Finding a short that runs down your battery
With SOME cars.............
loosen and lift the battery ground cable, if it sparks, remove the clock
fuse, (under the dash) that is all that should be powered.
If the cable sparks again when touched to the battery terminal, something else is using power. Pull the fuse to interior lights.
If the cable sparks again when touched to the battery terminal, something else is using power. Pull another fuse and repeat 2nd paragraph, until the cable no longer sparks.............and then you will have found what is drawing current from the battery.
Let me know what that something is.-Bob