All these LED lights have one thing in common: batteries. It’s unavoidable.
A bit harsh to all the battery-free flashlights out there. They are crappier most of the time, but ain’t that even more geeky - winding up your own light 
I’m actually quite happy with one of those, can’t remember the model right now though…
https://www.google.com/search?btnG=1&pws=0&q=led+flashlight+no+batteries
Good post anyway