Q: Will a bad alternator cause my vehicle not to start at all

If the battery is good and the alternator stops charging. The car will be able to run on battery power for several hours and restart a few times before the voltage gets too low to keep things working. Usually you will see a warning light when the charging stops, but not always. If the battery is dead replacing the alternator will not make the car start. And the car needs to be running and the battery fully charged in order to test the alternator. don’t recommend trying to jump start the car. I have fielded too many questions from people who have done serious damage to their cars by making a small mistake. Charging or replacing the battery is what is in order. I like to use a motorcycle battery charger to slow charge the battery overnight. If you have to move faster than that, you can replace the battery. Contact YourMechanic to have a technician come out to your home or office to replace you battery right there on the spot.