How does an alternator work and I have a 93 F150 truck with a new battery and I know the alternator is bad would this cause the truck not to start at all even with a new battery?
Even a new battery cannot start and run the vehicle for long without the charge it needs from the alternator. The battery has a certain amount of reserve power meant to start the vehicle only, then the power supplied by the alternator keeps a constant flow of power going to the battery to keep it charged enough to run the electrical system of the car. The electrical system, especially in late model vehicles pulls a large amount of electricity, so without that constant flow to replace the high draw, the battery is drained of its reserve. If you have driven the vehicle with a malfunctioning alternator, then parked it, chances are there is just not enough power to turn the vehicle over and start it again, as it has been drained completly.If you charged the battery on a charger, it would,(if a bad alternator is your problem)start and run the vehicle again, but just until the battery is drained.