Works well  one usability issue I nearly dumped it as useless  because the reading did not change sign when going from discharging to charging. Then I discovered it changes the colour of the lightning icon instead - not what an engineer like me would expect. Now I know that I'm happy  and can find the optimum position on my various wireless chargers. I am marking it down one star because of that. Even changing the colour of the numbers would be better; Red for discharging and green for charging. Nexus 4  Kit Kat.
December 20 2014