IOS 13.4.1 Battery drain so fast !!!!

It depends on the usage. How has your usage changed after iOS update.

Protect & Prolong life of your iPhone's Battery: About the battery usage on your iPhone, iPad, and iPod touch ...

Try some of these options too.

1. Avoid Screen Mirroring
2. Put on Low Power Mode
3. Put Auto Lock On (1 min):- with low power mode it will be 30 Sec
4. Put Auto Answer Off
5. Disable Push notifications for apps you do not use often
6. Enable Auto Brightness:- Settings > General > Accessibility > Display Accommodations > Auto-Brightness [Enable]
7. Manually lower brightness from Control Center
8. If you Want to watch continuous Video. Stream it on TV or a Monitor
9. Don't force close apps; Apps which are not on frontend screen are paused by the system to save energy. Apps require more energy to re-launch. Apps which are open in the background use large memory is a myth and quitting them is counterproductive
10. Location services to be allowed only while using the app
11. Set your iPhone to fetch email and calendar data from internet less frequently
12. Turning off Background App Refresh 
13. Charge before it drops below 20-30%
14. Try connecting to trusted Wifi where ever available in stead of Cellular
15. Enable Airplane mode in areas with bad cellular and wifi coverage. Your phone keeps trying for reconnection with the missing / weak network. This uses lot of energy
16. Switch off Wifi & Bluetooth while in Roaming or Not in Range
17. Enable "Wifi Assist" : Settings > Cellular or Settings > Mobile Data > Wi-Fi Assist [Enable]
18. Periodically Check your Battery Health (Settings > Battery > Battery Health)

iPhone Battery and Performance

We know how to use our devices but I appreciate the long list for people who don't. However, it is clear that 13.4.1 has a battery drain issue. Check the forums here, Reddit, MacRumors, etc.

It's a bug.

I think I may have isolated the problem at least for some iPhone models. This is only day one though.

Another poster commented about an issue with a SIM card and LTE which didn't make much sense to me except that if 13.4.1/13.5 contained a modem issue that was draining battery.

I had VoLTE (Voice over LTE) turned OFF but it seems that iOS 13's new menu system turned this back on. Turning VoLTE Off (Settings > Cellular Data Options > Voice & Data > LTE, VoLTE Off) seems to have improved the battery today although I have not used the device as much today. However, I am not seeing the dramatic IDLE battery loss as I was before.

It may be a starting point so please try turning VoLTE off and reporting your findings to all of us. If we find that this is the issue maybe we can submit a more detailed bug report. (For iPhones or perhaps iPads that have an LTE modem -- which would require LTE off entirely if this was the same problem)...

So, I have two suggestions:

Turn off VoLTE if you have the option. See how the device operates over the next 24 hours.

If you have an iPad/don't have a VoLTE option, turn off LTE and see how the device operates over the next 24 hours.

Let us know if this solves anything at all and then we may find the source of this bug.

My iPhone battery draining problems started after the recent IOS 13.5.1 update. Till 13.4.1 all was fine. Resetting has not solved the problem. Any one can advice?

what is Apple customer service saying about this?

Apple GM of Seoul flagship store told me that I was a liar and that everyone on these forums are just using it as a quote "giant echo chamber" and pretending to have problems.

I have since reset and sold my iPhone and purchased a Galaxy S20 Ultra.

iPhone issues solved. 13 years of loyalty OVER AND OUT.

Apple just degraded and insulted me. Samsung gave me free gifts and $150 worth of extra free gear when I switched. Apple just gave me a sick feeling in the pit of my stomach. 🙃🙃🙃🙃🙃🙃🙃🙃

Same problem (iPhone 11 Pro Max) - I’ve been researching this for some time. I now believe it is some sort of synchronization thrashing problem. This worked for me:

Log out of your Apple account.

Log back in.

I chose to “remove” data like contacts, etc. which is an option when logging out of your Apple account.

Another poster elected to keep local data and then did a “merge” when he logged back in Which worked for him.

I also reset my network settings but I’m not sure this was necessary.

Same here buddy. I am facing the same problem.