The BATLOGGER WE X is a device that usually needs mains power and is meant for indoor use (not waterproof). If you know what a charge controller is and you don’t mind building stuff yourself, there’s still a possibility to use it oudoors.
You need these parts to make it work:
Make sure that the WE X is in a completely waterproof box and figure out a way to get the microphone cable outside of this box without letting water in.
The BATLOGGER WE X, the solar panel and the battery need to be connected through a charge controller: