to push a 8.1 you are going to need more than one alt and two batts to push the system and its not recommended to use the 12v post on those batts but it can be done if you really want to do 16v i would get two 16v alts that can charge 19.8v or 19.4 i forget what it is to charge a 16v battery and pick up four+ 16v kinetiks and not use the 12v side as much as possible i know the car will use the 12v but dont run a bunch of acceries(sp) at one time but the ideal thing to do would be to get two alts one 12v for the car and one 16v for your batts and system i hope this helps a little