VRLA stands forvalve-regulated lead-acid battery, a type of sealed, maintenance-free lead-acid battery that is spill-proof and can be mounted in various orientations. These batteries use a pressure relief valve that allows gas to escape only under abnormal conditions, preventing the need for regular watering like traditional flooded lead-acid batteries. They are commonly available in two main types: Absorbed Glass Mat (AGM) and Gel.

• Maintenance-free: They do not require the addition of water.
• Sealed and spill-proof: They can be mounted in various positions, including horizontally, without leaking electrolyte.
• Valve-regulated: A safety valve releases excess internal pressure, a feature that allows the battery to be sealed and prevents electrolyte loss during normal operation.
• Internal gas recombination: They facilitate a process where oxygen produced at the positive plate migrates to the negative plate and is recombined to reform water, which is then absorbed back into the electrolyte.
• Types: VRLA batteries are classified into two types based on how the electrolyte is handled:
  • Absorbed Glass Mat (AGM): The electrolyte is absorbed and held within a separator made of fine glass fibers.
  • Gel: The electrolyte is a thick gel.

• Uninterruptible Power Supplies (UPS)
• Telecommunications
• Security and control systems
• Electric wheelchairs
• Automotive applications in some modern vehicles