16.5.1 is draining battery

Have you tried to backup and restore?

The links to do this appear below:

Link for how to Back up and Restore: Back up and restore your iPhone, iPad, or iPod touch to your Mac or to iCloud - Apple Support

Link for putting iPhone in DFU Mode: If you can't update or restore your iPhone or iPod touch - Apple Support

Note: The above material is not my work. Any credit should go to Michael Brooks1  who originally posted it here: Jun 27, 2023 8:55 AM in response to Jubalub. 

Please report back wether performing the above process made the battery drainage worse, fixed it, or if you noticed no change at all. 

The measure of battery health deterioration is subjective and can vary depending on individual usage patterns and not on iOS version updates. There is no universal standard to determine whether the battery health deterioration is normal or abnormal because it heavily relies on how the battery is used and maintained.

Protect & Prolong the Life of your iPhone's Battery:

1. About the battery usage on your iPhone, iPad, and iPod touch ...
2. Batteries - Maximising Performance - Apple (IN)
3. iPhone Battery and Performance

Try some of these options too.

To prolong the life of your iPhone battery, you can follow these tips and best practices:

To prolong the life of your iPhone battery, you can follow these tips and best practices:

1. Optimize Battery Charging: Enable the "Optimized Battery Charging" feature on your iPhone. It helps reduce the wear on the battery by slowing down the battery aging process. You can find this option in Settings > Battery > Battery Health. About Optimized Battery Charging on your iPhone - Apple Support (IN)
2. Avoid Extreme Temperatures: Extreme temperatures, both hot and cold, can negatively impact your battery life. Avoid exposing your iPhone to excessive heat or cold, such as leaving it in direct sunlight or in a freezing car.If your iPhone or iPad gets too hot or too cold – Apple Support (UK)
3. Use Original Chargers and Cables: Always use Apple's original chargers and cables or certified third-party accessories. Low-quality chargers or cables can damage the battery and reduce its lifespan. Identify counterfeit or uncertified Lightning connector accessories - Apple Support (IN)
4. Avoid Draining the Battery to Zero: Charge it whenever the charge becomes lower than 20%. The rest is up to you when to charge. how long to charge, how often to charge, which adapter to use starting from 5W to 140W USB-C Power Adapter etc.
5. Optimize Display Settings: Adjust your display settings to optimize battery life. Lower the screen brightness, enable auto-brightness, and use shorter screen timeout durations. Adjust the display and text size on iPhone - Apple Support (IN)
6. Minimize Background App Refresh: Limit the number of apps allowed to refresh in the background. Go to Settings > General > Background App Refresh and disable it for apps that don't require real-time updates. Switch apps on your iPhone, iPad, or iPod touch - Apple Support (IN)
7. Disable Push Email: Push email notifications can drain your battery quickly. Instead, set your email accounts to fetch data manually or at longer intervals. You can change this setting in Settings > Mail > Accounts > Fetch New Data.
8. Disable Unnecessary Notifications: Reduce the number of unnecessary notifications you receive. Go to Settings > Notifications and customize which apps can send you notifications.
9. Limit Location Services: Some apps use GPS and location services in the background, which can drain your battery. Go to Settings > Privacy > Location Services and disable location access for apps that don't require it.
10. Update iOS: Keep your iPhone's operating system up to date. Apple regularly releases updates that can include optimizations and improvements for battery life.
    1. Update Over-the-Air (OTA) —> Update your iPhone or iPad - Apple Support (IN)
    2. Update using iTunes/Finder —> Update your iPhone, iPad, or iPod touch - Apple Support (IN)
11. Enable Low Power Mode: When your battery is running low, enable Low Power Mode in Settings > Battery. It reduces power consumption by disabling non-essential features.
12. Avoid Battery Drain during Storage: If you need to store your iPhone for an extended period, make sure to charge it to around 50% first. This helps prevent the battery from draining completely, which can be harmful.
13. Disable Dynamic Backgrounds and Motion Effects: Dynamic backgrounds and motion effects use additional processing power and can impact battery life. Use a static wallpaper and disable parallax motion effects in Settings > Accessibility > Motion > Reduce Motion.
14. Limit Widgets: Widgets on the Today View can consume battery life. Remove or limit the number of widgets displayed by swiping right on the home screen, scrolling to the bottom, and tapping Edit.
15. Adjust Auto-Lock Time: Shorten the auto-lock time on your iPhone. Go to Settings > Display & Brightness > Auto-Lock, and select a shorter time interval to turn off the screen more quickly when not in use.
16. Use Wi-Fi Instead of Cellular Data: When possible, connect to Wi-Fi networks instead of relying on cellular data. Using Wi-Fi consumes less power than using cellular data.
17. Enable Airplane Mode in Low or No Coverage Areas: When you're in an area with low or no cellular coverage, enabling Airplane Mode can prevent your iPhone from constantly searching for a signal and draining the battery.

By following these tips, you can help prolong the battery life of your iPhone and maintain its overall performance over time.

Note: This process has solved the battery drain problem for many people. I hope it will do the same for you!

shirshenduverma wrote:

the apple advisor agreed that this is an issue and after trying everything suggested factory reset?

Is the advisor still with Apple? I doubt it.