Battery problems Z28

Hi there, this is my first post!

I'm a proud owner of a Z28 2001. :)
Unfortunately I've a problem with the battery.
When I'm not able to drive the Camaro, after a week the battery is dead/empty (but not always?!).

I've changed the battery for a new one, but the problem remains.

I have some suspects, like the Alarm system, but before checking with an Ampere meter and removing fuses, maybe there are some suggestions.

Thanks,

Peter

Alternator?

A couple easy things to do - make sure the connector at the alternator is clean and tight, and with the car running check for about 14.5 volts across the battery terminals. Is the volt gauge reading normal? Lights constantly flickering at night?

"A HAPPY NEW YEAR"

I've checked the alternator.
The alternator works OK, the volt gauge reading is normal.

What is the typical power consumption in rest (key removed, doors closed, etc)?

Thanks,

Peter