Rapid battery drain on 2023 C45

[mlm.sail]

Experiencing rapid service voltage drain. The batteries and the alternator are band new. The charger appears to be charging normally. Even with all breakers off the service voltage drops from 13.2 to 11.5 V in a matter of hours.

[JEN-et-ROSS]

Hi...
Sounds like a bit of a nightmare..
  Try fully charging the battery bank and then disconnect at the the battery bank..Not at the breakers..
The voltage will initially be quite high,13.5-14.5v but should settle to about 12,6v or so after a few hours...
If no further drop is observed then something is amiss in the yachts systems, possibly between the bank and the breakers..
If the voltage drop still occurs, then there's a problem in the bank or one of the batteries........Good luck....Bill.

[Odysseus]

Agree all above, probably one battery has lost a plate which would account for the 11.5v senario.