One other interesting point ... I'm curious from those more knowledgable than I regarding 12v electricity if this supports the 'diagnosis'.
When I tried to start on Battery 1 this weekend, nothing. Tried numerous time and nothing. The oil pressure alarm was bright and clear, but not a budge out of the starter
. When I added Battery 2 to the mix, it fired right off.
Consistent with the 'voltage' theory?