I was driving and my '01 TT 225hp lost power. the dials on the dashpod all stopped, but the car was still on. tried revving into gear and then the car just died. Got a new alternator, drove a couple days fine. Low battery indicator light comes on. After driving a lil' bit more, same thing happens. Just bought a new battery at Wal-mart, and the Low battery indicator light came on still after taking off.

Tested the car by leaving it running with the negative unplugged to see how long it lasts, but only lasted 5 seconds. The alternator is not charging up the battery.

Any suggestions as to why it is not charging? can it be the belt?

 

If the belt is ok, hook up a volt meter to the battery when the engine is running, if its less than 13V the alternator isn't charging the battery. Since you already replaced it do a volt drop accross the main charger cable. How you do that is put either the + or - cable on the charge port on the alternator then the other lead on the + post on the battery. If its more than 1V replace the alternator cable.