Xperia Z3 plus turns off at 50% battery

[aripel]

I own the phone for more than a year and I have a problem

I have 50% of battery and the phone turns off and tells me that battery is dead..I plug the charger it shows me that I have 55%
What is wrong?
Should the battery be changed?

[GLea]

In the end I bought a battery described as original, the battery remains still at 20%, the phone does not even turn on and the phone is unusable.

A pity, the cell phone will remain in a drawer.
Bye.