No, you should not drive a car with an overcharging alternator. It is a significant safety hazard that can cause extensive and expensive damage to your vehicle's electrical system. An alternator that is overcharging, meaning it's producing a voltage higher than the standard 13.5 to 14.5 volts, is essentially frying your car's electronics. Continuing to drive risks destroying the battery, blowing out headlights and other bulbs, and damaging sensitive computer modules that control everything from the engine to the infotainment screen.
The primary culprit is usually a faulty voltage regulator, which is the component that controls the alternator's output. When it fails, the alternator can push 15 volts or more into the system. The first sign is often a battery warning light on your dashboard, but a more reliable way to confirm the issue is with a multimeter. With the engine running, a reading across the battery terminals of over 15 volts clearly indicates an overcharging condition.
The potential damage escalates quickly. Here’s a breakdown of what can fail:
| Component at Risk | Symptom or Type of Damage | Typical Cost of Replacement (Parts & Labor) |
|---|
| Car Battery | Boils off electrolyte, warps plates, significantly shortens lifespan. | $200 - $450 |
| Headlights / Taillights | Bulbs blow out frequently, often in rapid succession. | $50 - $300 per set |
| ECU / PCM (Engine Computer) | Catastrophic failure leading to engine stalling or failure to start. | $800 - $1,500+ |
| Infotainment System | Screen flickering, audio failure, complete unit malfunction. | $500 - $2,000+ |
| Other Control Modules | Issues with power windows, ABS, airbag system errors. | $300 - $1,000 each |
The safest action is to stop driving immediately and have the car towed to a repair shop. The repair typically involves replacing the alternator or its internal voltage regulator. While costly, it is far cheaper than replacing a battery, an alternator, and your car's main computer.
