Battery Deka or OEM Subaru

In sum, I can fully recommend the Deka ETX30L battery for long-term and continuous use in our cars.

I have some extended experience with a lightweight battery in my daily driven 2006 Boxster S, which is well known for the demands it places on the battery. In spite of that, I successfully used the Deka ETX30L (21 lbs.) for almost 3.5 years.

EDIT: Confirmed fitment (duh) and ordered the Deka through Batteries Plus. This battery seems to be best fit as its reserve capacity is nearly double that of the Optimas.

I have had excellent results from a Deka Intimidator 9A48 High Performance AGM Battery Deka / Remy part # 9AGM48 installed Dec 2010

I don't recommend anything less than the DEKA ETX-20L for a car that see true street duties. The ETX-14 is 200 CCA @ 12 lbs, and the 4 lbs weight loss isn't worth it for 70 CCA loss on a small battery in charge of starting a car. The ETX-18L does 270 CCA @ 16 lbs and much more suitable for our 4 banger application. The ETX-18 however is the one I recommend to 95% of readers of this thread. It cranks out 300 CCA at 18 lbs, which is still plenty light.

I've always had sucess with the Deka ETX-20L in the DSMs, two EVOs, a Saturn race car, and now the TT (most of them running on E85 which is hard to start on cold winter mornings). As long as you discipline yourself to not run accessories with the engine off, they are a great option!

I had an Optima 5 or 6 years ago but I heard the quality has went down and the warranty isn't as good as it used to be. I picked up a Deka intimidator deep cycle battery and It's by far the best battery I've owned.

The OEM battery sucks I upgraded mine to an AGM with an extra 100 or so CCA. A better battery will also let your auto start stop last longer. Stock battery would never last a stop light for while under load new battery gives me a lot more time even under load.

My battery keeps dying if I dont use my car for 1-2 days and Subaru is failing to address the issues.

Subaru has had a problem with their electrical systems since 2014. Batteries last 2 years, max. 2018 legacy is on its third battery in 4 years. 13,000 miles. $600.00 in batteries.