What is an SLA Battery? (Learn the Basics)

As someone who has worked with batteries for years, I can tell you that an SLA battery is a type of lead-acid battery with a sealed case. This means you don’t have to worry about adding water to the electrolyte solution or dealing with corrosive electrolytes.

SLA batteries, sealed lead-acid batteries, offer maintenance-free and reliable power. Options like AGM and Gel Cell are ideal for backup power systems, medical equipment, and electric vehicles.

I will dive deeper and cover every facet of these great batteries below.


An SLA or Sealed Lead-Acid battery is a rechargeable battery commonly used in vehicles, uninterruptible power supplies, and other applications. It is a subset of the lead-acid battery family, including flooded lead-acid batteries.

One of the main advantages of an SLA battery is that it is maintenance-free. You don’t have to worry about regularly adding water to the electrolyte solution, which makes it a great choice for people who don’t want to deal with the hassle of maintaining their battery.


An SLA battery comprises several components, including lead plates, an electrolyte solution, and a sealed case. The lead plates are immersed in the sulfuric acid and water electrolyte solution.

The sealed case is made of a durable plastic material designed to withstand everyday use. It is also designed to prevent the electrolyte solution from leaking from the battery.

Overall, an SLA battery is a reliable and cost-effective choice for people who need a maintenance-free and easy-to-use battery.

Haze SLA Battery

Types of SLA Batteries

There are two main types: Absorbent Glass Mat (AGM) and Gel Cell batteries. Both types of batteries are used in the deep cycle and SLI (Starting, Lighting, Ignition) applications.

Absorbent Glass Mat (AGM) Batteries

AGM batteries are popular SLA battery that uses a fiberglass mat to hold the electrolyte solution in place. This design makes AGM batteries spill-proof and maintenance-free, as the electrolyte solution cannot leak out of the battery. AGM batteries are also known for their high discharge rates, making them a great choice for high-performance applications.

AGM batteries are commonly used in various applications, including backup power systems, electric vehicles, and marine instances. They are also used in many consumer electronics devices, such as portable power banks and uninterruptible power supplies (UPS).

Gel Cell Batteries

Gel Cell batteries are another type of SLA battery that uses a gel-like electrolyte solution instead of a liquid electrolyte solution. This design makes Gel Cell batteries even more spill-proof than AGM batteries, as the gel electrolyte cannot leak out of the battery.

Gel Cell batteries are commonly used in deep cycle applications, such as solar power systems and electric wheelchairs. They are also used in many marine applications, as they resist vibration and shock.

Advantages of SLA Batteries

When it comes to batteries, SLA batteries are the way to go. As someone who has worked with batteries for years, I can tell you that SLA batteries offer several advantages.


One of the biggest advantages of SLA batteries is that they are maintenance-free. Unlike other types of batteries that require regular topping up of electrolyte solutions, SLA batteries are completely sealed, so there’s no need to worry about electrolyte spillage. This makes them the perfect choice for things where maintenance is difficult or impossible, such as in remote locations or on vehicles.


Another advantage of SLA batteries is their longevity. These batteries have a long lifespan and don’t lose power over time like other battery types. This means you can rely on them to provide consistent power for years. SLA batteries can last up to five years with proper care and maintenance.

In addition to their longevity, SLA batteries also offer improved safety over other battery types. Because they are sealed, there’s no risk of acid leakage or corrosion, which can be a major safety hazard. This makes them ideal for use in areas where safety is a concern, such as in medical equipment or vehicles.

From their maintenance-free design to their long lifespan and improved safety, these batteries are a reliable and efficient choice for anyone needing consistent power.

charging a hybrid electric car

SLA vs. Gel Cell

SLA Battery TypeAGM (Absorbent Glass Mat)Gel Cell
Electrolyte TypeAbsorbent Glass MatGel
Spill-Proof DesignYes, sealed and maintenance-freeYes, sealed and maintenance-free
Typical ApplicationsBackup power systems, electric vehicles, marine applications, consumer electronicsDeep cycle applications, solar power systems, electric wheelchairs, marine
Discharge RatesHigh discharge rates, suitable for high-performance applicationsModerate discharge rates, suited for deep cycle applications
Vibration and Shock ResistanceGood resistance to vibration and shockExcellent resistance to vibration and shock

Backup Power Systems

One of the most common uses for SLA batteries is in backup power systems. These systems are designed to provide power during a power outage or other emergency.

SLA batteries are ideal for backup power systems because they are reliable, long-lasting, and require little maintenance.

In backup power systems, SLA batteries are typically used in conjunction with an inverter, which converts the DC power from the battery into AC power that can be used to power household appliances and other devices.

Depending on the size of the system and the power requirements, multiple SLA batteries may be used in parallel to provide additional capacity.

Medical Equipment

Another common application for SLA batteries is in medical equipment. SLA batteries are often used to power portable medical devices such as oxygen concentrators, infusion pumps, and patient monitors.

These devices must be reliable and long-lasting, and SLA batteries are well-suited for this purpose.

In addition to portable medical devices, SLA batteries are used in semi-portable medical equipment such as hospital beds and patient lifts. These devices require a reliable power source that can be easily moved from room to room, and SLA batteries fit the bill perfectly.

Electric Vehicles

Finally, SLA batteries are also used in electric vehicles such as electric bikes, scooters, and golf carts. While lithium-ion batteries are becoming more popular in electric vehicles, SLA batteries still have a place in certain applications.

One advantage of SLA batteries in electric vehicles is their low cost. While lithium-ion batteries are more energy-dense and have a longer lifespan, they are also much more expensive. SLA batteries can be a good choice for applications where cost is a primary concern.

Another advantage of SLA batteries is their safety. While lithium-ion batteries have a higher risk of catching fire or exploding if damaged or overcharged, SLA batteries are much less likely to experience these problems.

Overall, SLA batteries are a versatile and reliable choice for various applications. Whether you need backup power for your home, a reliable power source for your medical equipment, or a cost-effective battery for your electric vehicle, an SLA battery may be just what you’re looking for.


  1. Battery University. https://batteryuniversity.com/
  2. Energy Storage Association (ESA). https://energystorage.org/
  3. Battery Council International (BCI). https://batterycouncil.org/

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About Alex Robertson

c3c9d43f1f0d14c4b73cb686f2c81c4e?s=90&d=mm&r=gCertifications: B.M.E.
Education: University Of Denver - Mechanical Engineering
Lives In: Denver Colorado

Hi, I’m Alex! I’m a co-founder, content strategist, and writer and a close friend of our co-owner, Sam Orlovsky. I received my Bachelor of Mechanical Engineering (B.M.E.) degree from Denver, where we studied together. My passion for technical and creative writing has led me to help Sam with this project.

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