Valve Regulated Lead Acid (VRLA) Battery: Basics Explained

Valve Regulated Lead Acid (VRLA) Battery: Basics Explained

We will explain the fundamentals of a valve-regulated lead acid (VRLA) battery in this blog post.

A VRLA battery is one of the most widely used varieties of lead acid batteries, which are available in a variety of sizes and shapes. The Valve Regulated Lead Acid (VRLA) Among rechargeable batteries, the battery is one. Additionally, they are frequently referred to as sealed batteries or maintenance-free batteries.

Learn more about the Valve Regulated Lead Acid (VRLA) battery by reading this blog.

What is a VRLA Battery?

In order to recombine hydrogen and oxygen, a lead-acid battery known as a valve-regulated lead acid (VRLA) battery had its electrolyte immobilized. Its name comes from the fact that it is made of a sealed construction with pressure-release valves to stop gases from escaping.

The gases produced cannot freely form bubbles and rise to the surface of the electrolyte because the electrolyte has either been absorbed into a finely textured glass mat or is no longer a fluid after being combined with silica powder to create a gel. Instead, the pressure gradient created when on charge traps them in the immobilized matrix and forces them to move to the opposing poles. In a free liquid, this would be impossible.

What Are the Advantages of VRLA Batteries?

VRLA batteries are superior to flooded batteries in a number of ways in addition to the benefits already mentioned.

Valve Regulated Lead Acid (VRLA) Battery: Basics Explained
  • Higher voltage output – VRLAs provide more electrical energy than flooded batteries
  • Faster recharge rates – VRLAs can recharge up to 5X faster than flooded batteries
  • Longer lifespans – VRLAs can last 2-3X as long as flooded batteries
  • Slower discharge rates – VRLAs lose their charge much slower in storage
  • Minimal gassing – VRLAs can be used without the need for special ventilation
  • Temperature resistant – VRLAs do a better job of standing up to extreme heat and cold
  • Vibration resistant – VRLAs are more resistant to vibration, making them great for boats & watercraft

Types of VRLA Batteries

There are two types of VRLA Batteries: the Gel Cell and the Absorbed Glass Mat (AGM). And there are other types of lead acid batteries.

Gel Cell Battery

The electrolyte of a gel cell battery, as its name implies, is an immobile jelly-like electrolyte made of sulfuric acid and fumed (pyrogenic) silica, which serves as a thickener. Due to its immobile gel-like electrolyte, the Gel Cell can be mounted in any orientation, is more resistant to extreme temperature changes, and is vibration- and shock-resistant.

Gel Cell Batteries are primarily used in generators, some recreational vehicles, electric wheelchairs, and other devices. Check out Gel Battery Vs Lead Acid Battery: Which is Better?

Absorbed Glass Mat Battery (AGM)

In this kind of battery, the plates are separated by incredibly thin fiberglass mats, which absorb and immobilize the acid. This construction makes the acid readily available to the plates and allows a quick reaction between the acid and plate material. Because the plates in an AGM Battery can be of any shape, their design is very adaptable.

AGM Batteries have the advantage of having a very low internal electrical resistance and faster acid movement between the fiber and the plates than other sealed batteries, which enables AGM Batteries to give and take higher rates of amperage during charging and discharging cycles. See Are AGM Batteries Better Than Lead-acid?

Valve Regulated Lead Acid (VRLA) Battery: Basics Explained

Motorcycles and ATVs are the ideal vehicles for AGM Batteries. Deep-cycle AGMs are also frequently used in large-scale amateur robotics competitions like the FIRST and IGVC as well as off-grid solar and wind power installations as an energy storage bank. Learn what is Deep Cycle Lead Acid Battery.

What Are VRLA Batteries Used For?

AGM batteries work best in high current, high power applications like starting batteries for cars and other vehicles. The fact that an AGM battery can serve as a dual-purpose battery, offering both the strong starting power required to start an engine and the cycling capacity to run additional accessories, contributes to their popularity among boat and RV owners as well.

Gel batteries can discharge much deeper than AGM batteries can. Due to this, they are perfect for cycling activities that involve frequent, heavy use. Marine trolling motors, wheelchairs, and mobility scooters, marine & RV house power, UPS, and other backup applications are a few examples of common uses for gel batteries.

One thing to keep in mind is that gel batteries don’t perform well in cold temperatures since their power declines much faster than an AGM once the temperature drops below 32℉.

Further Reading:

Are There Different Types of VRLA Batteries?

Yes, there are three main types of VRLA batteries, a sealed valve-regulated wet cell, AGM, and gel. Gel cells create a thick gel by mixing silica dust with the electrolyte. These can sometimes be referred to as silicone batteries.

Batteries called AGMs, or absorbed glass mats, have an electrolyte-containing fiberglass mesh sandwiched in between the battery plates.

How Long Do VRLA Batteries Last?

Valve Regulated Lead Acid (VRLA) Battery: Basics Explained

As with all lead acid batteries, the maximum life of VRLA batteries depends on how well they are taken care of. Design lives for these batteries typically range from 3 to 10 years. Over-discharge is the single factor that most frequently destroys VRLA batteries. Any type of VLRA battery that is left in a persistently over-discharged state will begin to hydrate.

When a discharged cell’s water contains the lead and lead compounds from the plates, they dissolve and produce lead hydrate, which is then deposited on the separators. Internal short circuits between the positive and negative plates happen frequently when the cell is recharged. The cell is irreparably damaged once signs of hydration are present.

The containers are opaque, so you can’t tell if hydration has taken place. Hydration can happen even after just one significant over-discharge event. Use a low voltage alert that provides visual and audible alerts when a VRLA battery is about to be critically over-discharged to ensure that you get the most cycle out of it and prevent over-discharge events.

Conclusion: Valve Regulated Lead Acid Battery

The term “VRLA” refers to a particular kind of lead acid battery that was first created in the middle of the 1960s. These handy power sources have a significant impact on a wide range of applications, from industrial to recreational.

One of the most dependable and economical forms of energy storage currently on the market, provided they are properly maintained and protected from over-discharge.


Is Valve-Regulated Lead Acid Battery Good?

There is no periodic water refilling needed for VRLA batteries, and they are maintenance-free. reduces the need for ventilation. The capacity range of VRLA batteries is high (12000 Ah) VRLA batteries will have a longer life.

What Are the Disadvantages of VRLA Battery?

The VRLA battery has an additional problem in that, as it dries out and loses water due to elevated operating temperature and high float charge voltage (overcharging) it loses the energy storage required for a full-capacity battery.

Can I Charge a VRLA Battery?

One of the most effective methods for charging VRLA batteries is the so-called “IUI algorithm.” This is merely a current-limited, CV charge with a CC finishing step at a low current level.

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