I dont like to see below 13.2 if at all possible,im at 14.5-6, and low notes hit around 13.4 lowest ive seen so far in that truck,i may invest in another agm battery,to see if i can get back up to 13.6 lowest,I have 2 agm batts under the hood, and a 255 amp alt already/0ga on all/Big 5 i call it