There is a world of difference between the battery life of the Apple Watch Ultra 2 and the Series 10. In simple terms, Apple rates the Series 10 at 18 hours whereas the Ultra 2 stands at a whopping 36 hours. All these facts however are in terms of numbers, but with average day to day usage which comprises; notifications, always-on display, GPS exercise tracking for 1 hour, and sleep tracking, the Series 10 will be able to go for around 1 and a half days. The Ultra 2, on the other hand, has approximately 3 days of battery life. In order to accomplish different tasks, both smart watches are also equipped with different low power modes, which would greatly impact battery life.