SSD Booting : low power issue

[HeviiSailor]

I wired it this way because I was worried about something happening and Pi staying on and draining the battery while my boat is on the mooring.  It has been 2 years of use now and it has never took more than 15 sec to power off, so I might swap it to be truly constant (unless the master battery switch is off).  I have never had a corrupted SD card with this system.  Before this it happened frequently.

I appreciate the time that you've taken to explain this, Jason. It's ïnspired me to dig deeper into the rabbit hole of safe RPi shutdowns.