Sealed Lead Acid & Gel

SLA Batteries (Sealed Lead Acid) are a broad category of lead-acid batteries that are sealed and require no maintenance (like adding water). They are non-spillable and typically have a valve to release excess pressure. In fact, the term VRLA (Valve Regulated Lead Acid) is often used interchangeably with SLA and AGM, as it refers to the pressure relief valve found in SLA batteries. 

AGM (Absorbed Glass Mat) batteries are a type of SLA battery. AGM batteries utilize a fiberglass mat to absorb the liquid electrolyte, offering advantages like better vibration resistance and potentially longer lifespan in certain applications. All AGM batteries are SLA batteries, but not all SLA batteries are AGM.

Interesting Fact: Smaller AGM batteries used for non-vehicle and standby applications are frequently referred to as "SLA", while larger AGM batteries used in vehicles such as cars and motorcycles are called "AGM", even though they are all technically both.

Gel batteries, like AGM, are a type of SLA battery. Gel batteries use an electrolyte that looks very much like a silicon gel. The gel physically adds internal structure that keeps the plates and their active material in place. The gelled electrolyte and the plates act as a solid component and are much less prone to vibration and shock damage than flooded or AGM batteries. For this reason, Gel batteries are popular in extreme applications such as powersports - ATVs, PWCs, and other off-road vehicles. Gel batteries are more expensive than AGM and other lead-acid batteries.