Hi everyone,

I think i'm having a small electric issue, but i'm not sure how to check.
I'm looking for some experience, because i want to prevent the need for jump starting in the near future.

My 1 serie had a weak battery when i bought it: slow crank in the morning (not to be confused with LONG crank, it starts after the first or second revolution, just pretty slow).
When i replaced this battery (thinking it was old), i found out it was a - smaller than OEM capacity - battery that hadn't been registered in the past.

When i installed the new battery (and properly registering it like you should), the problem slowly came back: slow start in the morning, but it did start every time.
The voltage that the MHD app shows me is around 11.3 - 11.6 volts, but the car does start.
When i check the battery itself with a meter (engine off), the voltage slowly drops from 12.7 v to around 12 v and sometimes a bit lower.
Isn't this kinda low for a brand new battery and isn't something draining it (IBS maybe)?

Charging volts are around 14.8 - 15 v at idle.

Is there something i could check before throwing parts at it(voltage regulator, IBS)?
I have a feeling some harm was done in the past when the car was used by the previous owner (years of running with an unregistered battery) and a part of the electrical system is damaged now (due to under/overcharging maybe).
It's a stretch, but definitely possible.