I was thinking to power down the router and M1-XEP via the output relay, when I receive the low battery signal from the P1215 at 11V. I lose a bit of autonomy that way, but don't crash the router every time...
It would send the low voltage email, wait a minute and then shut down communication.
When AC Restore happens, I turn the router and M1-XEP back on.
It would send the low voltage email, wait a minute and then shut down communication.
When AC Restore happens, I turn the router and M1-XEP back on.