This comes contrary to a multitude of rumors prior to Apple's event, which suggested that the major efficiency improvements of the S9 and A17 chips would bring battery life improvements. The approximate battery life of each of the new devices Apple unveiled today is as follows:
Apple Watch Series 9: 18 hours/36 hours in Low Power Mode Apple Watch Ultra 2: 36 hours/72 hours in Low Power Mode iPhone 15: 20 hours iPhone 15 Plus: 26 hours iPhone 15 Pro: 23 hours iPhone 15 Pro Max: 29 hoursThis is exactly the same as the Apple Watch Series 8, Apple Watch Ultra, iPhone 14, iPhone 14 Plus, iPhone 14 Pro Max, and iPhone 14 Pro Max. Of course, efficiency improvements may still result in slightly better real-world performance in Apple's latest models.