1954 Royal Battery drain

I have a 1954 Royal that I just put back to a generator after someone monkeyed with the wiring and installed a12v battery and alternator. I got it all back to 6v and everything works great, except when turned off, the generator still receives power from the battery and begins to heat up. Is that a bad voltage regulator? Battery charges fine when running and everything works fine until shut car off. Battery drops immediately.

Any help, thoughts or suggestions would be appreciated.
Author: 1954Royal