Ignition wirng harness

If it sits for long periods with any draw on the battery, or if the starter turns a lot before it fires and runs the charging system would show higher during recharge. My 67 sits for weeks with the battery connected sometimes. Stereo memory the only draw ( not much ). If its going to sit for months I disconnect the battery. I always do spin it a bit before I move the throttle, set the choke, let is start and run. So the gauge shows higher output for a short time. It always recovers the battery and drops to normal operation though.