What wrong with my battery

Hello,

These are the standard steps for short battery life: 

1) Have you tried a restart?  If not, do it now.

2) Go to Settings > Battery > BATTERY USAGE BY APP to see the apps that are consuming your battery.

3) Check “Battery Health” in the link: 

iPhone Battery and Performance

4) If all else fails, consider a battery replacement:

iPhone Battery Service

Good luck.

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