What Size Battery Does a BMW E46 Use?

A typical BMW E46 (1998–2006 3 Series) most commonly uses a Group 48 / H6 or Group 94R / H7 12‑volt battery, with capacities usually between about 70–90 Ah and a cold cranking amps (CCA) rating in the 650–800+ range, depending on engine, equipment and market. However, the exact recommended size can vary slightly by model, year, engine, and climate, so checking the original spec sticker or owner’s manual is essential.

How BMW Specified Batteries for the E46

The BMW E46 platform covered the 3 Series built roughly from 1998 to 2006, including sedans, coupes, wagons and convertibles, with engines ranging from four‑cylinder diesels to performance‑focused six‑cylinder petrol units in the M3. Across this broad range, BMW used conventional 12‑volt lead‑acid batteries, but the physical size, capacity and CCA differed slightly to match the electrical load and regional standards.

Common Battery Group Sizes for the BMW E46

For owners and buyers today, the most relevant information is the industry “group size” (North American BCI standard) or the European DIN/EN size codes. The E46 generally falls into a narrow band of compatible sizes that fit the battery tray and meet the amperage needs of the car.

The following list outlines the most common battery group sizes used or recommended as replacements for BMW E46 models, with typical specs and notes for each.

• Group 48 / H6 – One of the most widely used sizes in E46 replacements. Approx. dimensions: 12.1″ x 6.9″ x 7.5″ (306 x 175 x 190 mm). Typical capacity: 70–80 Ah. Typical CCA: ~680–800 A. Fits many 320i/325i/328i/330i models and is a common “standard” upgrade size.
• Group 94R / H7 – Slightly larger capacity and often used where higher load or colder climates are a factor. Approx. dimensions: 12.4″ x 6.9″ x 7.5″ (315 x 175 x 190 mm). Typical capacity: 80–90 Ah. Typical CCA: ~750–850+ A. Popular choice for six‑cylinder cars and M3 owners wanting a robust starting reserve.
• Group 47 / H5 – A bit smaller and sometimes found as an economy replacement, or in markets where lower capacity is acceptable. Approx. dimensions: 9.6″ x 6.9″ x 7.5″ (242 x 175 x 190 mm). Typical capacity: 60–65 Ah. Typical CCA: ~550–650 A. It may physically fit but can be marginal if the car sees heavy accessory use or cold winters.
• DIN/EN European codes (e.g., 70–90 Ah batteries) – In Europe and many other regions, batteries are sold by Ah rating and physical specs rather than “Group” numbers. A typical OEM‑style E46 battery is an approximately 80 Ah, 12 V unit with around 700–800 A EN CCA and dimensions around 315 x 175 x 190 mm.

In practice, most E46 owners today end up with a Group 48/H6 or Group 94R/H7 battery, as these sizes closely match the original BMW fitment, provide sufficient electrical capacity, and are widely stocked by major brands.

OEM vs. Replacement: What BMW Originally Fitted

From the factory, BMW equipped the E46 with branded lead‑acid batteries that often carried labels such as 70 Ah, 80 Ah or 90 Ah, depending on engine and equipment levels. While exact part numbers and markings differ by year and region, the original batteries were broadly equivalent to modern Group 48/H6 or 94R/H7 units in size and performance.

Typical Factory Specifications

BMW’s original E46 batteries were selected to meet the demands of fuel injection systems, onboard electronics, climate control, and—on higher‑spec cars—navigation, power seats and upgraded audio. Though the E46 predates modern start‑stop systems and AGM‑only requirements, the OEM batteries were still relatively high in capacity for their time.

The following list explains the main performance parameters that BMW’s factory E46 batteries generally met or exceeded.

• Voltage: 12 V nominal, standard for passenger cars.
• Capacity (Ah): Typically 70–90 Ah depending on engine and market. Six‑cylinder and high‑equipment models were more likely to get 80 Ah or 90 Ah units.
• Cold Cranking Amps (CCA): Usually in the range of roughly 650–800+ A (EN/SAE), enough to assure reliable starts in cold European and North American climates.
• Chemistry: Conventional flooded lead‑acid, with AGM appearing more as a modern upgrade than an original requirement for standard E46 models.
• Physical size: Roughly equivalent to what is now sold as Group 48/H6 or 94R/H7 in North America, fitting into the right‑rear trunk battery well.

Because the original factory batteries closely match today’s common replacement sizes, modern Group 48/H6 and 94R/H7 units are generally considered direct and safe substitutes when bought from reputable brands.

Differences Between Engines and Models (320i vs. 330i vs. M3)

Not every E46 variant was specified with exactly the same battery from new. Engine size, optional equipment and even body style could influence which capacity BMW installed at the factory, although the physical external size often remained similar.

Four‑Cylinder vs. Six‑Cylinder Models

E46 four‑cylinder models (such as certain 316i/318i/320d variants in some markets) commonly required slightly less cranking power than their six‑cylinder petrol siblings. While many owners still choose a mid‑range Group 48/H6 for convenience, some of these cars were factory‑equipped with slightly lower‑capacity units.

The following list highlights the general trends observed between different E46 engine types and their ideal battery specs.

• Four‑cylinder petrol and small diesels: Often adequately served by a 70–75 Ah battery with ~650–700 A CCA (Group 48/H6 or equivalent). This gives a safety margin without overspending on capacity.
• Six‑cylinder petrol models (e.g., 325i, 328i, 330i): Typically better matched to 80–90 Ah batteries with ~700–800 A CCA (Group 48/H6 or 94R/H7). These engines, plus common options like heated seats and premium audio, draw more power.
• Diesel variants (where applicable, such as 320d, 330d): Diesels often benefit from higher CCA because of compression ratios and glow plug operation. Many owners opt for the larger Group 94R/H7 with strong CCA for reliable cold starts.
• BMW E46 M3: The high‑performance S54 engine has more demanding cold‑start requirements, and many owners choose an 80–90 Ah, high‑CCA battery (often 94R/H7) to balance performance and durability.

While you can sometimes install a smaller or larger battery than fitted originally, staying close to the original Ah and CCA levels for your specific engine generally makes for fewer headaches, particularly in cold climates.

How to Confirm the Correct Battery Size for Your Specific E46

Because the E46 range is over 20 years old, many cars no longer carry their original battery, and previous owners may have installed incorrect sizes. To avoid guesswork, it’s important to verify the right fitment for your particular car rather than relying solely on model‑wide averages.

Checking Documentation and the Car Itself

Drivers can use both official documentation and physical inspection of the car to confirm the correct battery size. BMW usually provides at least one of several reference points to identify the recommended capacity and type.

The following list outlines the most reliable ways to confirm the correct battery for your specific BMW E46.

1. Owner’s manual: Look in the “Technical Data” or “Battery” section for recommended battery capacity (Ah) and sometimes CCA. The manual may list specific BMW part numbers or minimum ratings.
2. Trunk battery label: Many E46 models have an information sticker near the battery compartment (right‑rear of the trunk) indicating recommended capacity and type. Compare this with your current battery’s label.
3. Existing battery markings: If the current battery is the correct type, its label will show Ah rating, CCA and a code such as H6/H7 or DIN dimensions. Use this as a reference when shopping for a replacement.
4. VIN‑based lookup: Dealers and some online parts catalogs can use your VIN to identify the original BMW battery part number and its equivalent specifications.
5. BMW parts catalog (ETK/RealOEM‑type sites): These catalogues let you select your car by model, year and engine to display factory battery part numbers and general specifications.

Cross‑checking at least two of these sources reduces the chance of fitting an undersized or physically incompatible battery, and helps ensure that the replacement meets BMW’s original design criteria.

Key Technical Considerations: Beyond Just “Will It Fit?”

Physical size is only part of the story. An E46 battery must also deliver enough electrical performance to crank the engine, support the car’s electronics and survive the conditions in which it will be used. Choosing a battery only by size without attention to specs can lead to poor cold starting or premature failure.

Capacity (Ah), CCA, and Terminal Layout

Three main factors—amp‑hour capacity, cold cranking amps and terminal configuration—determine whether a battery is truly suitable for an E46 beyond merely sitting in the tray.

The following list explains the main technical points E46 owners should check when selecting a new battery.

• Amp‑hour capacity (Ah): Stick close to BMW’s recommendation (typically 70–90 Ah). Lower Ah can work but may drain faster if the car sits or has added electronics.
• Cold cranking amps (CCA): Aim for at least 650 A, and preferably 700+ A in colder climates or on larger engines. Higher CCA improves cold starts but also tends to cost more.
• Terminal layout and polarity: E46 models generally use a battery with the positive terminal on the right side (as you face the terminals). Group 94R (“R” for reversed) and H6/H7 patterns match this layout; ensure any replacement has the correct polarity orientation.
• Hold‑down and case type: The battery must have a compatible base so it can be clamped securely in the E46 trunk tray. A loose battery is both dangerous and damaging to the car.
• Chemistry (flooded vs. AGM): Standard E46 models were not specifically designed for AGM only, but AGM batteries are a common upgrade because they resist vibration and deep discharge better. If upgrading to AGM, match the original Ah and CCA ratings, and ensure your charger is AGM‑compatible.

Matching these parameters to BMW’s original expectations provides a balance of reliable starting, long life and protection for the car’s electrical system, rather than merely filling the available space.

Installation Notes and Coding Concerns

Unlike newer BMW platforms with intelligent battery sensors and required “battery registration,” the E46 generation is comparatively simple from an electronics standpoint. That said, certain practices still matter when replacing the battery.

Replacing an E46 Battery Correctly

Even without coding requirements, E46 owners should observe some basic precautions to avoid damage to the car’s electrical components and to ensure the new battery delivers its full potential.

The following list outlines best‑practice steps and considerations when installing a new battery in a BMW E46.

1. Maintain power if possible: Using a memory saver in the 12 V socket can help preserve radio presets and clock settings, though the car will usually tolerate a full power down without major issues.
2. Disconnect negative first, reconnect negative last: Always remove the negative (ground) terminal before the positive to reduce the risk of accidental short circuits; reverse the order when reconnecting.
3. Inspect and clean terminals: Check for corrosion on the battery clamps and cables; clean them with a brush and appropriate cleaner to ensure good contact with the new battery.
4. Secure the battery: Properly use the factory hold‑down bracket so the battery cannot move under acceleration or over bumps, preventing cable stress and potential shorting.
5. No coding typically required: The E46 generally does not require battery registration or coding after replacement, unlike many later BMW models. However, checking for any stored faults with a diagnostic scanner is still good practice.

Following these basic steps can extend the life of the new battery and help avoid electrical gremlins that might otherwise be misdiagnosed as more serious faults.

Summary

A BMW E46 3 Series typically uses a mid‑size 12‑volt lead‑acid battery equivalent to Group 48 / H6 or Group 94R / H7, usually in the 70–90 Ah and 650–800+ CCA range, depending on engine and equipment. Four‑cylinder models can often get by with slightly lower capacities, while six‑cylinder, diesel and M3 versions benefit from stronger 80–90 Ah units. To confirm the exact recommended size for a given car, owners should check the owner’s manual, trunk sticker, existing battery label or a VIN‑based parts catalogue. Matching BMW’s original specifications for capacity, CCA, polarity and mounting style is the safest route to reliable starting and long battery life in an aging but still widely loved E46.