No i have not changed anything on it, I still got the default mk5 golf head unit.
I am just wondering how would you know if the alternator went, that could be a possibility. As the car batterry does fill up takes a while. Then you can drive the car, but if you turn it of and leave it for 2 minutes then the battery is dead again.
Wouldnt think its a bad battery but may have to test that too.