The revolution of smartphones have changed the dynamics of human life. With the continuous development in the smartphone’s technology, one expects to perform most of the tasks with the help of smartphone. Eventually, it is becoming possible to perform most routine jobs through a smartphone like paying utility bills, managing excel sheets, streaming online movies and tons of other tasks as well. On the other side, the smartphone needs a stable power to stay alive. A smartphone without a steady battery is quite useless. But due to stiff competition among the smartphone producers, they are bound to provide slim mobiles, which lessens the chance of bigger batteries. Also, most of the smartphones are relying on, decade old, lithium-Ion battery technology. All above factors point towards the importance of batteries and their low capability. But one has to understand first that a smartphone battery does not drain automatically unless it is faulty one. Here we will try to discover those factors which kill battery fast in idle mode.