Cell phone keeps turning off although is fully charged.

My phone keeps turning off by itself. ' Android Forums

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Sep 22, 2015 - Um my phone keeps turning off by itself. And its really really starting to get annoying. IDK if it was some app or an update. Anyone else having ... Phone unexpectedly shutting off without notice
Feb 2, 2016
help.my phone keeps turning on and off by itself
Dec 23, 2015
Randomly Turning Off?
Oct 26, 2015
Phone keeps shutting off by itself
Mar 26, 2015
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My Phone Keeps turning off and then turning itself back on ...

https://www.ifixit.com/.../My+Phone+Keeps+turning+off+and+then...

iFixitwhen i turn on my phone and it does its power up, i wait for my service to come on. before the service gets turned on the phone restarts itself everytime. it ...

Battery may not be charged enough to run the phone. Keep the phone off and connect it to a charger to fully charge the battery or use an external battery charger.
Be sure the The micro usb connector is fully seated and that the battery is actually charging. A loose connection may appear to start the charging process, but if its loose, it may not be continuing to charge. Check the % progress.

Dear User,
This is a battery problem. please replace it.

Chances are your phone got too hot during the night and overcharged the Lithium Ion battery. If those batteries are exposed to too much heat then they won't have the battery life they used to have. You need to purchase a replacement battery or contact your wireless carrier to see about getting another one.

Check that the power button isn't stuck partially depressed. If that isn't it, you've got issues inside the phone that are going to require qualified service, or an internally damaged battery.

Hi there!
Since you've mentioned that your phone keeps on turning off then ill be advising you to please check if your battery is properly holding a charge because it might be that your phone doesn't have enough power.so if the problem is your battery then kindly purchase a new one to prevent other issues.
Thanks!

hiiiiii dear this may be a solution that make back up of data & format the cell

Have you tried to update the phone's software/firmware? You should be able to get the update software from Sony Ericsson website and follow the instruction. Hope it helps.

try replacing your battery

wait until the phones battry get fully chrged working with a fully drained battery is bad to phone as wellas battery itself