how do i get my voltage up a little

[doubleD]

i have a 240 amp alt just for my subs and sub amps,,there are two V-MAX charge tank batteries back there with the amps,,,just driving around town my voltage hangs around 13.6 to 13.7.....down the highway it gets to 14v...how do i get the voltage closer to 15v or to hang around 14.7

[Spitfire2k6]

whats the rating of your batteries and your alt? if your alt is only a 14V you wont get higher if im not mistaken

[k3n12ock]

15v? Gotta up to 16Vs.

[rubbernutz1]

i believe ud have to have an external voltage regulator for you alt.