How do I know what type of battery my car battery is?

Most passenger cars rely on a 12-volt lead-acid battery, typically either a traditional flooded unit or an absorbed glass mat (AGM) design. The exact type matters for replacement, charging, and warranty. To be sure, inspect the battery label and the vehicle’s documentation—the marking will usually indicate AGM, EFB, or GEL, or note if it is a traditional flooded unit. Start-stop models are more likely to use AGM or EFB batteries.

On this guide, you’ll learn how to identify your battery type: where to look on the battery and in your owner's manual, how to recognize common markings, and how to verify the correct type before purchasing a replacement. A few newer vehicles may also use a 12-volt lithium-ion (LiFePO4) battery, which will be labeled accordingly and not interchangeable with standard lead-acid types.

Identify the Type from the Battery Label

Read the markings on the battery label to determine the technology, the part code, and the capacity. The presence of terms like AGM, EFB, GEL, or indications that the battery is Flooded will tell you the type. The OE sticker on the chassis or battery can also indicate the correct type for your vehicle.

Key markings to note

• Technology label: look for "AGM" (Absorbent Glass Mat), "EFB" (Enhanced Flooded Battery), "GEL" (gelled electrolyte), or "Flooded/Traditional" on the battery or packaging.


• Top vs. side labels: many AGM and EFB batteries have explicit labels on the top; traditional flooded units may have a label on the side and show venting or water-adding features.


• Capacity and model numbers: part numbers that you can cross-check with OE specifications.


• Branding and warranty terms: some brands differentiate within the same model family by technology type.

In most cases, a clear "AGM" or "EFB" marking on the label is a strong indicator. If you see only generic labels and removable caps, it’s more likely to be a flooded battery. Note that a growing share of new vehicles uses 12V lithium (LiFePO4) batteries for certain start-stop or hybrid systems; these will be branded as lithium and require special replacement and charging considerations.

Identify by Physical Cues and Design

When the label isn’t legible or you want another confirmation, inspect the battery’s physical features. Certain design cues align with different technologies.

What to look for

• Vent caps: Flooded lead-acid batteries typically have removable vent caps or a fill-level indicator; AGM and GEL batteries are sealed and do not have removable vent caps.


• Top construction: AGM batteries have a flat, sealed top; GEL batteries are also sealed but often show gel-related labeling; standard flooded batteries usually have accessible vents or caps for water addition.


• Weight: AGM batteries are typically heavier than flooded equivalents of the same size due to the glass mat material, though the difference can be modest.


• Labeling: Look for explicit terms like AGM, EFB, or GEL on the top or side labels.

If the battery is sealed and lacks removable caps or obvious venting, it is more likely AGM or GEL, but the exact type is confirmed by the label.

Confirm the Right Type for Replacement

Once you’ve identified the battery type, verify it against your vehicle’s requirements before buying a replacement. This ensures the correct charging profile and compatibility with features like start-stop systems.

Steps to verify

• Consult the owner's manual or the vehicle’s service manual for the recommended battery type (AGM vs Flooded vs EFB) and size, plus the required cold-cranking amps (CCA) and reserve capacity (RC).


• Cross-check the OE part number or battery code with the retailer's database or the OEM's site. If needed, use your VIN to confirm the exact specification for your model and engine variant.


• Shop with reputable auto parts retailers or the OEM’s parts portal to ensure the correct type for your model.


• Ask a mechanic or dealership if your car uses a start-stop system, a hybrid setup, or a high-performance variant, as incorrect battery type can affect charging and system functions.

Armed with the labels, manual references, and professional input, you’ll minimize the risk of mismatches and ensure reliable performance for years to come.

Summary

To determine your car battery’s type, start with the label on the battery and the vehicle’s documentation. Look for explicit markings such as AGM, EFB, or GEL, and verify the part number against OE specifications. If the label is unclear, consult the owner's manual, use VIN-based parts lookups, or ask a dealer or trusted mechanic. Keep in mind that a small but growing share of modern vehicles use 12V lithium-based batteries for certain systems, which require special handling and replacement procedures.

How to identify the battery type?

You can determine a battery's type by checking the label on the battery itself for a "group size" or chemistry (like Lead-acid, AGM, EFB, Gel, or Lithium-ion). If the label is worn or unreadable, consult your vehicle's owner's manual, look up your vehicle's make, model, and year online, or ask a professional at an auto parts store.
 
This video explains how to check the label on your battery: 57sLearnToDIY360YouTube · Dec 16, 2024
Check the battery label 

• Look for a group size: Car batteries use a BCI (Battery Council International) group size, a standardized classification for physical dimensions like height, width, length, and terminal location. 
• Look for chemistry type: Check for labels that specify the battery's chemistry, such as "AGM" (Absorbent Glass Mat), "EFB" (Enhanced Flooded Battery), "Gel," or "Lithium-ion". 
• Use recycling information: Sometimes, a battery's type can be found near the recycling symbols, often indicating the material like "Li-ion" for lithium-ion or "Pb" for lead-acid. 

If the label is unreadable or missing 

• Owner's manual: This is your next best resource, as it will contain specific information about the battery for your vehicle. 
• Online search: Search online for your vehicle's make, model, and year to find compatible battery types and specifications. 
• Use an online battery finder: Many auto parts retailers have tools on their websites where you can input your vehicle's information (year, make, model, VIN, or license plate) to get a list of compatible batteries. 
• Consult a professional: Visit an auto parts store or dealership. They can test your old battery or look up the correct type for you. 

How do I know if my battery is AGM or regular?

To identify if a car battery is regular or AGM, check the label for 'AGM' or 'Absorbent Glass Mat. ' AGM batteries have sealed tops with no removable caps, while regular batteries usually have removable vent caps. AGM batteries are more vibration-resistant and have lower self-discharge rates.

What happens if I put the wrong battery in my car?

Putting the wrong battery in your car can cause a wide range of problems, including electrical system damage, poor performance, and even physical damage to the car and battery itself. Issues vary depending on whether the battery is too large, too small, or has the wrong voltage, but can range from starting problems and accessory malfunction to frying critical components like the engine control unit.
 
Undersized battery

• Starting problems: The battery may not have enough Cold Cranking Amps (CCA) to start the engine, especially in cold weather. 
• Undercharging: The alternator may struggle to keep the battery charged, leading to a shortened battery lifespan and strain on the alternator. 
• Performance issues: You may experience reduced performance from electronic accessories like the A/C, headlights, and stereo. 

Oversized battery 

• Physical damage: The battery may not fit in the compartment, potentially causing structural damage to the battery case or the car itself.
• Electrical damage: It can cause voltage irregularities, leading to an overcharging condition that can damage the electrical system.
• Short-circuit risk: The terminals could touch other metal parts of the car, creating a short circuit. 

Wrong voltage

• Electrical system damage: Installing a battery with a different voltage than your car requires (e.g., a 24-volt battery in a 12-volt car) can immediately damage or "fry" sensitive electrical components like the engine control unit.
• Warning lights: A battery with a much lower voltage will not be able to power the vehicle, triggering warning lights and potentially making the car undrivable. 

Other potential issues

• Damage to other components: The stress on the electrical system can damage other components, such as fuses, diodes, and the alternator. 
• Start-stop system failure: Using an incorrect battery in a car with a start-stop system will cause the system to fail. 
• Safety risks: An incorrectly installed battery can lead to short circuits, melted wires, or even battery acid leakage if the case bursts. 

How do you tell what type of car battery you have?

You can tell what type of car battery you have by first checking the label on the battery itself for markings like "AGM" or "EFB". If the label is unreadable, the vehicle's owner's manual or an online search for your car's year, make, and model will provide the correct information. For physical size and terminal type, look for the BCI "Group Size" printed on the battery label.
 
1. Check the battery label 

• Look for a sticker on the battery case. It will have printed information, such as the battery's chemistry type (e.g., "AGM," "EFB," or "Lead-acid"). 
• You will also find a "Group Size" on the label, which is a code for physical dimensions and terminal type (e.g., 24F). 
• You may also see other specifications like Cold Cranking Amps (CCA). 

This video explains what the labels on a car battery mean: 1mJeremy FieldingYouTube · Jun 11, 2018
2. Consult the owner's manual

• If the label is worn or unreadable, the owner's manual for your vehicle will have a section on the battery that specifies the correct type, size, and CCA requirements. 

3. Use online tools 

• Websites for auto parts stores often have a "battery finder" tool where you can enter your vehicle's year, make, and model to see compatible battery types. 

4. Ask a professional

• If you are still unsure, an employee at an auto parts store or a mechanic can quickly identify the correct battery for your car.