What are the differences between AGM sealed lead batteries and Gel sealed lead batteries?

Both kinds of batteries are sealed, valve regulated types allowing them to be used in any position. The difference lies in the way the electrolyte is immobilized. In case of an absorbed electrolyte type (AGM), the newer of the two technologies, the electrolyte is absorbed by the glass fiber separator who acts like a sponge. In a gel-type battery the liquid electrolyte turns into a gel right after the battery is filled. Gel batteries use a different type of separators which are not absorbent. The internal design is otherwise similar. Advantages of AGM batteries when compared to gel type batteries; AGM batteries have a higher AH capacity in the same size case: PS-121000 is a 100AH battery whereas, for example, a gel type battery in the same size case would only be rated 84 AH; AGM batteries are generally about 20% less expensive than comparable gel batteries-AGM batteries have better high-rate discharge characteristics desirable in UPS – telecom applications • AGM batteries are much more readily available; 85 – 90% of all VRLA batteries sold are of the AGM type.