Most people have no idea how the charging system of a car works and they really don’t have to know. What you should know however is how to test to see what the problem may be.
Here is how the test goes if you how the charging system of a car works and you left the lights on is one thing. On the other hand if you did not leave lights on and come out to a dead battery then you need to get a jumper box or cables and get a boost.
Once the car is running disconnect the positive cable from the battery, this cable should most of the time be red in color and be a wider then the negative cable. When you remove the positive cable and the car runs for more then two minutes, that means that the battery is the problem for sure.
The reason for that is the car only needs the battery to start the engine in motion, then the alternator will take over recharge the battery and supply the car for the rest of the time it is running. If you take the positive cable off and the car cuts right off the the alternator needs to be replace. You can get brand new or used batteries and alternators at your local auto salvage yard or give Vinny at New York City Auto Salvage a call at 718-297-9797