The day before yesterday, my normal driving (for the most part lol) car was parked, went into store, came back out 5 minutes later got a click when I tried to start the car. Attempted to jump the car, nothing. Took the battery had it tested, guy said battery was good. Next day put said battery back in after getting it towed home; AAA knocked on starter car came on.. Replaced starter. Drove car for 15 minutes maybe car slows down despite pedal being on the floor.. Windows won't work battery is drained. Replaced battery. Drove fine 15 20 minutes and the same thing! What is this? when AAA was here the guy said the alternator tested good... Please help!

 

What is the voltage on the battery when charging?
If your alternator is indeed good, the voltage on the battery should be 14.1-14.5 Volts when charging.
If not, the alternator is bad or the connectors need cleaning.

 

if the battery is draining with a brand new battery that means that the alternator is not keeping it charged, so bad alternator most likely, or loose cable, drive belt ect, most likey alternator if everything else is good.

 

Probably a loose or corroded ground

 

this is the best advise.