An alternator manages the supply of electricity in your vehicle. If your car suddenly stops running, the alternator may have gone bad. A faulty alternator will cut the power supply to vital car components, and you will notice the lights turning off in the dash or the engine abruptly losing power.
What would cause a car to just stop running while driving?
When there is something wrong with the alternator, the car runs off of the battery. The battery can only run for so long before it's completely drained. Malfunctioning ignition switch. This loss of power causes the engine of the car to die while driving.
How far can you drive without alternator?
If the alternator output was weak for a long time before it failed, the car may not go very far. If you have a fully charged high capacity battery, you could drive a hundred miles at least in the day-time, on the battery alone.
How do I test my alternator manually?