Audi A8 Battery Fitment

Audi has been producing variations of their popular A8 sedan in the North American market since 1997 and they have used a variety of batteries over the years. That's to be expected though, in a car that has offered diesel, gas and hybrid options over four generations, with engines varying from 2.8-liter V6s up to massive 6.0-liter V12s. Even looking at the battery fitment chart for the Audi A8 over just the last 20 years can be a bit of an eye chart, so we'll help you in a couple of ways.

First, we'll explain the relationship between DIN and BCI battery sizes, because there are equivalent sizes that you'll see in the A8 fitment chart you see below. While the fitment chart only shows the BCI group sizes, we'll translate that into DIN battery sizes and explain the OPTIMA's DH6 YELLOWTOP is the same size as an H6 or Group 48 battery and our DH7 YELLOWTOP is the same size as an H7 or Group 94R battery. Our friends at Weistec Engineering also offer adapter hold-downs, which allow Audi A8 owners to run a lighter DH6 YELLOWTOP in either H7 or H8 applications.

Now that we've deciphered the battery sizes for you, we'll dive into the actual fitment for the Audi A8. At the top of each page on this website, we have a battery finder, that will help you identify the options for your vehicles, if you enter your vehicle's year, make, model and engine size. While the chart below does not include fitment for the first generation of Audi A8s, our battery finder does.

The first column of this chart shows the production year and engine size. The second column includes footnotes, many of which are common throughout the years and we'll explain them here:

54- The battery is vented to the outside of the vehicle. Many batteries are located inside vehicles, either in the trunk or interior. In these instances, batteries have an external vent port that can be connected to a hose that leads to the outside atmosphere. In the unlikely event any lead-acid battery is severely-overcharged, the fumes it vents can be both toxic and flammable, so if your battery is located inside your Audi A8, make sure it is properly-vented to the outside atmosphere.

57- Audi used more than one battery size for this vehicle. In a post-COVID area, we're all painfully aware of the supply chain challenges the world faces. In some instances, an auto manufacturer may choose to install a different battery size than they normally would, based on availability. In those instances, they probably wouldn't install a lesser battery, but more likely a larger battery than what the vehicle needs, that is more readily-available at the time of production. If you choose to run a lighter OPTIMA DH6 YELLOWTOP in place of a battery that was either an H7 or H8, you'll need to make sure it is securely-mounted in the vehicle.

67- The A8's computer system must be reset and the battery registered with the Audi's charging system with a scan tool. This is becoming more common on newer vehicles, especially those with sophisticated electrical systems and significant electrical demands. As a battery ages, internal resistance can increase, which can reduce cranking ability and reserve capacity. It can also make it more difficult to recharge the battery. Newer vehicle charging systems compensate for this as the battery ages, so it's important to let those systems know when you've installed a new battery, so the charging systems charge it like a new battery. Dealerships and other service centers can perform this service for you

69- AGM Valve Regulated Lead Acid (VRLA) battery is required. All OPTIMA Batteries are AGM batteries, as opposed to flooded lead-acid batteries, where you can hear the electrolyte sloshing around inside the battery. This is a common requirement for many newer vehicles, especially those that use Start/Stop systems that require thousands of additional starting cycles from batteries.

70- PR Codes denote factory-installed options for this vehicle and Audi gives a production code for each piece of equipment installed on your A8. These codes are listed next to the engine in the chart above and can typically be found in both the spare tire well on the floor of your A8 or on the first page of the owner's manual. For instance, J2D is typically associated with H6 batteries, 0K1 with H7 batteries, J0B or J1U with H8 batteries and J0P or J0Z with H9 batteries.

Some A8s can use more than one size battery and since the dimensions of H6, H7, H8 and H9 batteries are identical, except for the length, any A8 that fits an H9 battery can probably also accommodate any of the three smaller sizes, although they should all be properly-secured.

The fifth column that shows numbers indicates Audi's requirements for Amp-hours (Ah). So what happened to the cold cranking amp (CCA) specification we've been trained to look for in car batteries? In the case of an Audi A8, even the smallest H6 batteries will typically have no trouble starting the biggest engines or even highest-compression diesel engines. The more important specification for modern vehicles is Amp-hours, because that identifies the amount of energy contained in the battery- the bigger the number, the more energy is available.

This is important in modern vehicles, because many of them use a significant amount of electricity, even when the car isn't running, including Audi A8s. If you only drive you A8 a few times a week, you'll want to not only make sure you meet or exceed that OE requirment for Amp-hours, but that you also periodically top off the charge on your battery with a quality battery charger. The reason is that the charging systems in vehicles that see infrequent use or frequent short trips, may not have enough time to properly-maintain voltage in a battery.

Fully-charged, our YELLOWTOP batteries, including our DH6 & DH7 batteries will measure about 13.0-13.2 volts. Whenever any lead-acid battery is discharged below 12.4 volts and is left sitting in that state, sulfation begins to form in the battery, which diminishes both battery capacity and lifespan. That makes a quality battery charger an excellent investment for any car owner. We're so confident it will extend the lifespan of your OPTIMA battery, we'll extend the free replacement warranty on your OPTIMA battery by a full year, if you purchase it from us at the same time as purchasing an OPTIMA Digital 1200 battery charger.

The final column explains the technology of battery that Audi installed in your A8 at the factory, between AGM (absorbed glass mat) and EFB (enhance flooded battery) lead-acid batteries. This is primarily in the newest hybrid models that offer Start/Stop technology and these are mostly H6 (Group 48) batteries. In these applications, an OPTIMA DH6 YELLOWTOP is a very suitable upgrade.