I need to know if I need a new battery or alternator.I have a ford taurus 2005. When I started my car this morning on the way to work the lights were dim and windows went down real slow. 4 min. Later the headlights and interior lights went out and ten minutes later while at a red light the engine died and would not turn over. Someone stopped and gave me a jump long enough to start but it died out within a minute. I moved my car to a safe spot and left it. Later I returned and someone gave my battery about a fifteen minute jump. It started and I got my car to my job now. I left it for about an hour or so and went out and it started no problem.I havent moved it yet because im not sure if it will make it home because I dont know if its the battery or alternator
The battery could be getting weak but it's not the cause of the current problem. The generator keeps it charged up while driving and it supplies the current for the car's electrical system. The dim lights and slow windows were the clues that there was a problem. That gave you the warning time to get safely off the road.
If you charge the battery at a slow rate for an hour, you should be able to drive up to half an hour if you don't turn on the lights or heater fan. Have the charging system tested. Often the voltage regulator / brush assembly is all that fails, and used to be pretty easy to replace, but Ford has also had a design problem that makes replacement of the generator a better choice.