Dear crotchety old rocket scientist,
An automotive alternator produces AC voltage (DUH! thats why they’re called ALTERNATORS!) and then at the voltage regulator a diode blocks half the AC leaving behind the DC our cars electronics operate on ... Maybe you’re stuck in 1964 and believe cars still have DC generators like my Corvair did... trust me they don’t.
Go back to designing your solid state coolers (note I’m not stuck in 1964 I didn’t call them Ice Chests) for truckers... looking back at your posts all I see are snide comments and put downs over minor wording issues.
Are you sure that the electric system doesn’t use some variant of a full-wave bridge rectifier? It would seem quite silly to only use a half-wave rectifier. With a full-wave rectifier your loss is limited to the voltage drop of the rectifier diodes, not “half the AC.”
Tore apart many Corvairs to make nice beach buggy's. The 140hp version was my favorite.