An alternator is your car's power plant. While the battery starts the engine, the alternator generates electricity to run everything else—headlights, infotainment system, air conditioning—and, most critically, it recharges the battery while the engine is running. It converts mechanical energy from the engine's crankshaft into electrical energy through electromagnetic induction. If your alternator fails, the vehicle will eventually drain the battery completely and stall.
A healthy alternator typically outputs between 13.5 and 14.5 volts to properly charge the 12-volt battery. When it begins to fail, you'll notice signs like dimming headlights, a flickering battery warning light on the dashboard, strange whining or grinding noises, or electrical accessories malfunctioning. Unlike a simple repair, alternator issues often require a full replacement, which can be a significant expense.
| Common Alternator Performance Indicators & Data | |
|---|
| Normal Output Voltage | 13.5 - 14.5 volts |
| Typical Amperage Range | 65 - 150 amps (varies by vehicle electrical demand) |
| Average Lifespan | 7 - 10 years or 80,000 - 150,000 miles |
| Common Failure Symptom | Battery warning light illuminated |
| Replacement Cost (Parts & Labor) | $400 - $1,000 |
| Key Component | Internal voltage regulator |
| Critical Function | Powers all electronics while driving |
Regular maintenance, like ensuring the drive belt is in good condition, can help extend its life. If you suspect an issue, have it tested at an auto parts store or by a mechanic to confirm the diagnosis before replacing it.
