Q: Power intermittently goes on/off, shutting down everything. 2004 Saturn Vue

Starting about a month ago, we believed my car battery would just die on us randomly. It would not be every time, but on occasion (it may be an hour or a few days between driving) I would try to start the car and nothing. No clicking, no lights, no sounds, no power. Jump starting it worked every time. We replaced the battery, it did not fix it. We tested the alternator, came back good. Replaced the battery again with no changes.

Then things got worse. The issue was so intermittent I can not drive anywhere. I was backing the car up after getting everything tested and out of now where the car turned off like you unplugged the battery. 2 sec later the lights came on and was able to start.

We tested the connections to the battery (positive, negative, and ground) and all are in great order with no corrosion. It almost seems like there is a wire or something not connected to the battery that moves, which would explain why it is intermittent. Thanks so much!

My car has 280000 miles.
My car has a manual transmission.