Battery details for the Pixel Watch have leaked, as have the smartwatch's connectivity options. While the Pixel Watch may have a larger battery than the 40 mm and 42 mm versions of the Galaxy Watch4 series, it will only match the Fossil Gen 6 in terms of battery capacity.
https://www.notebookcheck.net/Google-Pixel-Watch-battery-capacity-and-connectivity-options-surface.617226.0.html