[Ghettobird52]

Hey all! Hope October is off to a great start for everyone. I recently replaced my battery and went with the Duralast Platinum H6 AGM 70ah 760CCA 950CA. An H6 was in the car when I bought it. After I replaced it, I went to code it through Bimmercode and recognized the registered value was 90ah (H8). I went ahead and coded it to 70 ah AGM, and registered it through Bimmerlink. Fired her up and had a great drive with it! All is well.

However, I'm thinking about the 90ah original setting. Obviously the p/o replaced the wrong battery at some point. The battery stamp was 03/19 and I've owned it for the past two years. Other than the battery dying out recently, there hasn't been any issues with the battery, other than an occasional battery warning if I play with electronics after the car is off for a little bit. I never really thought about it but curious now if those two things were connected.

My question is, would you stick with the H6 AGM or return the battery (if possible) and get an H8 (or H7)? Any thoughts or advice is appreciated! Thanks everyone.

[3PedalJake]

Registering the battery main purpose is to efficiently charge the battery, IMO entirely possible having incorrect charging rates could have contributed to a early death, tho 5 years isn't extremely short in battery years. IMO the H6 is fine in sunny warm CA, and I'm sure you use it regularly. If you left it parked for days in Alaska I'd go for the H8.

[lowrydr310]

If you already have a relatively new battery leave it be and code it properly. When it is time to replace it again, replace it with the H8 and code for the H8. Bigger is always better even in good weather.

My 335 just had the original battery replaced last year, H8 AGM. 16 years and 160K miles on the original battery, BMWs intelligent charging profiles and location of the battery away from the engine compartment are doing something right.

[StradaRedlands]

I recently did two batteries, dropped a H7 in the 330i and I squeezed an H8 into the E91... definitely a bit of a hassle, but that car had CIC & bluetooth, etc, so I figured more potential battery draw. The 330i is pretty minimal electronically other than heated seats.
If you can swap out for no charge, I'd say exchange for the H8, just know it's a hassle to install.

[POBEP]

my 2c+

IF you plan to keep car for a while AND your wallet allows
THEN get quality AGM H8
ELSE what you have should keep you going for at least 4 years

My story
- 2009 E91 factory non-AGM H7 lasted for 10y, replaced with quality H7 AGM
- 2013 E70 35d factory AGM (105AH) still going strong
- 2016 F25 28d factory AGM (105AH) still going strong but has hidden code - battery aged and needs replacement
- 2011 E90 335d - previous owner mentioned he was replacing using cheap NAPA H6 non-AGM every 2 years. last one died at 2Y mark sharp. After quality H8 AGM replacement no more starting issues.

[Ghettobird52]

Thanks everyone for your thoughts! I went ahead and swapped it out for the Duralast Platinum H8 900CCA 1000CA 95AH. And boy StradaRedlands you weren't messing around when you said it was a hassle to get in! I had all the wires tied back/up as best as I could and I still had to massage that thing down into its new home! I went ahead and coded/registered it, however in BimmerCode I noticed it only has '90ah AGM' as an option. I'm hoping this will won't affect the longevity of the battery itself. Anywho, thank you all again! I appreciate the time and help. Have a great weekend!

[StradaRedlands]

Yeah, some quality fun, huh! Better last a LOOOOOONG time!

90AH is the right way to code.