The Galaxy Note 9 is shaping up to have a better battery life than its predecessor, based solely on the 20% increase in mAh capacity, as well as the more frugal, second-gen 10nm chipset. Samsung still advertises it as an "all-day battery" phone, though, which is not what you'd expect from a 4000 mAh pack, but, hopefully, it means a day with heavy usage.