Car batteries, those lead-acid beauties, are 12-volt and have been for my entire life. They changed from 6-volt during the first half-century of car design, as engines got more complicated and batteries got better; the higher voltage allowed various improvements, including thinner wires.
Now Delphi, the leading car-accessory firm, is pushing a 48-volt (!) system to power a “micro hybrid” electric engine that would assist during some acceleration but not much more. Wards Auto reports: “Delphi says such systems will deliver 70% of a mild hybrid’s fuel-economy advantage at 30% of the cost, expected at about $1,000 to the OEMs. About a 15% fuel-economy improvement is expected beyond the 15% that comes from downsizing to a gasoline direct-injected engine with turbocharging and variable valve timing.”
Remember when choices over car engines were pretty simple? Turbo or not and how big (diesel/gas was never a big deal here) – that’s all you needed to decide. These days the choices just keep growing. It’s just like light bulbs, which used to be grab-and-go … now I spend 10 minutes starting at the racks of displays.