What Size Battery Does a BMW 320i Have?

The typical BMW 320i uses a 12‑volt AGM (Absorbent Glass Mat) battery in the Group 47 (H5), Group 48 (H6), or Group 49 (H8) size range, with capacities commonly between 70 Ah and 95 Ah and cold cranking amps (CCA) often around 720–850, depending on model year, engine, and equipment. This article explains how battery size varies across generations, what the main specifications mean, and how to select the correct replacement.

Why “Battery Size” Is Not One Single Number

When drivers ask what size battery a BMW 320i has, they usually mean physical dimensions, but in practice BMW specifies a combination of factors: physical group size, capacity in ampere‑hours (Ah), cold cranking amps (CCA), and battery type (AGM vs flooded). Modern 3 Series models, especially with start‑stop systems and energy‑intensive electronics, are designed to run on AGM batteries matched to the car’s charging strategy.

Typical Battery Sizes by BMW 320i Generation

BMW has produced the 320i across several generations of the 3 Series, and while the general battery concept remains similar, exact sizes and specifications can vary by year, region, and options such as start‑stop or cold‑weather packages.

F30/F31 Generation (Approx. 2012–2019)

The F30/F31 320i (sedan and touring) is among the most common modern 320i models on the road. It typically uses a higher‑capacity AGM battery to support start‑stop and various electronic systems.

The following list outlines the most common battery specifications found in F30‑era 320i models.

• Voltage: 12 V
• Battery type: AGM (Absorbent Glass Mat), not conventional flooded in most markets
• Common group sizes:
  

  • Group 48 (H6) – medium size, often around 70–80 Ah
  • Group 49 (H8) – larger size, often around 90–95 Ah

• Typical capacity: roughly 70–95 Ah, depending on equipment and original spec
• Typical CCA (cold cranking amps): around 720–850 CCA
• Location: trunk (boot), usually on the right‑hand side under a trim panel
• Registration required: new batteries must be registered/coded in the car’s ECU using BMW diagnostic software or compatible tools

In practice, most F30 320i owners will encounter either a Group 48/H6 or Group 49/H8 AGM battery, and staying with the same group and similar Ah rating as the original is the safest choice.

G20 Generation (Approx. 2019–present)

The G20 320i continues BMW’s move toward intelligent energy management, and the electrical system is designed around AGM batteries (with some models having supplementary 48 V mild‑hybrid systems in other engine variants, though this is less common on 320i trims in many markets).

The following list summarizes typical G20 320i battery characteristics.

• Voltage: 12 V main battery (separate from any 48 V mild‑hybrid components in other variants)
• Battery type: AGM is standard on most modern 320i variants with start‑stop
• Common group size:
  

  • Group 48 (H6) – frequently used as the main battery
  • Group 49 (H8) – used in higher‑load configurations or certain markets

• Typical capacity: approximately 70–90 Ah
• Typical CCA: often in the 720–850 CCA range, similar to F30
• Location: trunk area, again under trim panels
• Registration/coding: mandatory after replacement to ensure correct charging strategy and battery life

For G20 320i owners, the battery dimensions and type are broadly similar to the F30’s, and following the original BMW spec label in the trunk is key to matching the size and performance profile.

Older 320i Models (E90/E46 and Earlier)

Earlier 320i generations, like the E90 (mid‑2000s) and E46 (late 1990s to mid‑2000s), often used conventional flooded lead‑acid batteries or lower‑spec AGM units, typically with slightly lower capacity requirements than modern counterparts.

The next list highlights the general tendencies for older 320i battery sizing.

• E90 320i (approx. 2005–2012):
  

  • 12 V battery, commonly in the 70–90 Ah range
  • Often Group 48 (H6) or similar European DIN sizing
  • AGM became more common over time, especially with start‑stop

• E46 320i (approx. 1998–2005):
  

  • 12 V flooded lead‑acid or AGM, depending on market and options
  • Capacity often around 60–80 Ah
  • Physical size comparable to modern mid‑size automotive batteries

• Very early 3 Series 320i (E21/E30):
  

  • Simpler electrical loads and lower Ah requirements
  • Conventional lead‑acid batteries sized according to older DIN standards

While these older models are less demanding electrically, they still require the correct size and terminal orientation, so matching the original spec or consulting a parts catalog remains important.

How to Identify the Correct Battery Size for Your Specific 320i

Because BMW 320i models span many years and markets, the most reliable way to determine the exact battery size for your car is to check the existing unit and the car’s documentation rather than relying on a single universal number.

Check the Battery Label and Vehicle Documentation

Your current battery and the car’s original documentation provide key information that ensures any replacement fits and functions properly with the BMW’s electrical system.

The following list explains what to look for when checking your 320i’s existing battery and paperwork.

1. Look at the label on the existing battery:
   

   • Find capacity in Ah (e.g., 80 Ah, 90 Ah)
   • Note the CCA rating (e.g., 800 A EN)
   • Confirm AGM vs flooded type
   • Check physical group size if listed (e.g., H6 / L3 / Group 48)

2. Check the BMW build sheet or service documentation:
   

   • Look for options related to start‑stop system or AGM battery
   • Some service invoices list the original BMW battery part number and capacity

3. Use a VIN‑based parts catalog:
   

   • Enter your VIN into an official BMW parts system or reputable online catalog
   • Confirm the specified Ah rating and recommended battery type

4. Check the battery tray and mounting hardware:
   

   • Ensure the replacement physically matches the tray dimensions
   • Verify the hold‑down and vent positions work with the chosen group size

Following these steps helps you match both the physical size and the electrical characteristics of the factory battery, which is particularly important in a BMW due to its sensitive charging management.

Why AGM Batteries Are Common in Modern 320i Models

Modern BMW 320i variants are engineered with sophisticated energy management, regenerative charging, and stop‑start technology, all of which place higher demands on the battery than older systems. AGM batteries are better suited to this environment than conventional flooded designs.

Key Advantages of AGM in a BMW 320i

The features of AGM technology align closely with BMW’s requirements for durability, reliability, and performance under variable load and frequent cycling.

• Deep‑cycle capability: AGM batteries handle repeated partial discharge and recharge cycles better, ideal for start‑stop traffic.
• Higher charge acceptance: They absorb charge more efficiently, which works well with regenerative braking strategies.
• Vibration resistance: The glass mat construction improves durability under vehicle vibration.
• Spill‑proof design: Safer in trunk installations, where leaks could damage trim and electronics.
• Longer service life (when correctly managed): Properly coded and charged AGM batteries generally outlast equivalent flooded units in the same usage scenario.

Because the car’s alternator and control modules are tuned for AGM performance, substituting a cheaper flooded battery can lead to premature failure or erratic electrical behavior.

Battery Registration and Coding: An Essential Step

For F30, G20, and many E90‑era 320i models, simply swapping the battery is not enough; the new battery must be registered in the car’s ECU so the charging strategy is recalibrated to the battery’s condition and capacity.

What Registration Does and Why It Matters

Battery registration tells the vehicle that a new battery with a certain capacity and type has been installed, allowing the control units to reset their assumptions about battery age and adjust charging behavior.

The list below outlines the main reasons registration is required after installing a new battery in a 320i.

• Resets battery age calculations: Prevents the ECU from under‑ or over‑charging by assuming the battery is old when it is actually new.
• Adapts to capacity changes: If you move from, for example, 70 Ah to 80 Ah or 90 Ah, the system can adjust its strategy.
• Protects charging system components: Correct charging behavior helps protect the alternator and electronic modules.
• Supports start‑stop performance: Ensures the system only stops the engine when the battery can reliably restart it.

Skipping registration can shorten battery life and create issues such as erratic start‑stop behavior, warning lights, or reduced comfort functions, so it is best handled by a shop with BMW‑capable diagnostic tools.

Practical Guidance for Replacing a BMW 320i Battery

When selecting a replacement battery, the goal is to match BMW’s original specifications as closely as possible while ensuring proper installation and coding.

Key Points to Consider When Buying a Replacement

Choosing the right battery for a 320i is about balancing size, capacity, and compatibility with the vehicle’s systems.

1. Match or stay close to the original Ah rating:
   

   • If the factory battery is 80 Ah AGM, choose another AGM close to 80 Ah (e.g., 80–90 Ah).
   • Avoid large jumps in capacity without confirming compatibility.

2. Stick with AGM if the car was equipped with AGM:
   

   • Start‑stop and energy management systems expect AGM behavior.
   • Switching to flooded can lead to shorter life and potential issues.

3. Confirm group size and terminal layout:
   

   • Most modern 320i models: Group 48 (H6) or Group 49 (H8).
   • Verify that polarity (left/right positive terminal) matches OEM.

4. Check venting requirements:
   

   • Trunk‑mounted batteries usually have a vent tube.
   • Ensure the new battery has the correct vent port and that the hose is connected.

5. Plan for coding/registration:
   

   • Have a BMW specialist or shop with an appropriate scan tool register the new battery.
   • DIY owners can use BMW‑specific diagnostic software and an OBD interface if experienced.

By confirming these points before purchasing, you reduce the risk of fitment problems, premature failure, or electrical glitches once the new battery is installed.

Summary

A BMW 320i typically uses a 12 V AGM battery in a mid‑ to large‑size group such as Group 47 (H5), Group 48 (H6), or Group 49 (H8), with common capacities between about 70 Ah and 95 Ah and CCA ratings around 720–850. Exact size and specification depend on the model year, generation, and equipment, especially the presence of start‑stop and advanced energy management.

For owners, the most reliable approach is to check the existing battery label, confirm the Ah rating and AGM type, match the physical group size, and then ensure the new battery is correctly registered in the car’s ECU. Following these steps keeps the 320i’s electrical system stable and maximizes the lifespan and performance of the replacement battery.

How much does it cost to replace the battery in a BMW 320i?

between $458 and $515
The average cost for a BMW 320i Battery Replacement is between $458 and $515.

What kind of battery does a 2014 BMW 320i take?

Duralast Platinum Group Size 49 H8 AGM Battery H8 AGM.

What kind of battery does a 2016 BMW 320i take?

Duralast Platinum Group Size 94R H7 Absorbed Glass Mat (AGM) Battery H7-AGM.

Which battery is used in the BMW 3 Series?

Suitable batteries for BMW 3 Series (Diesel) Passengers Vehicles

	AMARON PRO Automotive Battery – 600109087 (AAM-PR-600109087)
Series	Pro
Item Code	AAM-PR-600109087
Model	600109087
Product Dimensions (LxBxH) (mm)	353x175x190