On Sun, 12 Feb 2017 09:27:40 -0600, philo wrote:

First off, you need to find a mechanic that knows how to actually check
your electrical system rather than just blindly throw parts at it. You
probably did not need an alternator or battery. That said, if your
battery was over five years old, replacing it was probably not a bad
precaution.

With the engine running, check the battery voltage , it should be
approx. 13.8 volts plus or minus .2 volts is normal


If that is OK then obviously something is draining the battery
overnight. Since you would probably notice a light on, it might be the
trunk light...I'd check the trunk light switch first then go from there.

_How To Perform a Parasitic Draw Test - EricTheCarGuy _

https://www.youtube.com/watch?v=KF1gijj03_0

I have seen an instance in an older car where the brake pedal
depressed just a bit, not enough the light the brake lights, but the
pedal switch was causing the drain.... FWIW.