What Kind of Battery Does a 2011 BMW 328i Take?

The 2011 BMW 328i typically uses a Group 94R (also called H7) AGM or flooded lead‑acid battery, around 80–90 Ah, with the positive terminal on the right and requires electronic registration in the car after replacement. Below is a detailed breakdown of the specifications, options, and what owners should know before buying or installing a new battery.

Understanding the 2011 BMW 328i Battery Requirements

The 2011 BMW 328i (E90/E91/E92/E93 generation) is equipped with an Intelligent Battery Sensor (IBS) and a charging system that expects a specific type, size, and capacity of battery. Using an incorrect battery—or failing to register the new one in the car’s computer—can lead to charging issues, shortened battery life, or electrical faults.

The Standard Battery Type and Specifications

Most 2011 BMW 328i models sold in North America and Europe came from the factory with a large, trunk-mounted battery designed for high electrical loads and cold-weather starting.

Core Specifications

The following points outline the typical OEM-style specifications for a 2011 BMW 328i battery.

• Group size: 94R (also known as H7 in DIN/EN sizing)
• Terminal orientation: Reverse (positive terminal on the right when terminals are closest to you)
• Voltage:

• Capacity (Ah): commonly 80–90 Ah from the factory
• Cold Cranking Amps (CCA): typically in the 720–850 CCA range, depending on brand and exact model
• Chemistry: Either AGM (Absorbent Glass Mat) or conventional flooded lead‑acid, depending on original equipment and options
• Location: Trunk/right rear side, under the trim panel

Together, these specifications describe the physical size, electrical capability, and orientation that a replacement battery must meet so it fits securely and functions correctly with the BMW’s electrical and charging systems.

AGM vs Flooded Battery: What Should You Use?

BMW used both conventional flooded and AGM batteries in the E90-generation 3 Series, depending on trim, region, and options such as start-stop or high electrical demand. Choosing the correct chemistry is important for both performance and longevity.

When an AGM Battery Is Recommended

The following scenarios generally make an AGM battery the preferred or required choice for a 2011 BMW 328i.

• Original battery was AGM: You should replace it with another AGM to match the charging profile programmed in the car.
• Frequent short trips: AGM handles partial charge cycles better and is more resistant to sulfation.
• Extreme temperatures: AGM batteries typically perform more reliably in very cold or very hot climates.
• High electrical load: Cars with many accessories, aftermarket audio, or heavy use of electronics often benefit from AGM stability.
• Start/stop or advanced energy management (in some markets): When present, AGM is usually the required type.

If your car originally came with an AGM battery, staying with AGM maintains the intended charging behavior and helps avoid premature wear or electrical issues.

When a Flooded (Conventional) Battery May Be Used

Some 2011 328i models were fitted from the factory with conventional flooded lead‑acid batteries. In those cases, owners may continue to use that type under certain conditions.

• Original fitment was flooded: Keeping the same type avoids the need to re-code the vehicle for a new chemistry.
• Moderate climate: Standard flooded batteries can perform adequately where temperatures are not extreme.
• Budget-conscious replacement: Flooded batteries are generally cheaper than AGM, while still functional if properly specified.
• Normal driving patterns: For highway-heavy, longer trips, a quality flooded 94R battery often provides acceptable life.

Using a flooded battery where a flooded one was originally fitted is acceptable, provided the capacity and group size match, and the new battery is properly registered in the car’s system.

Physical Size and Fitment (Group 94R / H7)

Battery “group size” ensures the new battery fits the factory tray and can be clamped down correctly. For the 2011 BMW 328i, the key designation is 94R, also known as H7 in European sizing.

Why Group 94R Matters

The following characteristics define why the 94R/H7 standard is crucial for a proper fit and safe installation.

• Dimensions: Roughly 12.4 in (315 mm) long, 6.9 in (175 mm) wide, and 7.5 in (190 mm) high (varies slightly by brand)
• Terminal layout: Reverse arrangement with the positive post on the right, matching BMW’s cable lengths and routing
• Mounting points: Compatible with the factory battery clamp and tray in the trunk
• Vent port: Designed to accept a vent tube, important for batteries installed inside the vehicle

By staying with the 94R/H7 group, you avoid issues with cable reach, loose mounting, or interference with trunk panels and covers.

Battery Registration and Coding in a BMW 328i

Unlike many older cars, the 2011 BMW 328i monitors battery condition and adjusts its charging strategy accordingly. After installing a new battery, you must “register” it with the car’s system, and sometimes recode the capacity and type if those change.

What Battery Registration Does

Battery registration is a software procedure performed via diagnostic tools. It serves several technical purposes.

• Resets battery monitoring: Tells the car that a new battery has been installed so it can track aging and charge levels accurately.
• Adjusts charging behavior: Ensures the alternator and energy management system do not overcharge or undercharge a fresh battery.
• Prevents warning messages: Helps avoid spurious battery or charging system errors on the dashboard.
• Optimizes battery life: Better charging control means the new battery typically lasts longer.

Failing to register a new battery can lead to reduced battery life, intermittent electrical issues, and incorrect diagnostic readings over time.

When Coding Is Also Required

In some situations, you must go beyond simple registration and update the battery parameters in the car’s software.

• Changing chemistry: Switching from flooded to AGM (or vice versa) requires updating the battery type in the car’s coding.
• Changing capacity: If you move from, for example, 80 Ah to 90 Ah or 70 Ah, the car must be told the new capacity.
• Non-standard replacement: Any deviation from the original BMW spec generally merits a coding check.
• Professional tools: Coding is usually done with BMW-specific software (ISTA, ISTA/D, or well-supported aftermarket tools).

Proper coding ensures the intelligent charging system is tuned to your exact battery, protecting both the new battery and the vehicle’s electronics.

Common Aftermarket Battery Options

Several major brands offer suitable Group 94R/H7 batteries compatible with the 2011 BMW 328i, often with direct-fit designs and proper venting for trunk installation.

Examples of Compatible Batteries

The following examples illustrate typical replacement choices; availability can vary by region and retailer.

• AGM 94R/H7 batteries: Products such as Interstate AGM, Bosch AGM, Exide AGM, or AutoZone’s Duralast H7-AGM, sized for BMW fitment.
• Flooded 94R/H7 batteries: Standard lead‑acid models such as Interstate 94R, Bosch 94R, or similar private-label options at major auto parts stores.
• OEM-equivalent brands: BMW-branded replacement batteries (often manufactured by companies like Exide or Varta in Europe), sold at dealerships.
• Premium European brands (where available): Varta Silver Dynamic AGM or Banner batteries with H7/94R specifications.

These aftermarket options typically match the physical group size and electrical specifications required and can be used as long as installation, registration, and, if needed, coding are correctly performed.

How to Confirm the Correct Battery for Your Specific 328i

Because equipment and original battery types can vary with trim level and market, it’s wise to double-check your specific vehicle before purchasing a replacement.

Steps to Verify the Correct Battery

The following steps help ensure you match the battery to your exact 2011 328i configuration.

1. Inspect the existing battery label: Look for “AGM” or “VRLA” markings, the Ah rating (e.g., 80 Ah), and any BMW part number.
2. Check the group size: It should show 94R or H7; if not, confirm dimensions and compatibility with the battery tray.
3. Consult the owner’s manual: BMW documentation often lists recommended capacities and types for your model.
4. Use your VIN at a dealer or parts site: A BMW service department or reputable online catalog can decode your VIN and show the original battery spec.
5. Ask about registration/coding: If buying from a workshop or dealer, confirm they will register and, if needed, code the new battery.

Taking these steps before you buy avoids return hassles, improper fitment, and the risk of installing a battery that is electrically mismatched to your vehicle.

Key Takeaways and Practical Advice

Choosing a correct battery for a 2011 BMW 328i is not just about physical size; it also involves electrical compatibility, chemistry, and electronic setup.

Main Points Owners Should Remember

The following key points summarize what matters most when replacing the battery in this model.

• The typical spec is a Group 94R (H7), 12 V, ~80–90 Ah battery with reverse terminals and trunk venting.
• Many cars use an AGM battery; if yours did, it is best to replace it with AGM of similar capacity.
• Battery registration with the car’s control unit is required whenever a new battery is installed.
• Coding may be needed if you change chemistry (AGM vs flooded) or significantly alter battery capacity.
• Using the wrong type or skipping registration can shorten battery life and cause electrical issues.

By focusing on these practical factors, owners can ensure a reliable battery replacement that works harmoniously with the BMW’s sophisticated electrical system.

Summary

A 2011 BMW 328i generally requires a Group 94R/H7 12‑volt battery, commonly around 80–90 Ah, with the positive terminal on the right and proper venting for trunk installation. Many examples were fitted with an AGM unit from the factory, and replacing like-for-like is the safest choice. Whatever brand or chemistry you select, the crucial steps are matching the physical group size and capacity, installing the battery securely, and then performing battery registration—and, if needed, coding—so the car’s energy management system is calibrated to the new battery. This combination of correct hardware and proper electronic setup delivers optimal performance, reliability, and battery lifespan in the 2011 BMW 328i.