Project: 72 hours mobile film

Hello,
for a new project I want to make a mobile film with a duration of about 72 hours. I can’t find any mobile camera (GoPro etc.) that can film this long. I already looked for strong battery packs etc. but could only find camera with about 12 hours non-stop-filming power. Do any of you guys know a mobile camera that works with more than one battery and can film for 72 hours non-stop?
Thing is, the camera is “alone” and I cannot interfere whatsoever during the filming. It really must film 72 hours straight…
Greetz
Answer #1
Security type cam + network server.