I tested the WyzeCam v2 with the latest firmware with a fully charged (first cycle) Anker PowerCore 10000. Lasted almost 22 hours (21:50 to be exact)!
7.63 GB were used during this test.
Motion detection was enabled and constant recording to SD.
I placed both the camera and battery in a closed cardboard box with several holes in the back for ventilation, and a big hole for the camera lens in the front.
The magnet on the bottom of the camera magnets to the battery (although not too strong).
No overheating was caused.
This is one of the smallest power banks of that capacity as of today, and it’s not too expensive ~ 30$.
Size: 92 × 60 × 22 mm / 3.6 × 2.4 × 0.9 in
Screenshots of the camera on top of the battery attached.