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Synopsis is below. Want to know more? …check out this link (a subscription to Popular Mechanics / Pop Mech Pro is needed to view the link’s information):
https://www.popularmechanics.com/technology/a62953680/agm-car-battery-explainer/
source: Pop Mech
date: 1/5/2025
Automotive technology has advanced at ludicrous speed, yet modern automobiles still use battery technology that originated in the early 1900s. We should clarify we’re not referring to the battery packs in electric vehicles but the 12-volt battery under the hood of your gas-powered car. Nearly every vehicle you see on the road today uses a lead-acid battery to start the car and run basic electronics when the engine is off. So there has to be a better way, right?
Not exactly. The motorcycle industry is an interesting barometer as it’s enjoyed great success with lithium-ion batteries. Not only are these batteries much lighter than their lead-acid counterparts, but they also offer considerably more cranking power. So it sounds like everyone in the automotive industry would bite your arm off for one. Right? Not so, as these newer batteries experience a considerable performance drop in cold conditions and cost more than the “legacy” alternative.
The best solution in the interim is what’s called an Absorbed-Glass Mat Battery. It enjoys the reliability of a lead-acid battery while presenting impressive performance at a reasonable price.
How Do They Work?
Before we get any further, it would be slightly disingenuous to say lead-acid batteries haven’t changed at all during their life span. That simply isn’t true. The lead-acid chemistry is really all that’s remained from day one. Nearly everything else has changed with Absorbed Glass Mat (AGM) batteries taking the industry by storm. For a crash course on how car batteries work, check out this Youtube video.
Invented in 1859, lead-acid batteries are brilliantly simple and capable. Just as the name implies, they use lead plates submerged into diluted sulphuric acid to sustain a controlled chemical reaction, giving the negative terminal a negative charge and vice versa for the positive terminal. When not in use, the electrons on the negative terminal inherently want to flow back to the positive terminal. They can’t move through the sulfuric acid solution, but can move through a completed circuit that allows them to flow where they want to go—when positive and negative are connected to a device that needs power.
Along with adding a plastic case for protection (and battery acid containment) these batteries have experienced substantial improvements under the hood—no pun intended.
All car batteries use lead-acid chemistry, but there are two different schools of thought. The legacy batteries that we were talking about above are called wet-cell batteries. And they’ve worked just fine for decades. However, newer vehicles with complex electrical systems and tech require much higher electrical demands making Absorbed Glass Mat (AGM) batteries almost a necessity to keep them running properly.
Wet Cell Batteries
As mentioned above, conventional “wet cell” batteries use lead plates submerged into an electrolyte solution (battery acid) to sustain a controlled chemical reaction. Each battery has six cells, charged up to 2.1 volts each. While these have worked just fine for decades, Absorbed Glass Mat (AGM) technology is a much newer variation on the lead-acid theme.
AGM Batteries
Absorbed Glass Mat (AGM) batteries were originally developed in the 1960s to meet the high-performance demands of military aircraft. The move to replace the outdated Ni-Cad batteries was motivated by the need for superior performance, safety, and reliability that these military aircraft demanded—a list including fighter jets.
AGM batteries still function using the same principles as lead acid batteries. They use ultra-thin fiberglass mats to absorb battery acid instead of submerged lead plates—making them spill proof. However, the real genius with these thinner mats is they allow more battery acid to make contact with the lead plates. Thinner plates mean manufacturers can pack more of them in the same given space, making these batteries considerably more energy-dense than their wet-cell counterparts.
This technology showed up in the automotive world in much the same way it did with military aircraft thanks to the increased electrical demands of newer vehicles. In fact, most new vehicles actually need AGM batteries for standard equipment like stop-start, where the engine turns off when you come to a stop. That combined with the greater number of screens and onboard systems makes these more advanced batteries a necessity.
Lithium-Ion vs Lead Acid
Lithium-ion has often been included in the automotive battery conversation. However these batteries have never really come to fruition. The reason? They’re incredibly expensive, and not much better than the AGM batteries that we talked about above.
Interstate Batteries’ premium AGM option can supply 950 cranking amps, weighs 45 pounds, and costs less than $300. A comparably-sized Antigravity battery can supply 1500 cranking amps, weighs 16.5 pounds, and costs just under $1000.
https://www.popularmechanics.com/technology/a62953680/agm-car-battery-explainer/
source: Pop Mech
date: 1/5/2025
Automotive technology has advanced at ludicrous speed, yet modern automobiles still use battery technology that originated in the early 1900s. We should clarify we’re not referring to the battery packs in electric vehicles but the 12-volt battery under the hood of your gas-powered car. Nearly every vehicle you see on the road today uses a lead-acid battery to start the car and run basic electronics when the engine is off. So there has to be a better way, right?
Not exactly. The motorcycle industry is an interesting barometer as it’s enjoyed great success with lithium-ion batteries. Not only are these batteries much lighter than their lead-acid counterparts, but they also offer considerably more cranking power. So it sounds like everyone in the automotive industry would bite your arm off for one. Right? Not so, as these newer batteries experience a considerable performance drop in cold conditions and cost more than the “legacy” alternative.
The best solution in the interim is what’s called an Absorbed-Glass Mat Battery. It enjoys the reliability of a lead-acid battery while presenting impressive performance at a reasonable price.
How Do They Work?
Before we get any further, it would be slightly disingenuous to say lead-acid batteries haven’t changed at all during their life span. That simply isn’t true. The lead-acid chemistry is really all that’s remained from day one. Nearly everything else has changed with Absorbed Glass Mat (AGM) batteries taking the industry by storm. For a crash course on how car batteries work, check out this Youtube video.
Invented in 1859, lead-acid batteries are brilliantly simple and capable. Just as the name implies, they use lead plates submerged into diluted sulphuric acid to sustain a controlled chemical reaction, giving the negative terminal a negative charge and vice versa for the positive terminal. When not in use, the electrons on the negative terminal inherently want to flow back to the positive terminal. They can’t move through the sulfuric acid solution, but can move through a completed circuit that allows them to flow where they want to go—when positive and negative are connected to a device that needs power.
Along with adding a plastic case for protection (and battery acid containment) these batteries have experienced substantial improvements under the hood—no pun intended.
All car batteries use lead-acid chemistry, but there are two different schools of thought. The legacy batteries that we were talking about above are called wet-cell batteries. And they’ve worked just fine for decades. However, newer vehicles with complex electrical systems and tech require much higher electrical demands making Absorbed Glass Mat (AGM) batteries almost a necessity to keep them running properly.
Wet Cell Batteries
As mentioned above, conventional “wet cell” batteries use lead plates submerged into an electrolyte solution (battery acid) to sustain a controlled chemical reaction. Each battery has six cells, charged up to 2.1 volts each. While these have worked just fine for decades, Absorbed Glass Mat (AGM) technology is a much newer variation on the lead-acid theme.
AGM Batteries
Absorbed Glass Mat (AGM) batteries were originally developed in the 1960s to meet the high-performance demands of military aircraft. The move to replace the outdated Ni-Cad batteries was motivated by the need for superior performance, safety, and reliability that these military aircraft demanded—a list including fighter jets.
AGM batteries still function using the same principles as lead acid batteries. They use ultra-thin fiberglass mats to absorb battery acid instead of submerged lead plates—making them spill proof. However, the real genius with these thinner mats is they allow more battery acid to make contact with the lead plates. Thinner plates mean manufacturers can pack more of them in the same given space, making these batteries considerably more energy-dense than their wet-cell counterparts.
This technology showed up in the automotive world in much the same way it did with military aircraft thanks to the increased electrical demands of newer vehicles. In fact, most new vehicles actually need AGM batteries for standard equipment like stop-start, where the engine turns off when you come to a stop. That combined with the greater number of screens and onboard systems makes these more advanced batteries a necessity.
Lithium-Ion vs Lead Acid
Lithium-ion has often been included in the automotive battery conversation. However these batteries have never really come to fruition. The reason? They’re incredibly expensive, and not much better than the AGM batteries that we talked about above.
Interstate Batteries’ premium AGM option can supply 950 cranking amps, weighs 45 pounds, and costs less than $300. A comparably-sized Antigravity battery can supply 1500 cranking amps, weighs 16.5 pounds, and costs just under $1000.
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