Energy Ring - Battery Indicator Energy Ring app more than anything understands that you need to utilize your battery efficiently. Energy Ring sits on the screen silently putting almost 0% load on CPU, if battery level changes, Android wakes up Energy Ring. Once awake, Energy Ring quickly updates itself and goes back to sleep. And to be that extra efficient, the Ring goes on deep sleep when you turn off the screen, meaning it doesn't even read changes in battery level when the screen is off. An