During the 6-volt era, automotive engineers went to great lengths to avoid imposing loads on the system. My dad has informed me that windshield wipers used to be powered by manifold vacuum, and that when you accelerated to pass, your wipers would stop!

The early Volkswagens had an even more questionable power source for the wipers: the spare tire. There was an air line running from the trunk to the wipers. Better hope you don't have a flat during a rainstorm!

So many other accessories we take for granted now did not exist then, such as power windows. Water and fuel pumps were engine-driven. Air conditioning was also non-existent, except on the most expensive cars.

Also, remember that many pre-war cars had two headlamps and one taillamp, period. No turn signals.

Then, those of us who came of age in the '80s or later (myself included) might have a hard time imagining just how unreliable cars used to be. Before the advent of solid-state rectifiers in the early '60s, the charging system consisted of a DC generator with brushes which would burn out at the worst possible time. To have an early warning of this, you needed an ammeter on the dash, which carried the entire charging current. If the ammeter failed, it opened the circuit, and the car would grind to a halt.

I've also read someplace that the current practice of running the voltage regulator at about 14V dates from the '80s, when engineers were trying to find a way to accommodate ever-growing loads without an extremely expensive upgrade to a new battery voltage. I don't know what the charging voltage was before that.

I seem to recall reading around the turn of the millenium that within five years, all cars would have 42V electrical systems, with a DC/DC converter to supply lights, radio, etc. Anybody ever see one of these? Just imagine: electric A/C compressor! No more expensive refrigerant charges from leaky seals. You could have an electrically-driven camshaft, for infinitely-variable valve timing. I can't remember all the other advances that were supposed to result.

Is the future here yet?