The alternator is not working properly. Your car will still run off the battery for a little while then when the battery dies the car dies. Check the alternator or take it to autozone and they will check it for you.
It could be your connection to your battery. If its bumped loose, you would lose all power, even while driving.
A Twin Turbo Mustang would be used for driving. It could be used for racing most likely as well, but the use of a car is quiet obviously driving places.
Could be many reasons such as bad alternator, or bad fuel pump.
Usually when the battery light comes on its the Alternator, or a bad wire from Alternator to battery, but id check Alternator first.
your Alternator
I am not completely sure on why you battery in your Mustang would be smoking only when connected to the starter. I would take into a shop and have them look at it.
Bad battery or alternator, or simply ran out of gas
the ground to the battery i had the same problem on my truck
It mostly is your neutral safety switch i had the same problem good luck
If the alternator fails, it is no longer keeping the battery charged and your engine is running on nothing but battery power. Once the battery runs down, your engine will no longer run.
If its totally dead (no radio, no starter) I would first look at your alternator/battery. This happened to my 2003 Trailblazer, and we had to replace the serpentine belt and the alternator. Battery light came on while driving and within ten minutes, the car was dead.
If you lost power while driving and it did not start again, it could be an alternator issue. Double check the battery just to make certain it isn't an issue with the cable connectors too.