Why Is My Apple Watch Suddenly Running Out Of Battery. Tap on your Apple Watch at the top of the screen. You can also un-pair right on the Apple Watch.
Tap Unpair Your Apple Watch to confirm. Tap on your Apple Watch at the top of the screen. If the battery acts normally thats good.
Tap Battery Health then turn off Optimized Battery Charging.
The one other thing you can try is force restarting your Apple watch. Using your watch in an environment outside the defined limit can surely damage the battery. Apples tips for maximising battery life and battery lifespan on Apple Watch are detailed here. Tap Unpair Your Apple Watch to confirm.
