Battery OEM BMW or OEM Subaru

Yeah they use undersized batteries, but just buy a good one and that's the end of it. my 2019 Legacy had is original battery after 4 years when I traded it in.

Yes. Subaru batteries are hot garbage. Go third party all day. I stand by any AGM I can pick up at Autozone, since they stand behind the batteries they sell.

My dealer replaced the battery, updated the firmware and did a parasitic drain test.

For about a month I have owned a 2016 REx whose 60 Ah battery is supposed to get 72 miles. This week I fully charged it and have been commuting four four days without topping up. Today the REx kicked in with the trip meter at 73.3 miles. This was a mixture of city traffic jams and short bursts on the carriageway, mostly with the air con on and mostly in Comfort mode. So I'm pretty pleased.

So we bought a new 550CCA battery and installed it and it started right up. When I pulled the 18 month old OEM battery out, I was shocked at the CCA rating: 356. 356!!!! That's insane.

I am still on my original battery in my 2007 335i w/ 87k miles.

Any tips or advice before I fork out money for a new battery? I have some anxiety hoping its not the alternator dying, or less likely the starter. All things point to a slowly dying battery but I want a second opinion.

Subaru batteries aren't great in the cold either

My battery made for Subaru died on my 2017 Forester 2 weeks before the warranty ran out. SUBARU has their own problems with their batteries.

Subaru batteries suck