Ultimate Lightweight Battery Guide

Weight reduction is a constant quest for those who track their cars and battery weight savings can be huge. Not only do lighter batteries save weight, but it can last longer as well. When shopping for a new lightweight battery, you’re going to have a lot of research to do. This Ultimate Lightweight Battery Guide is meant to assist your research to find what the best battery is for you. While taking a look at this guide, you’ll want to pay attention to the following variables: weight, technology, price and CCA.

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Battery Weight

The OEM BMW Battery (Exide) weighs 45.5 pounds! As we explained earlier, a lighter battery means a lighter car which means potentially a faster car. You want something as light as possible, however as the lighter the battery gets, the lower the CCA gets. What’s a CCA?

Cold Cranking Amps (CCA)

This is the measurement of amps a battery can deliver at 0F for 30 seconds without dropping below 7.2 volts. This is the most important rating when choosing a battery because you want your car to start when you need it to. What’s the point of weight savings if your car can’t start on a cold morning track day? Another variable to consider is CA which is the amount of current a battery can provide at 32F or 0C. If you live in an area with warm climates, consider looking at CA. The OEM BMW Battery (Exide) has a CCA of 640.

Battery Technology: Flooded vs AGM

The OEM BMW Battery is a heavy wet cell (flooded) based battery on older lead acid battery technology. The new technology is called AGM and it stands for Absorbed Glass Mat. These are specialty batteries that usually cost more than twice as a premium wet cell. They store very well and do not tend to degrade as easily. They are generally the safest lead acid batteries you can buy. They also offer greater life span and greater cycle life than a wet cell battery. AGM allows the electrolytes between the plates to be in close proximity increasing the discharge and recharge efficiency. These are good for deep cycle and deliver best life performance if recharged before 50% discharge rate.

Battery Price

Lithium and carbon fiber batteries can go upwards of $1,000 easily, but is it worth it? We’re writing this guide in the shoes of your average HPDE go-er so we’re focusing on a < $300 range of products.

Lightweight Battery Options

We hand-picked the batteries below. A lot of E46 M3 owners go with the Deka EXT30L battery or the Odyssey PC680, however you will need to consider a trickle charger or a kill switch to keep the car firing every morning. If you have any other battery suggestions, we’d love to know and add to our list. Please drop a comment below and let us know what battery you’re running and your experience so far.