Convert RGB to HSV 3 bytes

Question

Hey guys, So I have been messing arround with color spaces and while I have got code that will allow me to convert a RGB value to a HSV ranges 350, 100, 100
However I have seen that openCV and apparently googles color picker converts it to ranges that are compatible to bytes, 180, 255, 255.

I have been searching and experimenting in vain to try and recreate the method openCV is using.
If anyone has any idea how to do the conversion from RGB to HSV 180,255,255 and back to RGB 255,255,255, I would really appreciate it :)

Thanks guys!