What is the Main Disadvantage of an AGM Battery?
The main disadvantage of an AGM battery is the up-front cost, when compared to a traditional flooded lead-acid battery. That's it. There is no second place or runner-up position, when someone asks for the (singular) main disadvantage is for an AGM battery.
AGM batteries tend to be heavier than identical group sizes in flooded lead-acid batteries, but if someone is really concerned about the weight of their battery, like a race car driver, they'll also be concerned about the risk of acid spilling out of a flooded battery. In every other application, more weight in a battery generally equals more power and that's a good thing, especially in modern vehicles with high electrical demands.
AGM batteries tend to cost more than flooded lead-acid batteries up front, but they can last far longer than a flooded lead-acid battery on the back end. OPTIMA batteries can last up to three times as long as a flooded lead-acid battery, so until they cost more than three times as much as a flooded lead-acid battery, their main disadvantage will continue to become an advantage as you move through the ownership life cycle.
AGM batteries are better-suited to handle extreme temperatures, both hot and cold, than flooded lead-acid batteries, they are more tolerant of deep-discharge cycles (discharge them more deeply & more often) than flooded lead-acid batteries and they are far more resistant to damage from vibration than flooded lead-acid batteries (up to 15x for OPTIMA).
Anyone who tries to tell you lead-acid batteries are better than AGM batteries in any regard simply does not understand basic battery technology. AGM batteries ARE lead-acid batteries. The same goes for anyone who confuses AGM batteries with gel batteries. Those are two very different technologies and in nearly every consumer application we see, the lead-acid batteries being used are either flooded or AGM and not gel.
We've been roaming car shows for years and often hear people mistakenly refer to an AGM battery as a "gel" battery, but the next time we actually see a gel battery in a car at a car show will be the first. If you're ready to make a battery purchase, please check out our offerings and know that we offer free shipping, factory-direct to your doorstep, anywhere in the continental United States.