My Mountaineer has 78000 miles and has electrical problem.

As I drove off the other day the radio did not work as well as indicater lights on center dash;I stopped, turned off engine then I restarted it and all worked ok.

Next day I drove 2 miles, stopped ,locked car and returned in 1 hour; When I tried to start the car the battery sounded weak, tried again battery weaker, third time everything was dead and crackling noise from center of the dash area (with key off) The noise stopped within 10 seconds. I left the car, locked the doors, and came back in 1/2 hr; it started fine with no detection of a weak battery. then raw gas smell. The information center had reset, like it had lost power . No reset button had been pushed.
Took to dealer and no clue;checked battery,load tested start wires,checked connections,advised Ford ;still no clue.

Cannot duplicate condition.

Help!!