Generator, Alternator & Voltage Regulator
Most American cars switched from DC generators to AC alternators in the mid-1960s. Regulated voltage is measured at the battery with the engine at about 2,000 rpm.
| System | Regulated Voltage (warm, ~2,000 rpm) | Notes |
|---|---|---|
| 6V generator | 7.0–7.4 V | Most pre-1956 domestic; many positive ground |
| 12V generator | 13.8–14.8 V | Late-1950s to mid-1960s; weak at idle |
| 12V alternator | 13.8–14.5 V | Mid-1960s on; charges at idle |