Home FAQ

Does my car require an AGM battery?

The short answer is: it depends on your car's make, model, and year. Some vehicles are designed to use an Absorbent Glass Mat (AGM) battery, while others can use a standard lead-acid battery. The type of battery your car needs is determined by the vehicle's electrical system and power requirements.

What is an AGM Battery?

An AGM (Absorbent Glass Mat) battery is a type of lead-acid battery that uses a different internal construction compared to a traditional lead-acid battery. AGM batteries have a number of advantages, including increased vibration resistance, faster recharging, and better performance in extreme temperatures. They are often used in vehicles with more advanced electrical systems, such as those with start-stop technology, regenerative braking, or high-powered audio systems.

Determining if Your Car Needs an AGM Battery

To determine if your car requires an AGM battery, you should consult your owner's manual or contact your vehicle's manufacturer. They will be able to provide the specific battery requirements for your make, model, and year. Some key factors that may indicate the need for an AGM battery include:

Presence of start-stop technology or regenerative braking

High-powered electrical systems, such as advanced audio or entertainment systems

Frequent use of electrical accessories, such as heated seats or mirrors

Driving in extreme temperatures, either hot or cold

Frequent towing or hauling heavy loads

If your vehicle is equipped with any of these features or experiences these conditions, it may be recommended or required to use an AGM battery.

Replacing Your Battery

When it's time to replace your car's battery, it's important to use the correct type. Using the wrong battery can lead to issues with your vehicle's electrical system and may even cause damage. If your car requires an AGM battery, be sure to replace it with a compatible AGM model. Consult your owner's manual or speak with a qualified mechanic to ensure you get the right battery for your vehicle.

Can I use a regular battery instead of an AGM?

You can, but it is not recommended because a regular flooded battery will likely have a shorter lifespan and may not perform as well as an AGM battery in modern vehicles. AGM batteries are designed for high-demand applications like those with start-stop systems, which rely on the battery to provide more frequent starts and handle a high electrical load while the engine is off. A regular battery may be damaged by this constant cycling, leading to premature failure.
Why it's not recommended

Shorter lifespan: Regular batteries are not built to handle the deep and frequent discharges that occur with start-stop technology, which can lead to sulfation and damage.
Reduced performance: Your vehicle's start-stop system may not function correctly or reliably with a regular battery.
Safety concerns: Regular batteries release gases during charging, which can be a safety hazard in enclosed spaces. AGM batteries are sealed, which minimizes this risk.
Potential system damage: Modern vehicles are designed with specific charging systems for AGM batteries. Using a regular battery can potentially damage the vehicle's electrical system.

When a regular battery might work

Older vehicles: If your vehicle does not have a start-stop system, an older vehicle may be able to use a regular battery.
Applications without high electrical loads: In applications that do not have a high, constant electrical demand while the engine is off, a regular battery might suffice.
When cost is the main concern: If you are on a very tight budget and your vehicle is older, a regular battery might seem appealing, but the risk of premature failure and potential performance issues is high.

The bottom line
It is best to replace an AGM battery with another AGM battery, especially in modern vehicles. The difference in price is often minimal, and using the correct battery type will ensure reliable performance and longevity. If you must use a regular battery, be prepared for a shorter lifespan and potential issues with your vehicle's electrical systems.

Does my car really need an AGM battery?

AGM is required when the battery is inside the passenger compartment. You don't want that spilling. It's a safety measure. So if your battery is behind some panel within the passenger compartment, that's a 100% indication that you should go AGM.

What is the main disadvantage of an AGM battery?

The main disadvantages of an AGM battery are their higher upfront cost and sensitivity to overcharging. They are more expensive than traditional batteries due to their advanced design and materials, and overcharging can lead to premature failure. Additionally, they require a specific charger designed for AGM batteries, and some older testers cannot accurately test them.

Higher cost: AGM batteries have a higher initial purchase price compared to flooded lead-acid batteries.
Sensitivity to overcharging: They can be permanently damaged by overcharging, which can cause heat, pressure buildup, and electrolyte dry-out.
Requires specific charging equipment: They need a charger specifically designed to handle their voltage and charging requirements to avoid damage and ensure proper performance.
Compatibility issues: Some older battery testers may not be able to accurately test them, and some vehicle charging systems may not be compatible without modification.

What happens if I charge my AGM battery with a normal charger?

Charging an AGM battery with a normal charger can cause irreversible damage by leading to overcharging, which overheats the battery, boils the electrolyte, and can pop its safety valve. This results in electrolyte loss, internal component damage, shortened lifespan, and potential failure. Using a charger designed for standard lead-acid batteries can also undercharge the AGM battery, leading to sulfation and reduced capacity.

Effects of improper charging

Overcharging: Standard chargers may not have the precise voltage regulation that AGM batteries require.
- This can push the voltage higher than an AGM can safely handle (above 15 volts), leading to overheating.
- The excess heat causes the water in the electrolyte to evaporate, which the sealed AGM cannot have replaced.
- This can also cause the internal pressure to build up and pop the safety valve.
Undercharging: A charger that is not compatible may not provide the correct voltage profile for the AGM battery, leading to undercharging.
- This results in a battery that is never fully charged.
- Undercharging can also cause sulfation on the battery plates, reducing its ability to accept a charge and shortening its lifespan.

How to charge an AGM battery safely

Use a charger specifically designed for AGM batteries or a "smart" charger with an AGM setting.
Ensure the charger's voltage output is within the recommended range for AGM batteries, typically 14.4 to 14.8 volts for charging.
Charge at a slower rate, often around 10% of the battery's amp-hour rating (e.g., a 50Ah battery should charge at 5 amps).

Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.