Recent fast battery degradation of 2017 i3 (94Ah) at 120k miles / 8 years

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Philipp

New member
Joined
Feb 17, 2023
Messages
4
Hi all,

I bought my 2017 i3 REX (94Ah) in 2021 when it had 103k miles. The battery condition was excellent.

I believe I got a Kappa Max of ~28.8 kWh in 2022 or 2023, at perhaps 110k miles. I remember it was higher than the capacity that BMW advertises. I didn't measure Kappa Max regularly.

Over the last few months, now at 120k miles, I started noticing that my range was decreasing quite a bit. My Bat Kappa Max is now showing as 24.4 quite consistently. Being in California's mild weather, it shouldn't be strongly affected by seasonality.

It seems that the battery had zero degradation for many years but is now falling of a cliff.

Is it worth getting it checked? Would that have to happen at a BMW dealer?

I checked the codes and there are 13 codes related to the Battery management system all saying "Test failed since last DTC clear".

I did hit the underbody of my car twice (once a rock, once a "freestanding" curb piece) which was scary but didn't seem to have immediate effects on the battery (it happened a few years ago).

Overall, is it worthwhile to investigate this? Is there something I can do at home prior to spending significant $$ at the dealer?

Thank you :)
 
Do you leave your car fully charged for any period of time or do you only leave it overnight when not fully charged?
If you do not leave it fully charged for any length of time, the automatic battery equalisation system does not get a chance to work and battery will degrade. You can fix it by regularly leaving the car overnight fully charged or charging and then fully charged
 
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