You have an excessive amount of current draw through the regulator assembly inside the alternator. Most of them are made offshore these days, and they're junk. Normally, it's only a few milliamps, and it would take weeks to drain the battery. Either install an original equipment Delco Remy regulator (NOT AC-Delco) or wire the excitation voltage through he ignition switch.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!