Phone turns off at 40% battery

[Android Central Question]

Hi,

My xiaomi mi4c has a big problem, the battery discharges quickly and around 40 50% phone turns off with message "0 battery" but i turn on imediatly and battery is there where was before turning off, and from 40 or 50% keeps discharging to real 0%.But on night in sleep mod or inactivity its discharging a little bit, maybe 5% all night. Any clues or advises? Its rooted and has android 6, no auto brightness, no gps enabled or other thing like that... Its very annoying...

 

[Rukbat]

When you turn it on, go to Settings/Battery and tap on the graph. Look for a sharp drop to 0%. (It may be too narrow to see.)

That's the sign of a dendrite forming in the battery, and it means that the battery has to be replaced. (And dendrites aren't covered under any warranty I've ever seen. Batteries are considered consumables. Yes, it's unfair, and the industry is well aware of the problem, but there's nothing we can do if we don't want to carry heavy [like 2 or 3 pounds] batteries with us.)