Blog Car Care Advice AGM vs Flooded Battery: Which Is Better for Your Car?
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AGM vs Flooded Battery: Which Is Better for Your Car?

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Confused between installing a new AGM or a flooded car battery? 
Although they rely on the same lead acid technology, their designs differ significantly, impacting everything from power delivery to maintenance needs.

So, how do you decide which is best for you? 
We’ll break down the key differences between AGM vs flooded battery to find which reigns supreme for your needs. 

Let’s go!

This Article Contains: 

AGM vs Flooded Battery: 6 Key Differences

Here are some main distinctions to consider between flooded lead acid (FLA) and AGM batteries:

1. Performance 

Battery performance matters greatly since it affects how reliably your car starts and runs. 

A. AGM Battery 

Sealed lead-acid (SLA) batteries, like absorbent glass mats (AGM), have a low self-discharge rate of 4% per month. In comparison, a flooded lead-acid battery can have self-discharge rates of up to 8% per month.

Moreover, AGMs have a high power output required for luxury and performance vehicles. They also offer superior performance in extreme temperatures. 

B. Flooded Battery

Standard flooded batteries (or wet cell batteries) excel at delivering quick jolts of high current, making them ideal for starting a car. They can handle higher discharge rates than a sealed battery for a short period, like if you’ve accidentally left your headlights on. 

However, repeated deep discharges can damage the lead plates and shorten the battery’s lifespan. An FLA battery is also more susceptible to extreme temperatures, affecting performance.

2. Construction

Let’s review how an SLA battery (AGM) works compared to an FLA battery (flooded battery). 

A. AGM Battery

An AGM battery features thin fiberglass mats sandwiching lead plates. These mats absorb the electrolyte (sulfuric acid) and allow it to move to each battery plate to create electrical energy. 

B. Flooded Battery

A standard lead acid battery comprises lead plates submerged in a liquid electrolyte solution of sulfuric acid and water. Inside, the positive and negative plates are arranged in alternating layers, separated by insulating material. The electrolyte solution facilitates a chemical reaction between the lead plates, generating an electrical current.

3. Maintenance 

Some batteries need more care than others. 

A. AGM Battery

An SLA battery is practically maintenance-free. This sealed battery doesn’t need water top-ups.

B. Flooded Battery

Wet cell batteries require regular maintenance, including topping them with distilled water and cleaning the terminals to avoid corrosion. You’ll also need to check the FLA battery connections periodically.

4. Durability 

Let’s see how an AGM and a standard lead-acid battery stack up in terms of resilience. 

A. AGM Battery

The absorbed electrolyte in the fiberglass mat ensures they’re vibration-proof and less susceptible to bumps and jolts. This makes AGM batteries ideal for motorcycles and off-road vehicles.

B. Flooded Battery

While standard flooded batteries are durable, they tend to be more sensitive to environmental conditions. Additionally, lack of maintenance can shorten the battery life. 

However, they can last several years when well-maintained.

5. Cost

Let’s break down the price differences between these two batteries. 

A. AGM Battery

Because of its advanced technology, an AGM is pricier than a traditional car battery. Although its costs vary depending on factors like capacity and brand, you can expect to pay between $250 and $400 for a premium AGM battery. 

B. Flooded Battery

Flooded lead acid batteries are a mature technology with a lower price tag. Although brand and capacity affect the prices, a standard battery typically costs between $185 and $300.

6. Safety

Here’s how AGM and flooded batteries compare in terms of safety:

A. AGM Battery

An AGM’s fiberglass mats between each lead battery plate absorb the sulfuric acid to prevent acid leaks. Its shock resistance also makes this battery less prone to short circuits.

B. Flooded Battery

A wet cell battery comes with the risk of leaking battery acid. Moreover, flooded lead-acid batteries can emit gases when charging and discharging. Without good ventilation, these gases can cause an explosion.

After exploring the differences, let’s determine which battery type is right for your car.

Which Battery Type Should I Use?

Consider these factors to decide which car battery best aligns with your needs:

  1. Durability: As a sealed lead-acid battery, AGMs stand out for being rugged, reliable, and maintenance-free. 
  1. Energy needs: AGM batteries are better suited to cars with greater electrical loads and off-roading needs. However, standard flooded batteries are more than enough for most vehicles with moderate electrical demands.  
  1. Environmental conditions: AGM batteries perform better in extreme environmental conditions, like in a particularly hot, cold, or humid area.
  1. Installation flexibility: AGM batteries come out on top here since they can be mounted at an angle without worrying about spilling battery acid. 
  1. Cost: AGM batteries have a high upfront cost. This makes standard flooded batteries more cost-effective for regular cars. 

Next, we’ll see how to check if your car has an AGM or flooded battery. 

How Do I Know if I Have an AGM or Flooded Battery?

Here’s how you can tell what battery you have: 

Now, let’s review whether you can switch one out for another.

Can I Replace My Flooded Battery with an AGM Battery?

Yes, you can upgrade from a flooded to an AGM battery. Conversely, if you have an AGM battery, you could switch back to the flooded lead-acid battery. 

However, it’s important to note that AGM batteries are susceptible to overcharging, especially if connected to a battery charger for extended periods. Since AGM batteries need a controlled charging voltage, an inconsistent alternator or charging system could shorten the battery life. 

Consult your owner’s manual or a professional mechanic to verify if you can make the switch. 

What other battery types are there?
Read on to find out. 

Beyond AGM vs Flooded: Other Types of Batteries

Here are other types of batteries aside from the absorbed glass mat and wet cell battery:

AGM vs Flooded Battery: Finding Your Perfect Match 

While AGM batteries offer superior performance and low maintenance, they come at a premium price. On the other hand, flooded batteries are affordable but require regular maintenance. 

Need help choosing a battery?
Rest assured, AutoNation Mobile Service can recommend and install the best battery for your vehicle. 

We’re a mobile auto repair service with easy online booking, upfront pricing, and a 12-month | 12,000-mile repair warranty

Contact us, and our mechanics will install your new battery straight from your driveway.