Which Battery Is Used in the BMW 3 Series?

The BMW 3 Series typically uses an Absorbent Glass Mat (AGM) 12‑volt battery, with most modern models (roughly from the mid‑2000s onward) relying on an AGM starter battery sized around 80–105 Ah, while plug‑in hybrid versions add a high‑voltage lithium‑ion traction battery. However, the exact battery type, size, and specification depend on the model generation, engine, and whether the car is a hybrid.

Why the BMW 3 Series Battery Question Is More Complex Than It Sounds

As vehicle electronics have become more sophisticated, BMW has moved from conventional flooded lead‑acid batteries to AGM batteries and, in some variants, to advanced lithium‑ion packs. The 3 Series family now includes petrol, diesel, mild hybrid, and plug‑in hybrid models, each with different power and storage demands. Understanding which battery your specific 3 Series uses requires considering the model year (E90, F30, G20, etc.), engine variant, and whether the car has stop‑start or hybrid capability.

Main Battery Types Used in the BMW 3 Series

Across its generations, the BMW 3 Series has used three broad categories of batteries: traditional lead‑acid, AGM 12‑volt, and high‑voltage lithium‑ion packs in plug‑in hybrids. The following list outlines these main categories and what they are typically used for.

• Conventional flooded lead‑acid 12‑V battery: Used mainly in older 3 Series models before widespread adoption of start‑stop systems and heavy electrical loads.
• AGM (Absorbent Glass Mat) 12‑V battery: Standard in most modern 3 Series models with start‑stop technology and higher electrical requirements (E90 LCI onwards, F30, G20).
• Lithium‑ion high‑voltage traction battery: Used in plug‑in hybrid 3 Series models (e.g., 330e) to power the electric motor and enable electric‑only driving.

These three types cover the vast majority of BMW 3 Series configurations on the road today, with AGM batteries now the norm for the starter/auxiliary system and lithium‑ion packs reserved for electrified versions.

Battery Types by Generation and Model

E46 (1998–2006)

The E46 generation, sold roughly from 1998 to 2006, largely predates modern start‑stop systems and complex energy management. As a result, its battery specification is relatively straightforward.

• Battery type: Conventional flooded lead‑acid 12‑V battery.
• Typical capacity: Around 70–80 Ah, depending on engine (4‑cylinder vs 6‑cylinder) and equipment level.
• Location: In the trunk (boot), on the right side under the trim panel.
• Replacement flexibility: Less sensitive to exact type than newer cars; no electronic “battery registration” required from the factory.

For E46 owners, the main priority is matching physical size, terminal layout, and approximate capacity, rather than specific AGM requirements or system programming.

E90/E91/E92/E93 (2005–2013)

The E90 generation marked a transition to more advanced electrical systems and, in many markets and trims, the introduction of AGM batteries and start‑stop technology.

• Battery type: Mix of conventional lead‑acid and AGM, depending on model year and options; later and better‑equipped models frequently use AGM.
• Typical capacity: Roughly 70–90 Ah for most models.
• Energy management: Intelligent alternator control and battery monitoring begin to play a larger role.
• Battery registration: Required when replacing the battery on many models to ensure correct charging strategy.

On the E90 series, it is important to confirm whether the specific car is fitted with AGM from the factory; replacing an AGM with a cheaper flooded battery can cause premature failure and electrical issues.

F30/F31/F34 (2012–2019)

The F30 generation standardised the use of AGM batteries across most of the lineup, driven by start‑stop systems, increased electronic content, and stricter efficiency standards.

• Battery type: Primarily AGM 12‑V starter battery.
• Typical capacity: Around 80–90 Ah for many models, with higher capacities for larger engines or well‑optioned cars.
• Stop‑start: AGM used to withstand frequent cranking and partial‑state‑of‑charge operation.
• Battery registration: Mandatory when replacing to avoid overcharging or undercharging.

For F30‑series owners, “the battery” almost always means an AGM unit in the trunk, matched carefully to the original capacity and registered via diagnostic software after installation.

G20/G21 (2019–Present)

The current G20/G21 generation 3 Series builds on BMW’s energy management strategies and includes mild hybrids and plug‑in hybrids, complicating the battery picture further.

• 12‑V battery type: AGM 12‑V battery is standard for most combustion and mild‑hybrid versions.
• Typical 12‑V capacity: Frequently in the 80–105 Ah range, depending on engine and specification.
• Mild‑hybrid models: Add a small 48‑V lithium‑ion battery in addition to the 12‑V AGM battery.
• Plug‑in hybrid models (e.g., 330e): Feature a high‑voltage lithium‑ion traction battery plus the standard 12‑V AGM battery.

In the G20 era, the concept of “which battery” can refer to several different units in the same vehicle, especially in electrified variants that combine AGM and lithium‑ion packs.

Special Case: Plug‑In Hybrid BMW 3 Series (e.g., 330e)

Plug‑in hybrid versions of the 3 Series, notably the 330e, add a high‑capacity lithium‑ion battery to support electric driving alongside the combustion engine. This creates a dual‑battery architecture.

• 12‑V AGM battery: Handles conventional tasks like starting the engine (if applicable), running lights, infotainment, and control units.
• High‑voltage lithium‑ion traction battery: Powers the electric motor and stores energy recovered via regenerative braking and external charging.
• Capacity (traction battery): Varies by model year and market; recent 330e versions use a battery pack roughly in the mid‑teens of kWh (e.g., around 12–15 kWh usable).
• Location: The high‑voltage battery is typically packaged under the rear seat or trunk floor, which can slightly reduce luggage space.

For plug‑in hybrid owners, any question about “the battery” should be clarified, as maintenance, warranty coverage, and replacement costs differ significantly between the 12‑V AGM battery and the high‑voltage lithium‑ion unit.

Why BMW Uses AGM Batteries in Modern 3 Series Models

BMW’s move to AGM batteries in the 3 Series was driven by the need to support energy‑intensive features while ensuring durability. AGM technology offers several advantages over traditional flooded lead‑acid batteries.

• Better cycling durability: AGM batteries tolerate frequent charge/discharge cycles, essential for start‑stop systems and smart charging strategies.
• Spill‑proof design: The electrolyte is absorbed in glass mats, reducing leakage risk—important for batteries mounted inside the trunk.
• Higher power delivery: AGM units can deliver strong cranking current even at lower states of charge.
• Improved vibration resistance: More robust internal construction suits performance‑oriented vehicles and rough road conditions.

These advantages make AGM batteries well‑suited for the electrical architecture of modern BMW 3 Series cars, albeit at a higher cost compared with conventional batteries.

How to Identify the Correct Battery for Your Specific 3 Series

Because there is no single universal battery across all 3 Series variants, owners and buyers should verify the exact specification for their particular car. The following steps help narrow down the correct battery choice.

1. Check the existing battery label: Open the trunk and access the battery compartment; the label shows type (AGM or lead‑acid), capacity (Ah), and cold cranking amps (CCA).
2. Verify model year and code: Identify whether your car is an E46, E90, F30, G20, etc., since each generation has typical battery patterns.
3. Consult the owner’s manual: BMW lists approved battery types and capacities for each engine and equipment level.
4. Use the VIN in an online parts catalog: BMW’s official parts database or reputable third‑party parts sites can decode your exact original battery specification from the VIN.
5. Confirm AGM requirement: If your car has start‑stop or is a modern generation (F30, G20), assume AGM unless documentation clearly states otherwise.

Following these steps ensures you match the original engineering specification rather than relying on generic or approximate recommendations from non‑specialist sources.

Battery Replacement and Registration in BMW 3 Series

On newer 3 Series models, especially from the E90 generation onward, replacing the battery is not just a mechanical job; it also involves electronic configuration known as “battery registration.”

• What registration does: Informs the car’s energy management system that a new battery with specific capacity and type has been installed.
• Why it matters: Prevents incorrect charging strategies that can shorten battery life or trigger error messages.
• How it’s done: Using BMW diagnostic tools (e.g., ISTA) or compatible aftermarket scan tools that support BMW battery registration.
• When it’s essential: Whenever changing battery type (e.g., lead‑acid to AGM) or capacity, and on most late‑model 3 Series even with like‑for‑like replacement.

Skipping battery registration can lead to suboptimal performance and premature failure, so professional installation or access to proper diagnostic equipment is strongly recommended for modern 3 Series cars.

Summary

The BMW 3 Series does not use a single universal battery across all years and variants, but modern versions primarily rely on AGM 12‑volt starter batteries, with plug‑in hybrids adding a high‑voltage lithium‑ion traction pack. Earlier generations like the E46 used conventional lead‑acid batteries, while later models—from E90 through F30 to today’s G20—have increasingly standardised on AGM due to start‑stop technology and complex electrical systems. For any specific 3 Series, the definitive answer lies in checking the existing battery label, consulting the owner’s manual, or decoding the car’s VIN in an official or reputable parts catalog, and ensuring that any replacement battery is correctly registered in the vehicle’s electronics.

What type of battery is in my BMW?

BMWs typically use Absorbent Glass Mat (AGM) batteries, especially in models from 2005 onwards, due to their ability to support the vehicle’s advanced electronics and start-stop systems. Newer models and some M series cars may also use lithium-ion batteries, which have a higher energy density and are common in electric and hybrid vehicles. Conventional flooded lead-acid batteries are used in some older models or as supplemental batteries in EVs, but AGM and lithium-ion are the standard for modern BMWs. 
This video demonstrates the location of the battery in a BMW and how to access it: 57sJustin BuiceYouTube · Aug 18, 2022
Common battery types in BMWs

• AGM (Absorbent Glass Mat): The most common type for modern gasoline BMWs. These batteries are sealed, maintenance-free, and handle frequent charging cycles and high electrical demands better than traditional batteries. 
• Lithium-ion: Primarily found in electric and hybrid vehicles, though some performance models may use them as well. They offer higher energy density and efficiency. 
• Conventional flooded lead-acid: Used in older models. While less common in newer BMWs, they may be used as a supplemental battery in EVs to power other systems. 

Important considerations for BMW batteries

• Start-stop systems: Many modern BMWs have automatic start-stop technology that requires an AGM battery to handle the frequent re-cranking. 
• Advanced electronics: The high electrical demand from navigation, climate control, and other systems also necessitates a more robust battery like an AGM or lithium-ion. 
• Battery registration: When replacing an AGM battery, the new battery needs to be registered with the vehicle’s computer system so the car can properly manage charging. 

You can watch this video to learn how to register a new battery in a BMW: 44sFCP EuroYouTube · Dec 10, 2024

What type of battery does a BMW 328i use?

A BMW 328i uses either a lead-acid, AGM, or EFB battery, depending on the specific model year and its features like start-stop technology. The car requires a 12V battery, and common group sizes include H6, H7, H8, and 94R. It’s essential to check the size, type (AGM or flooded), and specifications (like CCA) of the battery currently in your vehicle before purchasing a replacement.
 
Battery types and sizes for a BMW 328i

• Lead-acid: A standard option for older models. 
• AGM (Absorbed Glass Mat): Often used in vehicles with start-stop systems for better performance and longevity. Many BMWs, even those not originally equipped with an AGM, can be upgraded to one, which can offer up to twice the lifespan of a traditional battery. 
• EFB (Enhanced Flooded Battery): Used in some Asian vehicles with start-stop technology and can be a good option for some BMWs. 

Common group sizes

• H6 (Group 48): Frequently found in many 328i models. 
• H7 (Group 94R): Used in many models, including some with start-stop systems. 
• H8 (Group 49): Found in older 328i models. 

Important considerations

• Match specifications: When replacing the battery, match the cold-cranking amps (CCA) and other specifications of the old battery, or choose a more powerful one with the correct group size. 
• Check your vehicle: The exact battery type and size can vary significantly between model years, so always check the battery in your car or use a vehicle-specific fit guide before buying. 
• Reset the computer: After replacing the battery in newer models, the vehicle’s computer system will need to be reset to properly register the new battery, often requiring professional service. 

What battery does a BMW 3 series key use?

Key then pull back the back cover to remove the outer housing using a small flathead screwdriver gently pull the battery out to remove the battery from the clips. Insert the new battery in the same.

Does BMW need a special battery?

Original BMW Batteries are specifically designed, built and tested to deliver a longer service life than conventional batteries. They’re optimized for the power demands of your BMW.