Does the phone show the battery at a critical percentage after turning on?
I had a similar issue a while back with my HTC one.I knew it was definately the battery.
It is not 100% however it may be due to the battery,either hardware or software.
Phones may turn off prematurely if the phone thinks it has a low battery.
to resolve this you can do a complete cycle.Draining the battery to 0% and then charging to 100%.
If this does not work you may try clearing the batterystats.bin with a third party app that may be found on the market.However this requires root access.
If hardware is where the issue lies the only way is to get a replacement.
If this has not worked or the battery is not the problem reply on this very thread about the symptoms and we'll see,but for now give that a go.
12-27-2015 09:20 AM