How do you charge the phone? You only get a few hours to use a phone in this manner.
Plug the charger into the victim’s house! DUH
Pretty sure you just hide and wait for someone to come and retrieve it.
Power bricks are relatively cheap. Also the video camera may not be running continuously. Maybe an app is only taking a picture every few minutes, etc..
I don’t know. But if I ever need to covertly surveil someone and do the
research to find out, I’ll let you know.