Why does my RPi reboot when I restart my external power source?

@saeed or @ensar

I just bought the UPS from y’all. The battery is from y’all too. It works great on battery power alone. It works fine with the RPi external power (I have an official power supply from them). If I turn off my power supply, it works just fine on battery power…

Here’s the issue: if I turn off my external power and then turn it back on → my RPi now immediately reboots!

What is that?! How do I fix it?

Thanks in advance.

Do you turn off the battery switch too when you turn off the external power?

Make sure the Battery is fully charged.
Did you check the system logs, what made the RPi reboot?

Battery is at 100%

I have reproduced the same immediate hard reboots when the external power source is off and then:

  • I turn on the USB-C in line switch
  • I plug the external power source in without the in line switch attached

It is literally whenever power is “restored”, then it hard reboots.

Nothing in syslog. You can clearly/visually see the UPS perform the hard reboot. When external power comes back on, the red LED light on the UPS powers down.