optimal capacity.

Besides, this type can work great for all high amp with a very slow self-discharge rate. That means you won’t waste much energy while leaving plugged.

These batteries have the power to start a car engine more than 60,000 times which is around 3x more than what traditional batteries can do. 

On the other hand, gel batteries come with a lower power capacity. This battery is suitable for a relatively low burst of amps. 


Agm batteries get charged very easily and hold the charge very well. Most importantly, it lasts longer than other batteries in demanding applications.

Since the charging voltages are the same as for any standard battery, there is no need for any special adjustments or problems with incompatible chargers or charge controls.

And for the extremely low internal resistance, there is almost no heating of the battery even under heavy charge and discharge currents. 

On the contrary, get batteries are delicate. And if you make some mistake in the charging, it will ruin the battery completely.

They must be charged at a slower rate(C/20) to prevent excess gas from damaging the cells.

You can’t use the conventional automotive charger to get the gel batteries fast-charged. 

Battery lifespan 

According to the depth of discharge, temperature, maintenance, and how often and how deep cycled, the lifespan of agm batteries is around 4 to 8 years and gelled deep cycle battery is around 2 to 5 years. 

Actually, the lifespan varies considerably with how it is used, how it is charged and other factors. 


The AGM batteries have no charge or discharge current limits. Most importantly, AGM’s have a very low self-discharge – from 1% to 3% per month.

So, they can sit in storage for much longer periods without charging than standard batteries. Gel batteries are best suited for deep discharge as they are more acid starved.


AGM batteries are less expensive than gel batteries, and that’s why the former outsells the latter at about 100 to 1. 

What Are The Similarities Between Agm And Gel Batteries? 

Since these batteries are SLA batteries, spill-proof and low-maintenance, these are more similarities –

For the design: Both batteries have flat tops except for the positive and negative ends. 

After a hard shake: These batteries won’t wiggle when you keep them still after a hard shake. 

Flexible and non-spillable: These batteries are flexible as you can mount them anywhere. 

Caution: The batteries can get easily damaged if the charging current is too high. You can’t use a regular battery charger on these dry cell batteries. 

Which One Is For You – AGM Or Gel Battery?

It actually depends on the features of the specific battery you want to purchase. 

Quick charging or high discharge can cause severe damage to a gel battery.

But agm batteries come up with a modern idea with the same concept of gel battery – more flexibility and higher performance. 

However, the advantage of gel batteries is that it is quite impossible to spill acid even if they are broken. But they have to be charged at a lower voltage (2/10th’s less) than AGM batteries. 

Tip: For 12-volt Gel or AGM batteries, the average use of seven years is perfectly normal. The battery can still be used if only 50 % of the battery capacity is actually required.

Why should you go for AGM battery?

– Perfect for the operation when a burst of amps is required.

– Comes with a longer lifespan

– Sometimes 5 times faster recharge rate.

– Preferable as a starter battery

– Less expensive

– Have a low internal resistance.

– Good for below 32 degrees.

– Have higher cold cranking amp (CCAs) 

Some Recommended AGM Batteries –

Renogy Deep Cycle AGM Battery

The 100Ah battery comes with Proprietary quinary alloy plates and specially treated plate grids. It reduces the monthly self-discharge rate below 3% at 77℉ (25℃), which is 5 times lower than their flooded counterparts

Weize 12V 100AH Deep Cycle AGM

It is also a heavy-duty battery that comes with the calcium-alloy grid that provides exceptional performance and service life.

Why Should You Go For Gel Battery?

– Suitable for warmer environments.

– Compatible with deep discharge rates.

– You can use this battery in solar energy storage, electric cars, ventilators in health facilities, and so on.

Some Recommended Gel Batteries –

ML35-12 GEL – 12 Volt 35AH Rechargeable Gel

This is a 12 volt 35 Ah maintenance-free battery which can be carried to any place.

Renogy 12V 200AH Rechargeable Deep Cycle Hybrid Gel

This is a 200Ah hybrid gel battery which has corrosion-resistant grids that enable more than 750 discharge cycles at 50% DOD in cyclic applications.


So, which is the ultimate winner between AGM vs Gel battery? 

The AGM and GEL batteries are recombinant, and so both are spill-proof and can be installed in any position. But their electrolytes are discharging level make them appropriate for different tasks.

So, go for one which meets your need. And don’t forget to let us know.

Related Posts:

Leave a Comment

Your email address will not be published. Required fields are marked *