Reply To: Link 3 values in blender that aren’t normally linked

To give an example of how this could be done with Drivers (wouldn’t call it beginner-friendly):

The Total (400 Watt) is ‘hard coded’ here, but it wouldn’t be difficult to add another Custom Property for that.

If you want to play around, here’s a link to the .blend:

https://drive.google.com/file/d/1NUkACNcy7hqo3zrcWHiuMveTPHpriEX3/view?usp=sharing