Samsung S4 Active turning itself off I hope this is the right place to ask this question.

I'm using a Samsung S4 Active with stock Samsung-branded Android. Since I updated the OS from 4.2.2 to 4.4.2 my phone is sometimes turning itself off, trying to restart and failing, trying again. Maybe around 3 times until nothing is happening anymore.

The only way I can restart the phone is, that I connect it to power. Furthermore I feel that it only happens when my battery is lower than 60% - but still way higher than 0%!

I updated the phone via the Samsung-thingy which keeps popping up. So nothing external...

I factory-resetted my phone because I thought it might solve the problem - but unfortunately it didn't.

Any ideas what could be the solution for my problem? I googled quite a lot but couldn't come up with a hint...

Thanks,

Ron
Well, turned out that the battery was the problem. I invested 10€ for a new one and since one week no trouble at all.

Still thanks everybody!