I have tested how the UPS HAT cycle works. And it works exactly as is expected: when there is no power, UPS HAT powers the Raspeberry (I have a Raspberry 3), until the battery reaches 20% of charge, and then it begins a safe shutdown.
But I have reviewed the logs, and 5 seconds after the shudown finishes, it seems that the raspberry restarts again, It loads everything up, and about 30 seconds later the Raspberry shutdowns again. This time not gracefully, it seems like if the UPS HAT cuts the power at that moment.
I copy here the lines in syslog:
… (Here the Raspberry is shuting down)
May 6 12:52:33 a1bp systemd[1]: Stopped target Login Prompts.
May 6 12:52:33 a1bp rngd[276]: stats: entropy added to kernel pool: 2178432
May 6 12:52:33 a1bp rngd[276]: stats: FIPS 140-2 successes: 111
May 6 12:52:33 a1bp rngd[276]: stats: FIPS 140-2 failures: 0
May 6 12:52:33 a1bp rngd[276]: stats: FIPS 140-2(2001-10-10) Monobit: 0
May 6 12:52:33 a1bp systemd[1]: Stopping Getty on tty6…
May 6 12:52:33 a1bp rngd[276]: stats: FIPS 140-2(2001-10-10) Poker: 0
May 6 12:52:33 a1bp rngd[276]: stats: FIPS 140-2(2001-10-10) Runs: 0
May 6 12:52:33 a1bp rngd[276]: stats: FIPS 140-2(2001-10-10) Long run: 0
May 6 12:52:33 a1bp rngd[276]: stats: FIPS 140-2(2001-10-10) Continuous run: 0
May 6 12:52:33 a1bp systemd[1]: Stopping System Logging Service…
May 6 12:52:38 a1bp systemd-modules-load[102]: Inserted module ‘i2c_dev’
May 6 12:52:38 a1bp kernel: [ 0.000000] Booting Linux on physical CPU 0x0
… (here the Raspberry is initializing)
…
May 6 12:53:04 a1bp systemd[1]: pms_agent.service: Service RestartSec=3s expired, scheduling restart.
May 6 12:53:04 a1bp systemd[1]: pms_agent.service: Scheduled restart job, restart counter is at 3.
May 6 12:53:04 a1bp systemd[1]: Stopped Sixfab PMS Agent.
May 6 12:53:04 a1bp systemd[1]: Started Sixfab PMS Agent.
May 6 12:53:07 a1bp systemd[1]: systemd-fsckd.service: Succeeded.
- It seems that here the UPS HATS cuts the power.
- After several minutes I pluged again the power to the UPS hat and when the battery reached 25 % of charged the Raspebrry initialized again, this time with no more issues.
May 6 13:20:39 a1bp systemd-timesyncd[248]: Synchronized to time server for the first time 185.132.136.116:123 (2.debian.pool.ntp.org).
May 6 13:20:39 a1bp systemd[1]: Starting Clean php session files…