[Eldorado]

I have the same problem.
I was against it being my battery compartment too, because it looked fine...
Because I was at my wits end, I plugged the drain hole in the battery compartment, removed the battery, and filled it up with water. I got in the car and sure enough, there was a steady dripping...

Try that...

Now, with that said, it could be leaking from your sunroof, but if that were the case chances are it'd land on the rear seat...

might be the seals around the door....

could even be windshield.

but I'm putting money on the battery tray.. mine looked to be in good shape too, but it still lets water go through...