14v batteries is a 14v setup, not a 16v setup as been stated before.
I see that the OP isnt too familiar with these types of electrical systems.
Therefore, I highly recommend that he just stick to the standard 12v charging system. Using 3-4 batteries on his alternator will do him great things.
The added wattage from going to full 16v comes at the expense of reliability, ease of setup and service.
With 16v, you will get a bit more power from your amp, but honestly, you may never be able to tell unless you have an SPL meter.