Why is my iPhone 6 Plus dying with 30% battery left?

[iMore Question]

My phone shuts down with 20 to 30 percent battery left.

 

[anon(10101748)]

Don't quote me, but search the forums. pretty sure it's known by Apple and they are replacing batteries on certain devices made between certain dates. Call Apple and then make a Genius Bar appointment for a battery replacement if you are given one.

 

[Jezza23]

Is it the s or the 6? If it is the 6s, I heard that Apple is replacing some batteries which might be faulty.