9 Things You need to know for Lead-Acid Battery

Since you’re reading this, you obviously have some questions about lead-acid batteries. For instance, how does a lead-acid battery work? For that matter, what exactly is a lead-acid battery?

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Are these batteries still efficient enough for certain uses or are they obsolete? How do they compare to other batteries?

Fortunately, we have all the answers you’ve been looking for right here in this guide. To start with, we can assure you that these batteries are not obsolete. There are, in fact, many applications in which it’s ideal to use lead-acid batteries.

We’ll explain this in more detail below. We also provide a comprehensive explanation about what a lead-acid battery is and how it works. Read on to learn all there is to know about lead-acid batteries.

What Exactly Is the Lead-Acid Battery?

A lead-acid battery is a rechargeable battery that uses lead and sulphuric acid to function. The lead is submerged into the sulphuric acid to allow a controlled chemical reaction.

This chemical reaction is what causes the battery to produce electricity. Then, this reaction is reversed to recharge the battery.

Believe it or not, this technology is over 100 years old. However, it has been improved upon since its invention in  and it now works more efficiently.

How Does the Lead-Acid Battery Work?

To put it simply, the battery’s electrical charge is generated when the sulphate in the sulphuric acid becomes bonded to the lead. The electrical charge is replenished by reversing this reaction. That is, the sulphate goes back into the sulphuric acid and, thus, the battery is recharged.

Now, obviously, there’s a finite amount of sulphate ions in the acid. And the available surface area of the lead it bonds to is limited, too. So, as the sulphate is depleted, the charge becomes weaker.

For this reason, lead-acid batteries are not ideal for powering devices for a long period of time. Instead, they’re best for applications that need a short, powerful burst of energy.

What Is the Amp Hour Rating?

12V Lead Acid Batteries are commonly used in a variety of applications. This ranges from automotive batteries to home energy storage solutions.

However, when selecting the right battery for any particular purpose, one of the most important considerations is the capacity rating.

This is also known as the amp-hour (AH) or milliampere-hour (mAh) rating and provides an idea of how much power this battery can deliver over a period of one hour without dropping below its minimum voltage level.

For example, a higher AH or mAh rating means that more energy can be drawn from the battery in a given period before it needs to be recharged.

Consumers should make sure they choose a battery with a high enough capacity to suit their needs.

The Self-Discharge of the Lead-Acid Battery

One unfortunate disadvantage of lead-acid batteries is that the chemical reaction described above can never be halted completely. In other words, these batteries will continue to discharge even when they’re not in use.

Normally, this self-discharge happens somewhat slowly, around 1% lost per day. But certain factors will increase this rate. For instance, the warmer the battery is, the faster it self-discharges.

Also, some devices use a little of the battery’s charge even when they’re turned off. The audio settings in your car are a good example of this. Your car radio uses battery power to “remember” these settings.

In any case, you’ll have to make sure you recharge your lead-acid batteries every once in a while or they will die.

Capacity of the Battery

A 12V Lead Acid battery has many uses, both in small and large applications. With this type of battery, it is critical to understand its capacity – which is measured in Amp-hours (Ah) or Milliamp-hours (mAh).

This is the amount of energy output from the battery before requiring a recharge.

This means that when you look at a 12V Lead Acid Battery, the higher the AH rating, the more power it will have. This will last for a longer time before it needs recharging.

Knowing and understanding your battery’s capacity is key to ensuring you get quality performance out of your purchase.

The Death of the Lead-Acid Battery

So, what causes a lead-acid battery to die? Certain factors can damage or change the materials that are needed to cause the necessary chemical reaction. One such factor is allowing the battery to remain in a partially discharged state for too long.

Partial Discharge

As the battery discharges, it lowers the amount of electrolyte solution (the sulphuric acid mixed with water). This leaves the lead plates partially exposed.

If they remain exposed, the sulphate that is already bonded to the lead can harden. Then, it remains on the lead permanently, which decreases the battery’s ability to recharge.

This partial discharge is a common problem with car batteries. You see, the battery recharges when you drive. But if you don’t drive often, or you always make very short trips, your battery might never get fully recharged.

Deep Discharge

Another common cause of battery death is deep discharge. This is when your lead-acid battery is discharged below 50%.

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When this happens, small pieces of the lead plates can actually break off and sink into the electrolyte solution. Then, there is less material available to cause the chemical reaction. If too much is broken off, the reaction won’t happen at all.

This is why your car battery becomes unusable if you accidentally leave the headlights on overnight. Even if you’re able to jump-start the dead battery, the damage has already been done. The battery is permanently ruined and will have to be replaced.

Overcharging

Overcharging happens when you keep charging a battery that’s already full. Doing this can break down the material of the electrolyte. Once this happens, there is no sulphate left to bond with the lead.

This is why you don’t want to keep a lead-acid battery plugged into a charger all the time. It’s better to only plug it in once in a while.

Pros and Cons of the Lead-Acid Batteries

Lead-acid batteries have powerful voltage for their size. Thus, they can power heavy-duty tools and equipment.

They can even power electric vehicles, like golf carts. However, in this case, you’d need to be careful to charge the battery often enough (and without overcharging it). If you don’t, the vehicle will die before reaching its destination, which will also damage the battery.

Additionally, lead-acid batteries are great for starting motor vehicles. They provide an intense jolt of energy to start the vehicle and then they recharge as the vehicle drives.

On the other hand, they are not good for devices you wish to use for long periods of time, like cell-phones. Also, they self-discharge when not in use, which will eventually kill the battery.

In other words, you can’t just leave them sitting around. Thus, they are a bad option for any application that will not be used frequently.

Regular Maintenance Is Essential

12V lead acid batteries are reliable power sources but require careful management to perform at their best. Charging and discharging should be closely monitored.

The batteries should never run out of power completely as this can make them not work as well.

Keep the batteries clean, and don’t forget to replace the electrolyte yearly. With these steps, you will ensure maximum capacity out of your 12V lead acid battery for years to come.

The Best Way to Maintain Lead-Acid Battery

One of the most important factors to consider when buying and using a 12V lead acid battery is its capacity. In general, these batteries have a much longer lifespan than other types.

But must still be regularly maintained in order to truly benefit from their longevity.

While charge levels should be monitored on a regular basis, and plates should also be cleaned with a cleaning agent suggested specifically for lead acid batteries.

One of the most important things a user can do to maintain their battery is to change the electrolyte annually on average.

Doing so will help ensure that your battery lasts as long as possible and continues to provide reliable power for years to come.

What Will You Use Lead-Acid Batteries For?

Article overview

• Battery Basics: Explains differences between AGM (Absorbent Glass Mat) and flooded lead‑acid batteries, focusing on design and how each stores and delivers power.
• Maintenance & Performance: AGM batteries are sealed, spill‑proof, low‑maintenance, and perform better in high‑heat and high‑demand situations compared to standard lead‑acid batteries, which need regular upkeep.
• Cost & Lifespan: AGM batteries cost 40–100% more but can last longer (up to 10 years) and recharge faster, while lead‑acid options are cheaper with a typical 3–5 year lifespan.
• Environmental Impact: Both battery types are recyclable, but AGM’s sealed design offers slightly lower ecological risk and easier handling.
• Ideal Use Cases: AGM batteries are recommended for modern vehicles with high electrical loads, hot climates, or drivers who want low maintenance; lead‑acid works for budget‑focused, standard vehicle needs.

Two options stand out in the world of automotive batteries: absorbed gas mat batteries and lead acid batteries. While both serve the same purpose of storing and delivering electrical energy and share the same chemistry, their construction, performance and applications differ. Understanding the distinctions between these types can help consumers make informed decisions. 

What is a regular lead car battery?

Also called flooded batteries, regular lead acid car batteries are the most common in cars, trucks and vans. Divided into six separate cells with positive and negatively charged plates, a flooded battery contains a liquid electrolyte solution that each plate is submerged in to create a path for electricity to flow through. 

A lead acid battery relies on this solution of liquid electrolyte to operate. Without it, limited chemical reactions hamper the communication between the lead plates. This significantly reduces the battery's capacity and voltage output, making it unable to provide the necessary power to start the car or run the electrical system. Operating a flooded car battery without enough electrolyte can also damage the internal components of the battery and might lead to corrosion. Flooded batteries also need to be stored in well-ventilated areas of the vehicle, since they release gases into the atmosphere. 

What is an AGM car battery? 

Designed to provide more amps even if the car engine is off, absorbed gas mat (AGM) batteries are becoming more common in the industry. Instead of holding freely flowing electrolytes, AGM car batteries have a glass mat separator between the lead plates. Designed to absorb and immobilize electrolytes, the glass mat prevents spillage even if the battery is cracked or damaged. This design also has pressure relief values to regulate internal pressure and to avoid gas buildup, making AGM batteries ideal for use in vehicles with batteries in the trunk or under seats. 

AGM batteries require less maintenance than flooded batteries and are generally considered maintenance-free. Because the electrolyte is enclosed in the glass mat, these batteries can be mounted in various orientations without risking electrolyte leakage.

The differences in power output of AGM vs. lead

A battery’s internal resistance can affect its performance. The internal resistance of an AGM battery can be as low as 2%. In comparison, a flooded battery can have an internal resistance of 10-15%. The lower internal resistance means an increased battery voltage output while helping AGM car batteries recharge faster. This is important in help the battery recover quickly from deep discharges commonly occurring in hot weather conditions or because of the abundant technology in newer cars. 

Speaking of hot weather, regular lead batteries work well in any climate. However, using an AGM battery is best for those living in climates consistently above 80 degrees Fahrenheit. Exposure to high temperatures can cause car batteries to have increased electrolyte evaporation, reducing the battery's performance and lifespan. In addition, heat causes corrosion buildup and sulfation (crystal accumulation) on the battery plates. Since AGM batteries have the plates encased, these effects of heat are minimized.

Which is more expensive, AGM or lead car batteries? 

Initially, an AGM battery will cost more than a regular lead acid battery. The cost can be significant, in fact, as much as 40 to 100% more than the cost of a regular lead battery. 

Flooded batteries can last three to five years with regular maintenance and proper care. This lifespan will vary based on factors such as temperature, battery quality and cycling frequency. If the battery isn't maintained or lives in harsher conditions, that lifespan can drop from one to two years.

Owners can expect an AGM car battery to typically last between three and five years with proper usage. With its sealed design, internal components are protected from contamination and electrolyte loss, which contributes to its longevity. In some cases, higher-quality AGM batteries may last up to 10 years, depending on the application and environmental conditions. Also, AGM batteries are maintenance-free and eliminate the need for regular electrolyte checks and refills that are commonly required for flooded batteries.