[kaared]

I have just installed three battery-based cameras from Eufy and I'm very happy with the experience and performance:

https://eu.eufy.com/pages/security_forever_power?ref=navi

The cameras I have are charge and use, but should last about six months befire you need to charge again. We'll see. Mine are only active when I'm away and they sense activity so that should help.

They have cameras with solar panel and 4G. If they have an external battery I don't know.