https://www.cnet.com/news/galaxy-s9-battery-life-isnt-as-good-as-we-had-hoped/

The main reason for that expectation is the Qualcomm Snapdragon 845 processor that lives inside the Galaxy S9 and S9 Plus phones in the US and other countries. Samsung equips the Galaxy phones in some regions with its house-made Exynos chip, but it's the Snapdragon 845 we tested most.

The Galaxy S9 and S9 Plus have the same battery size as last year's models.