2013 BMW 328i Battery

As vehicles offer more features, the electrical systems to support those features become more complex. That is certainly the case for newer BMWs, including the 2013 BMW 328i. One look in a fitment guide can be confusing for any BMW 328i owner- does my BMW take an H6, H7 or H8 battery? There are often multiple factors and accompanying footnotes that can determine what size battery is needed.

The best course of action is go to the battery in your 2013 328i right now and take a look. To find it, you'll need to open your trunk and pop off a panel on the passenger side of the trunk. There you should see the battery tucked into the bottom of the trunk. Hopefully, the label for an H6 battery will indicate that size or possibly a "Group 48" designation. The H7 is also referred to as a 94R and the H8 is synonymous with a Group 49 battery. 

So why three different size batteries for one single model year BMW 328i? As we mentioned before, complex electrical systems often require more energy to power new features. One of the most-demanding features is start/stop technology, where the engine turns off when the vehicle comes to a complete stop at a stoplight and automatically starts up again, when the accelerator is pressed. 

Start-stop technology requires a battery to start an engine thousands of times more than a traditional engine over the life of the battery, which can be very demanding on a battery and may require a physically larger battery. In order from smallest to largest, the H6 is smallest, followed by the H7 and H8. OPTIMA Batteries offers direct-fit replacement batteries for the H6 and H7 and many folks will find their rating for cold cranking amps (800 & 880, respectively) are well beyond the rating for the battery they are replacing and the same is true for their reserve capacity rating.

Some folks using their BMW 328i in high-performance applications may try to run the lightest battery they can and if the choice comes down to the H6, H7 or H8, the H6 is probably the winner. Weistec Engineering offers a bracket adaptor that will allow you to use an H6 in an H7 tray or an H6 in an H8 tray.

If running the lightest battery possible isn't a concern, check out the weight of the OPTIMA H6 & H7 batteries compared to the competition. You'll find they tend to be heavier by at least a few pounds. There are a couple reasons for that. First, we use all the space available inside the battery. We also use 99.99% pure virgin lead and we also use thick, cast straps to connect our cells, instead of weaker, cheaper tombstone welds. All of those features can add weight to a battery, but they can also increase cranking power, reserve capacity and lifespan. 

Once your battery is installed, you will need to register it with the vehicle's charging system. Your BMW dealership can perform this service for you, but dealerships are often not the most cost-effective option. Easy-to-use scan tools are available to do this as well and many folks find the price of a replacement battery and a scan tool is still significantly less than what their dealership might charge. Since these batteries are mounted in an enclosed area (trunk), you'll also want to ensure the vent tube is connected to the battery. In the unlikely event the battery is severely-overcharged, it could vent fumes that are both toxic and flammable and you don't want those sticking around inside your BMW.

Finally, we'll remind you that modern vehicles can be very demanding on batteries, even when driven on a regular basis. We recommend keeping your battery fully-charged (at least 13.0V for OPTIMA H6 & H7 batteries) whenever possible and topping off your battery once a month, just to make sure the battery isn't getting slowly discharged over time. We're so confident regular use of a battery charger will improve the performance and increase the lifespan of your BMW's battery, we'll add one year of free replacement warranty coverage to your OPTIMA battery, if you purchase it from us, along with a OPTIMA Digital 1200 battery charger.