The main suggestion I would have in regards to using the battery as a UPS:
If you want the battery to last a long time, you need to figure out how long it takes for it to charge and discharge, and set up an outlet timer (either a manual one or a zigbee operated one) so that the outlet the phone is plugged into turns on just long enough for the battery to charge, and then turns off just long enough for it to discharge, with the aim to keep it in the 30% to 80% charged range.
Otherwise you’re just always charging the battery and significantly reducing it’s life and ability to be a UPS.
I just use these, I have a few old phones set up as a surveillance system. I’ve never tried an external ethernet dongle because unless you search for a special connector cable, you can’t charge the phone and have it plugged into ethernet at the same time.
If you’re selfhosting stuff, you easily host Home Assistant, install the app on the phone, and use the battery sensor from the app to turn on and off a smart plug.
The main suggestion I would have in regards to using the battery as a UPS:
If you want the battery to last a long time, you need to figure out how long it takes for it to charge and discharge, and set up an outlet timer (either a manual one or a zigbee operated one) so that the outlet the phone is plugged into turns on just long enough for the battery to charge, and then turns off just long enough for it to discharge, with the aim to keep it in the 30% to 80% charged range.
Otherwise you’re just always charging the battery and significantly reducing it’s life and ability to be a UPS.
https://www.amazon.com/Century-Indoor-24-Hour-Mechanical-Outlet/dp/B01LPSGBZS
I just use these, I have a few old phones set up as a surveillance system. I’ve never tried an external ethernet dongle because unless you search for a special connector cable, you can’t charge the phone and have it plugged into ethernet at the same time.
Oh yeah good point with the battery cycling.
If you’re selfhosting stuff, you easily host Home Assistant, install the app on the phone, and use the battery sensor from the app to turn on and off a smart plug.