There are not many things to complain about the Samsung Galaxy S6, the improved design finally features a premium build, the display is sharp and crisp thanks to its AMOLED technology, the Exynos 7420 processor provides a solid performance overall and its camera is among the most powerful ones in any mobile device. Two features that got removed from last year's flagship for the first time were the expandable storage option and the removable battery, both of which were certainly missed by some users. While some rumors have mentioned that the Galaxy S7 could feature a microSD card slot, the battery probably won't be user-replaceable once again. The 2,550 mAh battery integrated into the Galaxy S6 wasn't able to provide the battery life users expected from such device, but a new rumor suggests that Samsung could improve this aspect in the Galaxy S7.
There have been many leaked spec sheets of the Galaxy S7 and most of them provide contradictory information, so we don't quite know what to expect from the upcoming flagship. The specs on one of the most recent leaks mention that the Galaxy S7 could integrate a 3,000 mAh battery, which should improve on battery life. Now, Eldar Murtazin who has provided some reliable information regarding upcoming devices in the past, has tweeted that the Galaxy S7 is capable of playing video for more than 17 hours while the screen is set at maximum brightness. He mentions that it is a record for devices in this class. There's no way of knowing how he got this information, so it might not be completely accurate. This could have been taken from Samsung's theoretical claim regarding battery life, which might differ from day to day usage. The Galaxy S6 is rated for 13 hours of video playback, so the new information doesn't sound impossible.
Of course, besides a larger battery and the screen brightness, there are more factors that intervene in battery life, such as efficiency of the processor and optimization of the software, so probably the company has figured out a way for this to happen. The Galaxy S7 should be unveiled around the MWC 2016, which is scheduled from February 22 to February 25, so we won't have to wait too long to confirm all of these rumors.