What Kind of Battery Does a 2008 BMW 550i Take?

A 2008 BMW 550i typically uses an AGM (Absorbent Glass Mat) Group 49 (also known as H8 or L5) 12‑volt battery, usually around 90–95 Ah with a minimum of about 720–900 CCA, and it should be registered (and coded if type/Ah changes) to the car after installation. Below is a detailed breakdown of specifications, options, and what owners should know before replacing the battery.

Core Battery Specifications for the 2008 BMW 550i

The 2008 BMW 550i (E60 chassis, V8 engine) is designed to work with a high-capacity, trunk-mounted battery that supports a power-hungry electrical system and BMW’s intelligent charging strategy. Using the correct battery type, size, and rating is important to avoid electrical issues and premature battery wear.

Standard Battery Type and Size

The original equipment battery in most 2008 BMW 550i models is an AGM unit in the Group 49 size, sometimes labeled differently depending on brand and region.

The key physical and type specifications are:

• Battery type: AGM (Absorbent Glass Mat), maintenance-free
• Group size: Group 49 / H8 / L5 (these designations are largely interchangeable for fitment)
• Voltage: 12 V
• Location: Trunk (right side, under trim panel)
• Polarity: Standard left-positive configuration for Group 49 AGM units (always verify before purchase)

Together, these attributes ensure the battery fits the plastic tray and hold-down bracket in the trunk and connects correctly to the factory battery cables and venting system.

Performance Ratings (Ah, CCA, and Reserve)

Beyond the physical size, the 2008 BMW 550i requires a battery with sufficient capacity for its V8 engine and extensive electronics.

Typical performance specifications for a correct replacement battery are:

• Capacity (Ah): Approximately 90–95 Ah (amp-hours)
• Cold Cranking Amps (CCA): At least 720–900 CCA (many premium units fall in the 800–900 CCA range)
• Reserve Capacity (RC): Usually around 160–190 minutes (varies by manufacturer)
• BCI / EN ratings: May be listed as both CCA (BCI standard) and A (EN standard) depending on brand

These ratings ensure reliable cold starts, stable voltage for sensitive modules, and adequate reserve for periods of high electrical demand or short-trip driving.

AGM vs. Flooded: Why AGM Is Recommended

BMW engineers spec’d AGM for this generation of 5 Series because of how the battery is used and where it is located. Owners sometimes consider cheaper flooded (wet-cell) batteries, but understanding the differences is important before making that choice.

Advantages of AGM in a 2008 550i

AGM batteries are more expensive than conventional flooded batteries, but they are better suited to the 550i’s design and electronics.

Key advantages of using an AGM battery include:

• Better deep-cycle tolerance: AGM handles frequent partial discharge and recharge better, which matches BMW’s intelligent alternator strategy.
• Lower self-discharge: AGM loses charge more slowly when the car sits, important for vehicles that aren’t driven daily.
• Spill-proof construction: Safer in a trunk installation, especially in the event of a collision or tipping.
• Improved vibration resistance: Beneficial for preserving battery life in a performance-oriented sedan.
• Compatibility with IBS system: The Intelligent Battery Sensor (IBS) and charging logic are tuned with AGM behavior in mind on many 5 Series of this era.

Taken together, these traits help extend battery life and maintain stable electrical performance, particularly for a car with many control modules and convenience features.

Can You Use a Conventional Flooded Battery?

Some parts catalogs list both AGM and flooded Group 49 batteries for the 2008 550i, and some owners do run conventional batteries. However, doing so has trade-offs.

If considering a flooded battery, keep the following in mind:

• Coding/registration change: If the car is coded for an AGM battery and you install a flooded unit, the charging strategy will be wrong unless updated with a scan tool.
• Shorter life expectancy: Flooded batteries typically don’t last as long under BMW’s charging regime and heavy electrical loads.
• Ventilation requirement: You must connect the vent tube properly; gasses released into the trunk can cause corrosion and odor.
• Warranty and dealer support: Dealers and some independent shops may insist on AGM to match OE specs.

While a flooded battery of the correct size and rating can work, AGM remains the safer and more OEM-consistent choice for a 2008 BMW 550i.

Fitment Details: Group 49 / H8 / L5 Explained

Battery sizing designations can be confusing, especially when cross-shopping different brands and standards. The 2008 550i’s tray and hold-downs are designed around a long, large-capacity European-style case.

Group 49, H8, and L5 Equivalents

Depending on where you buy your battery, it may be advertised under different codes that refer to roughly the same size.

Common size designations that should fit the 2008 550i include:

• BCI Group 49: North American standard size used by many major auto parts retailers
• H8: Common European-style designation (often used by AGM manufacturers)
• L5: Another European size code, usually equivalent to Group 49/H8 in dimensions
• DIN/EN codes: Some batteries will also list DIN or EN size numbers, but Group 49/H8 is the easiest cross-reference in the U.S.

These labels all point to a long, relatively tall battery case that matches the factory tray and clamp, avoiding issues with loose mounting or cable reach.

Physical Dimensions to Check

Even within a group size, small dimensional differences can exist, so a quick measurement check is wise if you’re buying online or using a non-automotive brand.

Approximate Group 49/H8 dimensions are:

• Length: About 15 inches (≈ 394 mm)
• Width: About 6.9–7.0 inches (≈ 175–177 mm)
• Height: About 7.5–7.6 inches (≈ 190–192 mm)
• Weight: Typically 55–65 lbs (25–30 kg), depending on brand and construction

Confirming these measurements against your existing battery or owner’s manual helps ensure a proper fit, especially if the car has been modified or previously fitted with a non-standard unit.

Battery Brands and Example Part Numbers

Several high-quality aftermarket brands produce AGM Group 49 batteries suitable for the 2008 BMW 550i. Availability and part numbers can vary by region, but many options are widely sold by auto parts chains and online retailers.

Common Aftermarket AGM Options

While you should always verify fitment with a current catalog, the following are typical examples of batteries that often fit a 2008 550i’s requirements.

Representative AGM battery options include:

• BMW Genuine Battery: OE AGM Group 49/H8 (sold through dealers; part numbers can vary by market and supersession)
• Exide / Varta: AGM units often labeled as H8/L5, commonly used as OE on many European cars
• Interstate: AGM Group 49; often sold under part codes like MTP‑49/H8 (verify AGM vs flooded)
• East Penn / Deka (also rebranded as Duracell in some chains): Group 49 AGM offerings compatible with BMW fitment
• Auto parts store house brands: Many major U.S. chains sell a “Platinum AGM” or similar-branded Group 49 battery that meets the 550i’s specifications

Specific SKU names vary, but any quality AGM Group 49 with at least ~90 Ah and 720+ CCA, and correct venting capability, is generally suitable when paired with proper coding/registration.

Battery Registration and Coding: A Critical Step

Unlike older cars, the 2008 BMW 550i’s charging system is managed by software. Installing a new battery is not just a mechanical job; it requires informing the car’s control module that a new battery is in place.

Why Registration Matters

BMW’s Intelligent Battery Sensor (IBS) and engine control module track battery age and condition, adjusting alternator output over time. If you simply drop in a new battery without updating the system, it will treat the new battery like the old, worn one.

Key points about battery registration include:

• Resets learned history: Tells the car that a fresh battery is installed, so it can adjust charging accordingly.
• Prevents overcharging/undercharging: Correct charging profile extends the life of the new battery.
• Avoids electrical anomalies: Improperly registered batteries can contribute to warning lights, accessory malfunctions, or early failure.
• Required with any new battery: Even if you replace with the same type and capacity, registration is still recommended.

Registration is usually done with a BMW-compatible scan tool—at a dealership, an independent BMW specialist, or with owner tools like ISTA, INPA, or certain aftermarket diagnostic devices.

When Coding (Not Just Registration) Is Needed

Beyond registration, coding is necessary if you change the battery type (AGM vs flooded) or significantly change the capacity (Ah rating).

Coding considerations include:

• Changing AGM ↔ flooded: The charging algorithm must be updated to match the new chemistry.
• Significant Ah change: If you move from, say, an 80 Ah unit to a 95 Ah unit (or vice versa), coding the new capacity ensures proper charging behavior.
• Done with advanced tools: Coding often requires higher-level diagnostic software or a specialist; not all generic readers can do it.
• Best practice: Match the OEM specification and then only perform registration; this simplifies the process.

Many owners choose to stay with an AGM battery of similar capacity to the factory unit, which limits the task to registration only, avoiding the need for more complex coding changes.

Practical Tips for 2008 BMW 550i Battery Replacement

Because the battery is in the trunk and tied into multiple systems, replacing it on a 2008 550i involves more than just swapping parts. Taking a few precautions helps prevent damage and data loss.

Before Removing the Old Battery

Preparation can reduce the chance of faults and make the swap smoother.

Helpful steps before removal include:

• Maintain power if needed: Some owners use a memory saver to preserve radio presets and window settings, though it’s not strictly required.
• Turn off all electronics: Key out of the ignition, lights off, doors closed where possible.
• Document existing battery: Note the type (AGM vs flooded), Ah rating, and label information for reference.
• Access area carefully: Remove trunk floor and side panel trim to expose the battery and mounting hardware.

Spending a few extra minutes on these steps can prevent unnecessary diagnostic work later and ensure you select the right replacement.

During and After Installation

The physical swap is straightforward but involves handling a heavy component and reconnecting sensitive electronics.

Key practices during and post-installation include:

• Disconnect negative first, reconnect last: This reduces the risk of short circuits.
• Secure the battery firmly: Use the correct hold-down bracket so the battery cannot move under braking or cornering.
• Reconnect the vent tube: Ensure the vent line is attached to the new battery’s vent port to route gases outside the vehicle.
• Register (and code if needed): Use a capable scan tool to inform the car of the new battery and its specifications.

Once registered and fully secured, you can test-start the vehicle, check for warning lights, and verify that electronics and charging voltage behave normally.

Summary

The 2008 BMW 550i is engineered to use a high-capacity AGM Group 49 (H8/L5) 12‑volt battery, typically in the 90–95 Ah range with robust CCA and reserve capacity. While some owners install conventional flooded batteries, AGM is the most appropriate and OEM-aligned choice, especially given the car’s intelligent charging system and trunk-mounted battery location. Proper fitment (Group 49/H8/L5 dimensions, correct polarity, venting) and, critically, post-install registration—and, when chemistry or capacity change, coding—are essential to ensure reliable operation and long battery life. By matching these specifications and following best practices during replacement, 550i owners can maintain the electrical stability and performance their V8 luxury sedan was designed to deliver.

What size battery is in the 2008 BMW 550i?

Duralast Group Size 49 H8 Battery H8-DL.

What size battery is in the 2008 BMW 535xi?

The 2008 BMW 535xi battery size is typically a Group 48 (H6) or 94R (H7), though some sources also mention Group 49 (H8) or 95R as potential fits. It is important to verify the correct size by checking the battery currently in your vehicle and ensuring the new battery has the appropriate cold cranking amps (CCA) and reserve capacity. 
Common battery sizes

• Group 48 (H6): A common and often correct fit for the 2008 535xi. 
• Group 94R (H7): Another frequently recommended size that is compatible with the vehicle. 
• Group 49 (H8): Some retailers list this as an option for the 2008 535xi. 
• Group 95R: Mentioned as another compatible size, though some sources suggest potential fitment issues or the need for a specific type. 

Important considerations

• Verify your current battery: The most reliable way to ensure the correct size is to check the label on the battery currently installed in your car. 
• Check CCA: Make sure the new battery meets or exceeds your vehicle’s original cold cranking amps (CCA) specifications. 
• Reset vehicle computer: Some modern BMWs require the vehicle’s computer to be reset by a service specialist after a battery replacement to ensure proper function. 

How much does it cost to replace a BMW 550i battery?

Labor costs are estimated between $106 and $155 while parts are priced between $295 and $334. This range does not include taxes and fees, and does not factor in your unique location.

What type of battery does my BMW use?

Most modern BMWs use an AGM (Absorbent Glass Mat) battery, especially those with start-stop systems, but the specific type depends on the model and year. Electric and hybrid BMWs use different batteries, primarily lithium-ion for the main power and sometimes NiMH (Nickel-Metal Hydride) for hybrids, with a traditional lead-acid battery often serving as a supplemental power source. To find the exact battery for your car, check the vehicle’s owner’s manual or look for the model number and specifications on the battery itself. 
For internal combustion engine (ICE) BMWs

• AGM (Absorbent Glass Mat): The most common type for modern BMWs, especially those with advanced electronics and start-stop technology, according to this BMW article and Every Battery.
• EFB (Enhanced Flooded Battery): An upgraded version of a standard lead-acid battery that can be found in some models, as detailed by Every Battery.
• Traditional flooded lead-acid: Older BMW models may have a standard lead-acid battery, but these are less common in recent years due to the increased electrical demands, notes Every Battery. 

For electric and hybrid BMWs

• Lithium-ion: The most common type for electric vehicles like the i4 and iX, according to Athens BMW. These have a high energy density and efficiency. 
• NiMH (Nickel-Metal Hydride): Typically used in hybrid vehicles, explains Athens BMW. 
• Supplemental lead-acid: A traditional lead-acid battery is often used as a secondary battery to power the vehicle’s 12-volt electrical system, according to Athens BMW. 

How to find the right battery for your car

• Check your owner’s manual: This is the most reliable way to find the exact specifications for your vehicle. 
• Inspect the battery: The old battery will have a label with its specifications, such as group size (e.g., Group 49, H8) and CCA (Cold Cranking Amps), notes AutoZone.com and getBMWparts.com. 
• Use online tools: Many auto parts websites have tools that let you input your BMW’s year, make, and model to find compatible batteries, such as AutoZone.com. 
• Contact the dealership: The BMW dealership can confirm the correct battery part number for your car.