Valve Regulated Lead Acid Battery
Valve regulated lead acid batteries, also known as SLA or VRLA are a type of lead–acid battery. They operate under the oxygen recombination principle.
SLA/VRLA batteries are maintenance-free and non-spillable. They have a safety vent that releases excess gasses in case of excessive internal pressure build-up.
The electrolyte in SLA/VRLA batteries is immobilized as gel or absorbed into sponge-like glass mats, which eliminates the evaporation and spillage of wet cell lead–acid batteries.
Absorbent Glass Mat (AGM) Separator
AGM batteries have a long lifecycle and do not need to be topped up with water. These batteries also have a low self-discharge and are non-spillable. They are ideal for use in emergency lighting systems, alarm systems, and UPS systems. The demand for AGM separator batteries is anticipated to grow in the near future, driven by stringent government regulations regarding fuel consumption and carbon emission.
AGM, or Absorbed Glass Mat, is a type of SLA/VRLA battery that utilizes a fine fiberglass mat to absorb the sulfuric acid electrolyte. This makes the batteries non-spillable, and it enables them to be shipped without hazardous material restrictions. These batteries are also maintenance free and are position insensitive. However, they should be charged with care to prevent over or under charging which can damage the battery and shorten its lifecycle. They also have a higher depth of discharge than gel batteries, and they are more resilient in cold temperatures. The morphology of the AGM separator plays an important role in determining its performance and battery lifetime. Key morphological attributes include pore volume, acid absorption capability, compression characteristics, and gas recombination efficiency.
Absorptive Glass Mat (AGM) Cells
The absorbent glass mats soaked with electrolyte give AGM batteries a higher depth of discharge than traditional lead-acid batteries and allow them to provide big bursts of power. They also charge quicker than traditional batteries and have a longer life span because of their low internal resistance.
AGM batteries can be mounted in any orientation and resist vibration better than flooded or sealed VRLA batteries. They have a spill-proof secure design, can sit in storage for longer periods of time without needing to be charged and hold their power better than traditional batteries in cold temperatures.
They are a great choice for electric vehicles, home back-up power systems, off-grid valve regulated lead acid battery renewable energy systems like wind and solar power, or even as a replacement battery in motorcycles and ATVs. However, if you need your battery to run at high levels of power for long periods of time, it is best to size them to have a more conservative DOD (depth of discharge) as extreme deep-discharging shaves off capacity and limits lifespan.
Absorbent Glass Mat (AGM) Electrolyte
AGM batteries offer spill-proof secure electrolyte, universal mounting flexibility, good vibration resistance, and a long lifecycle. They are especially suitable for start-stop hybrid vehicles and mild-hybrid cars that require stable power.
The woven fiberglass mats and plates in an AGM battery are tightly packed, making it highly resistant to mechanical shocks and vibrations. This robust construction also allows them to handle higher discharge rates than flooded lead acid batteries.
These factors make AGM batteries very popular for automotive and marine use, providing a reliable source of power for cranking and high-rate discharge applications. They also provide a longer cycle life and lower internal resistance than standard flooded lead acid batteries, making them better for frequent and extended float charge applications.
AGM and gel batteries are often called maintenance free, but they still have pressure valves that open at a certain point during the charging cycle to vent gases. When a battery is charged with too much voltage, the water molecules break apart into gas, causing the safety valve to release, reducing pressure. This prevents the battery from overcharging, a major cause of early failure in all types of batteries.
Absorbent Glass Mat (AGM) Plates
The plates in an AGM battery are made from a fine glass mat that holds the electrolyte. The mat allows the electrolyte to reach the battery’s plates, but doesn’t allow free acid to leak out. This allows the battery to be shipped without any hazardous materials restrictions.
AGM batteries have a lower self-discharge rate and can be charged and recharged many more times than standard flooded lead acid batteries. They can also be mounted in any orientation and are more resistant to shocks and vibration than flooded batteries.
AGM batteries still require regular maintenance, but not nearly as much as a flooded lead acid battery. This includes topping off the electrolyte in a deep cycle battery, and maintaining the proper water levels in an AGM or gel battery. They also storage battery manufacturers benefit from a slower charging rate and higher output than standard lead acid batteries. This enables them to maintain a deep discharge state of charge for months and can be used in colder weather. They also offer a more stable voltage during discharge. This technology is less expensive than lithium iron phosphate (LiFePO4) batteries.
Absorbent Glass Mat (AGM) Battery Technology
AGM batteries are designed to address the key limitations of traditional flooded lead acid batteries. They use a fiberglass mat that is saturated with electrolyte to 95% and placed between the plates. This design allows the battery to be able to handle high electrical demand applications, offer low internal resistance and provide better discharging and recharging efficiency. Additionally, AGM battery construction makes these batteries immune to vibration.
Unlike the older flooded batteries that need to be replenished with water, the acid in an AGM battery stays in the fiberglass mat and never leaks out. This means the battery can be used in any position and is exempt from hazardous materials shipping regulations.
AGM batteries are also less likely to sulfate due to their ability to retain charge longer and have lower self-discharge rates than a flooded battery. This is why they are a great choice for high demand applications and seasonally used vehicles.