@Withered1 

I just got the same camera and am having the identical issue. I asked Technical Support and got the standard boilerplate response of check connections, etc.

Since the battery remains fully charged for two days, it would appear that the problem is in the app. It seems the Beta Solar Charging Data is not working as it should. 

  @JEP1950 I also installed my Tapo C425 three days ago, with its solar panel.  The connections seem to be fine, as far as I can tell, and the app shows that the battery is 100% full and has been the entire time, which leads me to believe that everything is actually working fine.  However, Solar Charging Data (Beta) claims there is no power supply, and suggests I should check if the panel gets enough sunshine (it does, the entire day) and if the panel is properly connected (I checked, it is, and how else would the battery be 100% full after three days?).  So, I also think there is something wrong with the app software, indeed.