> Have you ever seen or driven a car where, as you sped up, the lights got brighter? That's because the battery was dead and all the electrical power was coming

> Have you ever seen or driven a car where, as you sped up, the lights got brighter? That's because the battery was dead and all the electrical power was coming from the alternator with no battery to act as a load-balancer. Not in a long-long time. Voltage-regulated alternators have been a thing for decades now. By the 90s, most companies had solid state internal voltage regulators. Also, most (probably every) modern cars feed the alternator signal through the ECU/PCM before it gets to the battery specifically because it's crucial that computer-controlled component receive a clean, reliable voltage signal. I learned this the hard way.