This vehicle has a new battery, the alternator is charging properly. There are no problems if the vehicle is used on a daily basis. However, if the vehicle sits for 2 days, the battery will be dead.
What could be pulling down the battery.
The usual procedure is to hook up a current measuring meter and start pulling fuses to find what circuit is drawing the most current. Then hunt it down from there. Note: you may want to have the set for a few hours as it appears some problem children don’t cause a problem right away.
The auto parts store has amp gages for the dash. Get one for this test: Disconnect the negative battery cable. Connect, or just touch, the gauge posts to the negative battery post and the battery negative terminal (series). Watch the amp gage as someone pulls the fuses one by one. When the amp gauge makes a drop, that circuit which that fuse powers has something which is still drawing power. Then you check that circuit, and it’s components, to find which, and why.