VRLA AGM Battery..

Absorbent Glass Mat (AGM)

AGM technology became popular in the early 1980s as a sealed lead acid battery for military aircraft, vehicles and UPS to reduce weight and improve reliability. The acid is absorbed by a very fine fiberglass mat, making the battery spill-proof. This enables shipment without hazardous material restrictions. The plates can be made flat to resemble a standard flooded lead acid pack in a rectangular case; they can also be wound into a cylindrical cell.

AGM has very low internal resistance, is capable to deliver high currents on demand and offers a relatively long service life, even when deep-cycled. AGM is maintenance free, provides good electrical reliability and is lighter than the flooded lead acid type. It stands up well to low temperatures and has a low self-discharge. The leading advantages are a charge that is up to five times faster than the flooded version, and the ability to deep cycle. AGM offers a depth-of-discharge of 80 percent; the flooded, on the other hand, is specified at 50 percent DoD to attain the same cycle life. The negatives are slightly lower specific energy and higher manufacturing costs that the flooded. AGM has a sweet spot in midsize packs from 30 to 100Ah and is less suitable for large UPS system.

Advantages

• Spill-proof through acid encapsulation in matting technology.
• High specific power, low internal resistance, responsive to load.
• Up to 5 times faster charge than with flooded technology.
• Better cycle life than with flooded systems.
• Water retention (oxygen and hydrogen combine to produce water).
• Vibration resistance due to sandwich construction.
• Stands up well to cold temperature.