What is a AGM battery?
The newer type of sealed non-spillable maintenance free valve regulated battery uses "Absorbed Glass Mats", or AGM separators between the plates. This is a very fine fiber Boron-Silicate glass mat. These type of batteries have all the advantages of gelled, but can take much more abuse. These are also called "starved electrolyte. Just like the Gel batteries, the AGM Battery will not leak acid if broken.