Based on several graphs studying battery life and endurance of phones since 2011, it can be safely concluded that Sony is leading the market. The general extrapolation of the data shows that the average battery life is on the rise, a very welcome change at a time where battery life is one of the game-changing criteria while purchasing a new phone.
The surprising fact coming out of the graph is the Japanese manufacturer, Sony, starting at the bottom of the graph in 2011, and going on to make the phones with the best endurance among all the major players, including Samsung, LG, and Apple. Sony is the dissident - always striving to optimize their software and hardware to squeeze the last drop of juice out of the batteries, allowing about two days in a single charge with normal usage. And they have successfully improved one of the critical requirements of a phone, given the relatively small battery capacities they include in their phones. Samsung comes in at a close second position, also making huge leaps of improvement in battery life with their new mid-range and high-end handsets. LG also performs decently, making a significant improvement in its optimizations, and allowing higher endurance. The only disappointment comes from Apple, as the endurance per mAh is on a steady decline for the past four years. The iPhone 6 will only last about a day even though it has a larger battery capacity, a surprising fact given how critical battery life is to a user.
The study also takes into factor aspects like increasing battery capacity, which has a positive correlation to the average battery life of phones. This effectively means a higher capacity battery should ensure higher endurance, and the average capacity has seen a steady growth over the years. There is a negative correlation between battery life and screen size which is also on the increase, but it is being rendered insignificant to the positive effects of battery life. Other developing factors negatively affecting battery life would be the inclusion of 4G LTE which is accompanied by beefed up hardware, decreasing the battery life by a significant margin.