Car Battery keeps dying

in my experience its usualy a short some where. or if your car has a security system it could be faulty,

I occasionally had to jump my car. One of the times we jumped it we noticed the bolt was a bit loose. OPnce we tightened the bolt, the battery was fine. Since your battery was just replaced perhaps the bolt was not tighttened enough?

I've worked with NAPA for some time and we get a lot of customers in who have the same problem, sometimes it's just because the battery is no good. At times like this we recommend getting a new battery. It can be the wiring as well or even your Alternator going bad, I recommend getting both your Alternator and battery checked to see if one of them is causing your problem. It can even be as simple as needing a charge, if the battery has sat for a while, especially on concrete, the charge might have been drained out.

The above answer is good but they left out check EVERY connection from battery to starter, alternator and ground. It could be a tight connection but the cable may be worn to only a couple of strands still making connection.