E36 Battery Mount for Optima 35 RedTop and D35 YellowTop

Your standard lead acid battery can leak acid and form rust in your battery compartment. This silently happened to our E36 before we could even notice there was an issue. Even with an acid-neutralizing mat under our OEM battery, we still fell victim to battery acid ruining our battery compartment. 

Optima solves this issue with absorbed glass mat (AGM) batteries that don't leak. There is a RedTop variant for general use, and a YellowTop that can withstand deep cycling. What deep cycling durability means is that Optima YellowTop batteries can be revived from low charge more times than a typical lead acid battery. Low charge will damage typical lead acid batteries and greatly shorten their lifespans. YellowTops are robust batteries that can bounce back after your battery loses charge, whether it's from a failed alternator or from leaving your headlights on accidentally. They are also great for cars that are parked for long periods of time without access to a battery maintainer. Recharge the YellowTop, and it's likely good to go again.

The only problem with Optima batteries is that they don't make a direct-fit battery for the E36, so their batteries can't be mounted using the factory battery mounting system. Our mounting tray allows Optima 35 RedTop and YellowTop D35 size batteries to be mounted in your E36. There is enough room to retain the plastic factory battery cover as well for a clean OEM look.

We created a weight-optimized design, making it as light as possible and only as heavy as necessary. Using thoughtful part geometry, we were able to create a lightweight and cost-effective solution. We looked for weight savings anywhere we could, utilizing lightweight polypropylene strapping with a mini cam-lock to secure the battery over heavier metal tie-down hardware. Borrowing on our aerospace experience, we used sheet aluminum and aircraft rivet construction to minimize weight over a machined part. We even took the time to create a dimpled lightening hole in the mounting bracket. The result is an assembly that weighs a feathery 18 ounces (514 g).

The Optima batteries are sold separately and can be purchased on Amazon here by following these links: Red Top, Yellow Top.*

Fits all E36 models with trunk-mounted batteries.

*As an Amazon Associate, we earn from qualifying purchases.