We smartphone users could have experienced the following situation somehow. Theoretically, only in standby mode can an Android phone battery run for three days or even less. But frequent usage always places the battery in danger. Sometimes we even find the power to be low just a few hours after charging. However, phone calls and messages keep coming one by one, looking so important, and forcing us to get it done. But what if there is no charger or socket around? It’s not always a charge box offered when you’re walking. To make things worse, the battery capacity seems to…