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AGM stands for absorbent glass mat batteries and has been the top choice for the past couple of decades. These batteries were designed to be better alternatives to Ni-Cad batteries. Their first use was within the military in the 1980s for vehicles that needed backup power like long-distance trucks and aircraft.
These days though, they have made their way over from the military into our garages. These batteries are no different in the way they are used than lead batteries. The big difference comes with all the benefits these batteries offer over standard lead batteries.
So, I decided to go through the top Pros & Cons of AGM Batteries, but first, let’s talk about the specifics of AGM batteries…
How Do AGM Batteries Work?
These days you can find 12-volt AGM car batteries being used as alternatives to flooded lead-acid batteries.
The AGM batteries contain positive and negative charged lead and oxide plates, which release electrons when the reaction takes place with the sulfuric acid and water inside the battery.
AGM batteries are able to soak up and release the mixture with miniature glass fibers. The liquid is equally distributed while making contact with the lead plates. These electrons flow in series through six cells—each cell running 2V, equaling 12V altogether.
Pros of AGM Batteries
The biggest pro is the construction itself. The electrolytes are held next to the plates in the fiberglass, evenly distributing the mixture over the plates.
Here are some more pros of AGM batteries:
- No spillage.
- Because the acid does not flow freely inside the battery, the fiberglass keeps the liquids from spilling out, even if the battery is broken. Not only does this make it safe to handle, but it protects the rest of the vehicle from the hazardous acid that might cause damage.
- Vibration resistant.
- These batteries were made with military use in mind at first. This is why they were built to be stable and keep the acid from shaking around, thus making them vibration-proof. This is great if you want a stable, reliable battery for heavy off-roading.
- Shock resistance.
- Just like the vibration resistance, they have been built to be able to take a knock.
- Easy installation.
- These batteries have no specific orientation for installation. Mainly due to the design that has no free-flowing liquid. If you need to rotate a battery to make it fit, these batteries are the best option.
- Little to no gas emissions.
- If you need to place a battery in a less than optimally ventilated area, then AGM batteries are the best. They produce very little to no gas.
- Low self-discharge rate, which means that they can be stored for much longer without charging.
- Minimal maintenance.
- There is a reason they are used by the military as well as in other vehicles like wheelchairs, golf carts, and scooters. This is because they are virtually maintenance-free batteries, and the orientation does not matter, which makes them fit better in small areas.
Cons of AGM Batteries
High Manufacturing Cost
With excellent performance and ease of use comes a higher cost price, and here we have a prime example. AGM batteries are more expensive to make than standard lead batteries, but they are at least cheaper than gel-type batteries.
AGM batteries generally have high power outputs, but they, unfortunately, have low specific energy. Specific energy refers to the battery capacity in accordance with its size. Certain devices require batteries to run for extended periods of time under high specific loads and are not suited for AGM batteries.
Reduced Capacity Over Time
AGM’s batteries are able to keep their charges longer than other batteries, which is why they are used in new cars that use much more electronics. However, they slowly reduce their charging capacity over time. Sure, they last longer than standard lead batteries, but gel-type batteries now offer the best performance.
They Are Sensitive To Overcharging
AGM batteries are fickle when it comes to charging. AGM batteries should be charged slowly at low voltages. If you use too much, you might shorten the battery’s lifespan or, worse, break it.
Looking for Some Great Products To Charge Your Batteries?
And don’t forget, you can also reduce battery charging time and frequency simply by having the ideal battery for your vehicle and local climate.
So, take a look at our reviews of the Best Car Battery, the Best Car Battery for Cold Weather, the Best Battery for Diesel Trucks, the Best Batteries for Harley Davidson, the Best ATV Batteries, and our Best RV Battery Reviews!
OK, back to the good and bad of AGM batteries…
You’ll see there’s a remarkably long list of pros when it comes to AGM batteries over standard batteries. However, depending on your use, there can be cons too. Although they are virtually maintenance-free and much safer to operate, they are sensitive to overcharging.
Make sure to maintain and charge your AGM battery the right way, and you’ll be able to take advantage of all its pros.