I had this weird problem today.

I drove about 5 miles this morning and parked the car. Everything was working fine. After about 15 minutes I went back to the car and I had very little battery power. Dashboard would barely light-up.
I jumped the battery and started the car. It was idleing very intermittently and throttle had no response at all. I could not get the car moving. I had ton leave the car at that car park. What can this be?

My car is a 2001 A4 1.8t. I had an alternator recently replaced, battery was checked and was working fine before this incident. Although there was no throttle power after I started, the voltometer was up to 14v as usual and there were no warning lights on the dashboard.

Thanks

 

Anyone at all?