You are almost out of battery, but really at 40%

Hello Dakul,

Thanks for inquiring about the iPhone battery here within the Apple Communities. I appreciate the amount of detail about your iOS version, the device, your actions and how the iPhone reacts offered with your question. Yes, this topic can be considered iPhone software, or iOS, or the battery directly, which falls under this hardware thread. We need to isolate the battery not offering the correct amount of power left for use with the device from some issue within the iOS or your personal data on the device, and the battery hardware. The first step, is to make a backup of all your data in iTunes or iCloud to ensure your data is safe. How to back up your devices using iCloud or iTunes

Then, you will need to erase your personal data and set the phone up as new using iTunes. This must be done through iTunes. This article offers the instructions, and pictures for easy completion. Use iTunes on your Mac or PC to restore your iPhone, iPad, or iPod to factory settings. You will be setting up the phone as new, and not bringing back any personal data, or restoring from the backups at this time.

Once the phone is set up as new, you will test to see if the battery issues are happening without your personal data on the device. If not, we know the issue was with some data on the device or in the iOS version, which will also be in you backups. You can manually bring data back using iCloud or iTunes, but do not restore from the backup as you will bring the problem right back in. These articles will help: Sync your iPhone, iPad, or iPod touch with iTunes on your computer using USB OR Sync media between your iPhone, iPad, or iPod touch and iTunes on your Mac or PC

If the battery issues do still occur with no personal data, then we need the phone hardware checked at an Apple Authorized Service Provider or an Apple Retail Store. You can set up a mail in repair if you are in an area that offers that, using this link: Mail-in Start a service request link or you can find an Apple Authorized Service Provider or Apple Retail Store using this link: Apple find locations

Cheers.

I have the exact problem. Another friend of mine just complained about the same problem, so this must be a software bug. Both of us have our phones indicating 40%. Then they just shut off. When you try to turn phone on, it shows the battery empty and indicates it needs to be plugged in. Then you plug it in, and instantly, you can turn the phone back on and it's back at 40% again.

Common Apple! What's with all the buggy software? We were all discussing how this sort of this is becoming common place with Apple now. We're about to jump ship to another ecosystem if this continues.

Hi

There is an iPhone 6s Program for Unexpected Shutdown Issues.

Follow the instructions here to check your iPhone's eligibility for a free battery replacement:

https://www.apple.com/support/iphone6s-unexpectedshutdown/