Ok..in a nutshell.....2000 I30 battery keeps dying (Optima Yellow Top *brand new*). Just replaced my starter 2 weeks ago. Got the car to turn over last night with cables, unhooked the battery (to see if the car would cut) and it kept running strong...so i'm thinking its not the alternator. Anyone have any ideas? Thanks in advance.

 

there's really nothing left, but the alternator. do you have a multimeter?
if so check the voltage of the battery with the car off. if it reads 12v the battery is good. now crank the car. at idle you should be getting 14V, or at least 13+. if you're still getting 12v or less then it's the alternator. if you're getting the 13+ it's not the alternator and since you've replaced everything else it can't be the charging system period.
If you don't have a multimeter you can pick one up and walmart for $20.
If you don't have $20 or a way to get to walmart I would consider stopping by with my multimeter depending on what side of Atlanta you live on.

 

if u tap the multimeter on the optima, a charged yellowtop will display 13+ volts. Its a deep cycle. You unhooked the batt and car kept running means its still charging. Try reving it and see if it cuts while ur not on the batt. If it cuts ur alt isnt giving a charge strong enough to charge the batt

 

Thanks for the input guys! I figured it out...I had a completely corroded baterry terminal So I changed it out and the car turned right over. Now i feel like an idiot lol. Thanks again for the responses!