Battery light I have a 2003 sonata recently the battery light will come on for about 5 minutes and then it will go out I'm not sure if its the battery or the altanator

TRY THIS:UNPLUG THE NEGATIVE CABLE AT THE BATTERY..
WAIT 5 MINUTES AND PLUG IT BACK..THEN SWITCH THE RADIO ON...ENJOY!

If the radio lights up. Reprogram radio due to power failure. Should find instructions in owners manual if it is a factory radio. Otherwise look on line for reprogram instructions.

The 2003 Sonata is equipped with a 'starter KILL' burglar alarm system with disables the starting system (using a N/C 'contacts' configuration instead of a N/O contacts configuration). N/C=Normally closed, and N/O=Normally open contacts. When the alarm goes off with a MY Sonata, the only way to DISARM it is with the key fob (remote) originally programmed for it (unless you purchase a new remote & have it programmed for the vehicle at an authorized Hyundai Service Department). NOTE: So long as the keyless entry & burglar alarm system is functioning/operating normally, the alarm will keep going off and the STARTER KILL function will still prevent you from starting the vehicle. One option is left without purchasing a new remote and having it programmed.
1. When the alarm goes off, get into the vehicle and insert the ignition key into the ignition.
2. Turn the key to the 'RUN' position (NOT the ACC position) and wait for the alarm to STOP (usually about 3 to 5 minutes).
3. The engine should then start using the ignition key.

If this procedure doesn't work, the problem will need further diagnosis by a qualified/certified Hyundai Service Technician.

Hope this helps

either that or the battery. Stop at Advance Auto Parts asap. They offer FREE battery and charging system testing.

may be a bad alt check voltage while running should be about 14 volts

Not the battery. Once the car is started, a bad battery will not cause it to stop running all of a sudden.
For engine to run you need - compression, air, fuel, spark.
Might want to check out your ignition coil for an intermittent condition - try replacing it.
And if it does not turn over(crank) check the wiring going to the starter motor,solenoid, for good connectivity. And make sure that your fuel pump is always getting power and pumping.

dear friend-you can try and disconnect the battery and leave for half an hour for ecu to reset,reconnect and check.

remove the battery negative cable for 5 min's, but if this is to pass smog they will fail it.

Sound like the vehicles ECU (electronic control unit) is acting up. All electronics are controled through this module as well as the features your car is programed with. Many manufacturers have different names for these modules but they all perform the same tasks. Your best bet is to bring it to a dealer where they can hook up a computer whith their diagnostic software in it to pinpoint the problem. All electronics in vehicles are controled by modules which are like mini computers.

whats your weather stripping look like? dry rot? smashed down? toren? or may be comming thru back window? hole in trunk? thats all i can think of. happy hunting.