Hi guys , I know I'll get blasted for going to an 8 volt battery, but hey it starts like a brand new car.. I was worried about the  6 volt radio ( bone stock 55 country sedan ) so I wired in a 15 amp capacity buck converter  and adjusted the output down to 6.2 volts to the radio , seems to work as expected.  But the i got thinking (dangerous ) why cant I wire it into the yellow wire at the solenoid since it seems to be the main if not only  power feed off the battery , effectively controlling the feed to everything to 6.2 volts ?  I'd be interested in your thoughts... Thanks Fred