My phone keeps rebooting on its own.

[AC Question]

I use Huawei U8600-1 and yesterday I noticed that it keeps rebooting on its own.
I've did factory reset but it doesn't help much...I have had this problem before but it happened very rarely now it happens often and it's really annoying.
I've installed an antivirus program AVG but it found nothing. Any solutions? I would be very thankful! ^_^

 

[belodion]

A poor battery connection? A failing battery? A faulty power switch?

Also, does it persist in Safe Mode?

 

[JustMe011]

I tried safe mode but it's still the same... I don't know if it's the battery, it's charging properly.

 

[Rikku Watro]

This problem has been happening to one of my S4's too for about 3 1/2 months. It stopped randomly rebooting for about a week after New Year's Day, but after that, the problem happened again and persisted. Please help!

 

[JustMe011]

When I clean misc partition and cache it's OK for a longer time but it still happens sometimes. :-\