I'm completely familiar with Ohms Law. I wouldn't say twice if I were you. It's not that linear due to resistance in the wire. A system still only draws as much amperage as is needed for the circuit load no matter what the voltage is. The wire size depends on more than one factor.
I use this Advisory Circular chapter 11 for conductor wire and fuse sizes when I have to fabricate or modify an electrical system. Using the charts are easier than doing the calculations to find out what size wire I need.
https://www.faa.gov/regulations_poli...cumentID/99861