Heavy battery drain since iOS 16.4

The carrier matters less than how strong the signal is, at least in this instance. Having a weak cellular signal will drain your battery like nobody's business. But, if that's not the issue....

To be honest, having a phone battery last 2-3 days is highly unusual. So, you got very lucky for a while.

I would suggest that you restore the phone to factory state and test. Also, stop force closing apps. That uses more battery life than leaving them open and suspended. The exceptions would be an app that is actually frozen.

If restoring it to factory state doesn't work, I would reach out to Apple and have them run diagnostics.

Genius Bar Reservation and Apple Support Options - Apple

Here are some quick troubleshooting steps you can try to improve battery life on your iPhone 13 Pro:

1. Check battery usage in Settings to identify power-hungry apps.

2. Restart your iPhone to resolve software glitches.

3. Reset all settings to default in Settings > General > Reset > Reset All Settings.

4. Disable unnecessary features like AirDrop, Background App Refresh, and Location Services.

5. Update all apps to the latest versions.

6. If the issue persists, consider restoring your iPhone to factory settings after backing up your data.

ngemas wrote:

In March '22 I purchased a new iPhone 13 Pro from an Apple Store. Everything was great, I'd get 2-3 days to a single charge, until iOS 16.4 dropped. Now I have to keep my phone plugged in ALL DAY to keep it charged. It's not a battery issue... this started happening with iOS 16.4, like night and day. If I leave it not plugged in overnight, it'll be 100% when I go to sleep and at 25% when I wake up. I have all apps closed, background app refresh turned off, and usually connected only to LTE cellular (not 5G, not WiFi). Currently running iOS 16.5 and if anything, the problem's gotten worse.

Go to Settings>Battery>Battery Health>Maximum Capacity. What is the percentage?

If the issues you have described are a direct result of the iOS 16.4 or iOS 16.4.1 update, it is highly likely that a substantial number of users who have performed the software upgrade are encountering a similar problem.

Without a precise understanding of the underlying issue, it may be challenging for forum members to provide targeted solutions to the difficulties you are encountering.

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.
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.
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.
4. Avoid Draining the Battery to Zero: Charge it whenever the charge becomes lower than 20%
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.
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.
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.
11. Limit Background App Activity: Close or force quit apps that are running in the background but are not needed. Double-press the home button (or swipe up from the bottom on iPhone X or later) and swipe away the unnecessary apps.
12. 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.
13. 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.
14. 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.
15. 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.
16. 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.
17. 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.
18. 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.
19. Disable Background App Refresh for Cellular Data: If you have limited data plans, consider disabling Background App Refresh for cellular data to reduce data usage and preserve battery life. You can find this option in Settings > General > Background App Refresh.

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

I think the point is that the issue of iPhone battery life decrease along with IOS updates.

For instance, battery life of iPhone 12 pro (86% health battery life) on IOS 16.5 is about 7hrs 40mins, and the battery life of the same model device (86% health battery life) on IOS 17.0.1 decreases to about 6hrs 39mins, according to youtuber, Dynamic Tech {

ip12 pro on ios16.5 7hrs40mins

ip12 pro on ios17.0.1 6hrs39mins

}

Any ideas that the reasons contribute these phenomena ?

ngemas wrote:

Maximum capacity is 88%.

Then that shouldn't be the issue.

What's your cellular signal like?

SravanKrA wrote:

Use Wi-Fi Instead of Cellular Data:1. When possible, connect to Wi-Fi networks instead of relying on cellular data. Using Wi-Fi consumes less power than using cellular data.

That is not exactly true.

Wi-Fi and Bluetooth Battery Drain and oth… - Apple Community