[Redd]

I recently had my battery replaced with a Banner 92Ah AGM battery. Banner are a BMW OEM supplier. Then I had the battery registered at a BMW specialist.

Here's the issue - Before I had my batt replaced, my voltage reading was a consistent 13.5 - 13.6V under all conditions. After the battery swap, it's been reading between 11.8V - 12.5V, even at higher rpms. Only occasionally it will go up to 13.5V. There are zero errors. I thought the new batt was poorly coded, so I had it registered a 2nd time, and also did an energy diagnosis for good measure. Alternator is working fine and charging the batt. I also have a CTEK Battery Sense and it shows that the batt is charging.

Are voltage in the 11.8V - 12.5V normal? Do new batts read less voltage? The alternator is only 37k kms old so I don't think it's due for replacement yet. Am I being overly worried?