Batteries are used to store your energy in off-grid and hybrid applications. AGM batteries are made from Absorbent Glass Matt (similar looking to a sponge) and they are completely sealed. AGM batteries have no maintenance and do not off-gas and therefore do not require venting. FLA Batteries require regular maintenance to ensure their longevity, and must be vented to the outside air. Flooded lead acid (FLA) batteries are commonly found in automobiles, forklifts and pallet trucks.