Car battery dies overnight without a light and or started

What is your question?

My car battery is 2 months old and it has died on me twice now. It will die overnight or after a full day of not using it. I charged with a battery charger and it said it was at 80 percent when I stopped and the next morning it was completely dead. My friend said it might be a bad grounder but it just dies so quickly. It's a 1.8t.

What makes this problem better or worse?

It's worse when I don't use it for a day

How long has your 2001 Volkswagen Golf had this problem?

A month