My battery backup solution

[milandjurovic71]

This is what I use

https://www.amazon.com/dp/B07SFKYDNM/ref=cm_sw_r_em_apa_i_UHFdEb48VBV33
Last around 14 hrs unplugged. It stays plugged in all the time. In case of power outage, keeps recording.
There are many other similar products there.