Must have a drain on the battery somewhere. Been to 3 auto stores 2 mechanics replaced battery twice .Still, within 2 weeks it's dead.Alternator is good also.

 

Jumping at this can get one into deep problems since there are so many possibilities.
Could you please tell us, if you know, what tests were done and what the results were.
Somebody must have checked alternator output, we hope, and didn't go any further. Is this one of the tests done?
As you know by this time , some auto stores don't want to get too involved other than to do a few checks .
The 2 mechanics , not wanting to get to the root of the problem may have reasons of their own.
Can you tell us right off if you have any aftermarket add ons ? Thanks.