This USB C cable lets the Bear Sentry energizer draw 12V power from a power bank that is capable of Type-C 12V PD (power deliver), like the one available under More Good Kit.
Add a DC extension cable and you could power the fence from inside your tent where battery capacity may be less affected by cold weather.
USB C to DC 5.5mm x 2.1mm interface, 3A max output, 40cm length, 12g