Apple Watch series 4 & 7

Hi Vinny9890,

Thank you for participating in the Apple Support Communities. We understand your Apple Watch is having battery drain issues, and we'd like to assist. These articles have some information and tips that may help:

Batteries - Maximizing Performance

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There are a few ways you can preserve battery life on your Apple Watch:

• During running and walking workouts, turn on Power Saving Mode to disable the heart rate sensor. To do this, open the Apple Watch app on iPhone, go to My Watch > Workout, and turn on Power Saving Mode. Note that when the heart rate sensor is off, calorie burn calculations may not be as accurate.
• For longer workouts, you can choose to use a Bluetooth chest strap instead of the built-in heart rate sensor. To pair the Bluetooth chest strap with your watch, make sure the strap is in pairing mode, then open Settings on Apple Watch, select Bluetooth, and choose from the list of Health Devices.
• If you’re very active with your hands and your watch display turns on more than you think it should, you can prevent the display from turning on every time you raise your wrist. Open Settings on Apple Watch, select General, select Wake Screen, and turn Wake Screen on Wrist Raise off. When you want to turn on the display, just tap it or press the Digital Crown.
• Disabling Bluetooth on your iPhone increases the battery drain on your Apple Watch. For more power-efficient communication between the devices, keep Bluetooth enabled on iPhone.

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Apple Watch Battery and Performance

Take care.

If the battery drains too fast after an update, see all the replies to:

Battery Drain since watchos 7.4 - Apple Community

WatchOS 7.5 battery drain - Apple Community

FWIW, in some cases, unpairing the watch, completely erasing it, then pairing and restoring the backup will resolve the battery draining issue after an update. (Simply unpairing and pairing again may not work.)

Unpair and erase your Apple Watch - Apple Support

Also, some people have found that simply waiting a few days after an update resolves the battery draining problem.