87 4cyl battery drain issue
 

I have something draining the charge on my battery I cannot figure out. I charge the battery to 12.7 with the cables disconnected. When I connect the battery cables to the battery it drains the battery overnight. Initially when I connect the cables I see the voltage drop from 12.7 to 12.5, then slowly goes down from there to completely dead within 24-36 hours. I have removed all the fuses from the fuse panel in the dash and the voltage still drops. I have replaced the positive and negative battery cables as well as the starter solenoid. What I read on line says it could be a bad ground but where? When I installed the new negative cable it is connected to the battery and then to the engine block in the same location as the original cable. The negative ground from the terminal the engine frame by the solenoid is also there and looks fine. All the connections look clean and are not corroded. Any suggestions? Thanks.