why galaxy tab sm-t550 won`t turn on when battery is under 50%?

[AC Question]

hi when i bought my galaxy tab A everything was fine, but now if battery is charged under 50% it turns on just for a few secs and display is flashing , i can see charging motion when i plug charger into device, if battery is fully charged then it`s working fine for about hour

 

[belodion]

A faulty battery?