Battery drains when not running

You have an electrical draw on your charging system somewhere. Sounds like your ALTERNATOR isn't keeping your system charged buy a multimeter and check your voltage with car running and accessories on should be between 12-14 volts if not your ALTERNATOR is most likely the issue. Good luck

Probably a "leaky diode" in the alternator is draining the battery. Test that first by disconnecting the alternator to see if the problem stops.

To find what's draining the battery, when the car is parked, disconnect the negative battery terminal and hook up a test light between the negative battery post and the negative battery cable. If it lights up, you have something drawing current, that shouldn't be. Start pulling fuses, one at a time, until the light goes out. That will tell you which circuit is the culprit. From there, look at what item, or items are tied to that fuse and then you'll know what to disconnect to confirm (by the light finally going out). I hope this helps