Flooded vs. AGM: What is the Best Battery for Your Car or Truck?

Power - by Joe Weber - updated on 8/26/2024

The battery in your car or truck performs many important functions, from providing the energy needed to start your engine, to powering clocks and computer systems when your vehicle is idle. There are many options available, so which is best for your car or truck?

What Type Of Battery Is Used In A Car?

The type of battery under your hood can have a big impact on your car's performance and reliability. Today we'll look at the notable differences between the two most common batteries, flooded and AGM, including the advantages and disadvantages of both.

To learn more about how car batteries are constructed and work, read our blog "How Does a Car Battery Work?"

Flooded Batteries

Flooded lead-acid batteries, commonly referred to as conventional lead-acid, are the most commonly used in cars and trucks.

Flooded 12-volt lead acid batteries are divided into six different cells. In each cell, positive and negatively charged plates are arranged with a plastic separator placed between them. An electrolyte solution is then added which creates a path for electricity to flow.

Flooded batteries are filled with an electrolyte solution that covers the lead plates to complete the chemical process to generate energy. They're cheap and easily accessible, making them the preferred choice for many drivers.

Here are many of the benefits of using flooded lead-acid batteries:

• Cost-Effective: They are generally more affordable than other types of batteries, making them a cost-effective choice for many applications.
• Reliability: Flooded lead-acid batteries have a long history of reliable performance and are well-understood in terms of maintenance and usage.
• Ease of Maintenance: While they do, in some cases, require regular maintenance (such as topping up the electrolyte levels), this also allows for better control over the battery's condition and longevity.
• Widespread Availability: Due to their long-standing use, these batteries are widely available and can be easily replaced or serviced.
• Recyclability: Lead acid batteries have nearly a 100% recycling rate in the United States. This helps reduce environmental impact and conserve resources for future generations.

Special Note

Flooded lead-acid batteries also come in deep-cycle varieties, which are very different from the batteries in your vehicle. Your car or truck uses starting batteries, they are designed to provide short, powerful bursts of power needed to turn over engines; they are not designed for the deep cycle operations required in a boat or to power additional conveniences in an RV.

AGM Batteries

AGM batteries (short for Absorbed Glass Mat) are constructed slightly differently than their flooded counterparts. The plate separator within an AGM battery is made of fiberglass, which absorbs the electrolyte, holding it in place.

This increases their durability and allows you to mount them in many positions (don't turn them upside down though) without fear of spilling, which can happen with flooded batteries. AGM batteries also have a lower internal resistance, giving them a higher voltage output and a dramatically shorter charging time.

AGM batteries have several other advantages over flooded types:

• Maintenance-Free: AGM batteries are completely sealed and don't require periodic topping off with water, making them maintenance-free.
• Longer Lifespan: Due to their design, AGM batteries are less prone to sulfation and other common battery issues.
• Better Performance: They provide better starting power performance, with higher cold cranking amps (CCA) and more consistent power delivery.
• Vibration Resistance: AGM batteries are more resistant to vibrations and bumps, making them ideal for use in vehicles that experience rough driving conditions.
• Deep Cycle Capabilities: They can handle deep discharges better than flooded batteries, making them suitable for vehicles with many electrical demands or equipped with start-stop technology.
• Temperature Performance: AGM batteries can handle the extreme temperature fluctuations that can occur in many regions of the United States better than their flooded counterparts.

Special Note About AGM Batteries

All vehicles can be upgraded to an AGM battery but not all cars can be downgraded to a flooded battery. If your car's original battery was an AGM type, you have to continue using AGM batteries going forward, as your car will not accept a flooded battery.

Vehicles come with AGM batteries for a reason, usually due to high power demands or the vehicle being equipped with start-stop technology. A flooded battery would not have the power necessary to run all of the electronics in the vehicle.

Are GEL Batteries Used In Cars?

Another type of battery you might encounter is a gel battery, which uses silica to turn the electrolyte inside into a gel substance. It is rare to see GEL batteries in cars but they are common in other applications like forklifts, power wheelchairs and other deep-cycling applications.

Which One Is Right For You?

There are quite a few differences between different types of car batteries, so which one do you pick? The answer is simple, it depends. Ok, so it's not that simple. The battery is best for you will depend on how and where you use your vehicle. If you have a lot of electronics in your vehicle or start-stop, you'll probably need an AGM battery. If you drive and store your car in very hot or very cold climates you may also benefit from using an AGM battery.

But, if you need help deciding which battery is the best battery for your car or truck, stop by your nearest Batteries Plus and our knowledgeable staff will walk you through your options so you can make the best decision.

If you're experiencing problems with the battery in your car or truck, we'll even test it for you too, for free. If you do require a new battery, we have flooded and AGM options available for your vehicle from trusted brands like Duracell and X2Power.

Plus, to add to how great Batteries Plus is, we offer installation services for your car or truck battery at any of our 700+ locations nationwide. Purchase your battery and schedule your battery installation online today! (Certain restrictions apply to some makes and models. Fees may vary from location to location or the difficulty of the installation. Please contact your local store for more information. )