I think around 13.3 or so after sitting for 12hrs. With a 160 amp alt, my driving voltage stays right at around 14.3-5, and I did a 10 minute demo this past weekend at DB drag finals, playing it full tilt, the LOWEST I saw was 11.9 on a sick low note, thats with 2 ss 6500's and a 10.0 on the highs