AGM or absorbent glass mat batteries have been popular for more than thirty years now. While initially it was a preferred sealed lead acid battery for use in military aircrafts, UPS and commercial long haul vehicles, AGM batteries have a much more diverse and widespread use. Like all other types of lead acid batteries, there are some AGM batteries pros and cons. Before we figure that out, let us explore how AGM batteries work.
AGM Batteries: Explained
AGM batteries have a fine fiberglass mat that absorbs the sulfuric acid in the battery, hence making the unit spill proof. The battery is relatively lighter and is more reliable. AGM batteries can be shipped without any labeling of hazardous material and hence becomes more convenient to ship. AGM batteries can be blocks or rectangular in shape, you could have cylinders or cylindrical cells as well.
AGM batteries are not very vulnerable to sulfation, an issue with most other batteries. In contrast to the flooded lead acid type batteries, the AGM batteries are safer, more reliable and can provide sufficient power as and when needed. It can meet spike in demands of power in given instants. AGM batteries also withhold charge much longer and don’t have major issues with self discharge. Let us now check the pros and cons of AGM batteries.
List of Pros of AGM Batteries
1. Spill Proof
AGM batteries are spill proof because of the matting technology that encapsulates the acid.
2. High Power Output
AGM batteries have very little resistance inside and thus can provide bursts of power as and when needed. AGM batteries are much more responsive to load than other batteries.
3. Quick Charging
AGM batteries can be charged very quickly. Compared to flooded lead batteries of the same capacity the AGM batteries can charge five times faster with the same power source.
4. Longer Lifespan
AGM batteries last longer than flooded batteries. Not only does it last longer for the same job, it also manages to last longer when not in use. One doesn’t have to keep charging it or worry much about the self discharge as is the case with many other types of batteries.
5. Safe, Reliable & Sturdy
AGM batteries are good at water retention. They can resist vibration which is why they are now being used in racecars and high end motorcycles. The sandwich construction of AGM batteries make sure the components don’t fall apart or become vulnerable to wear and tear when subjected to significant vibrations. AGM batteries can withstand high and low temperatures. They perform well in cold conditions. Even if you don’t attend to topping charge regularly, AGM batteries will hold against sulfation. In many ways, AGM batteries are reliably safe.
List of Cons of AGM Batteries
1. Cost of Manufacturing
AGM batteries have a much higher cost of manufacturing than flooded battery types. However, the cost is cheaper than gel type batteries. While costs of manufacturing AGM batteries have come down since its nascent days in the eighties, yet they remain high which make them a tad unaffordable for many types of utilities.
2. Overcharging Issue
AGM batteries are quite sensitive to overcharging. Gel batteries have significantly higher levels of tolerance compared to AGM batteries.
3. Declining Capacity
While the lifecycle of AGM batteries is reliable and desirable, the capacity actually declines with time, rather gradually. Gel batteries are appreciated for their performance dome. AGM batteries don’t have such a feature.
4. Energy & Environmental Concerns
AGM batteries have low specific energy. The bursts of energy would be useful but low specific energy makes them unusable in many devices. AGM batteries need to be stored in charged condition, which is not as much of a requirement for flooded batteries. AGM batteries have substantially less lead and electrolyte, which makes them less environment friendly than flooded batteries. However, there is no evidence that suggests AGM batteries to be unsafe.
AGM Batteries: The Bottom Line
AGM batteries have desirable low internal resistance, can output high currents, have long service life, there is no maintenance needed, is reliable and lightweight, there is no need for topping charge once in six months, they can sit in storage for a really long time and have a desirably low self discharge. AGM batteries have 80% depth-of-discharge while flooded have 50%. AGM batteries come in the range of 30Ah to 100Ah and are suited for power-hungry functions such as heating of seats in cars, powering steering wheels, windshields and mirrors, marine and robotic applications.
On the flipside, the sensitivity to overcharging is a concern but so is the case with all sealed and gel type batteries as well. AGM batteries don’t have a sturdy threshold for heat and should be kept away from engines or components that get hot. AGM batteries shouldn’t have a core temperature increasing 49°C or 120°F.