there are some dual voltage batteries that will do 12vs on one side and 16vs on the other...so you can use part of it with stock electrical the other side with your stereo
for a battery to maintain charge on a daily driving viechle with no external usage of charging device other than alternator - standard "12volt" batterys apply as they need charging of 13.8 to 14.4 volts to keep enough "juice" flowing to them to recharge from starting the car and other electrical needs.
a battery with a 14 volt rating will need to charge at 15.5 to 16.5 volts to main tain proper charge levels. using a standard 14.4 volt charging alternator in your car to attempt to keep a 14v battery going will always end up not charging the system as its just not enough voltage to keep it topped off. you will end up with a battery at 60% or less charge this way.
even cooler are the 16v batterys that need charging voltage of 18 volts to keep maintained.
the problem is that your car electrical system is not designed to handle any more than 14.4 volts and will start acting silly at about 15.3/.5 volts. electrical sensors / o2 readings / map and all other engine managment systems are designed to run on a constant voltage type system that functions with in peramiters of 12v to 15v any above or below will cause all sorts of crazyness to happen...
so in a daily driver type viechle - its mostly recomended to just go with some good 12v batterys for your setup to avoid all the hassle
And that's why I said you ment 12v battery.. unless your planning on a huge 16v battery bank. Or running dual altanator..But them options will cost you in the thousands to do.