An AGM battery, or Absorbed Glass Mat battery, is an advanced type of lead- acid battery that uses a special glass mat separator to hold the electrolyte (battery acid) in place instead of letting it flow freely inside the battery. This design makes the battery spill-proof and vibration-resistant. The glass mat absorbs and keeps the electrolyte saturated, allowing efficient ion flow between the battery plates during charging and discharging. AGM batteries are maintenance-free since they do not require watering, and they produce minimal gas, enabling safer and more flexible installations, including positions on their sides without leakage. They also have lower internal resistance than traditional flooded lead-acid batteries, which results in faster charging and discharging, high power output, and the ability to handle deep discharge cycles better. These batteries are widely used in modern vehicles, including cars with start-stop engines, motorhomes, boats, off-grid renewable energy systems, and backup power supplies. They provide longer service life, more engine starts (over 60,000 in some cases), and better performance under high electrical demand than standard batteries. In summary, an AGM battery is a sealed, maintenance-free lead-acid battery featuring a glass mat to absorb the electrolyte, offering improved safety, reliability, and efficiency in various applications.