my phone droped 12 percent bettry health in just 7 month

Batteries degrade over time with usage due to chemical aging, that's just how they work.

You can expect about a 1% drop per month with average use on an iPhone. This is an approximation, that is why it may be plus or minus a few percent on a month to month basis.

Apple recommends replacing it when it reaches 80%. To check your battery health, go to Settings > Battery > Battery Health.

iPhone Battery Replacement.

https://support.apple.com/iphone/repair/service/battery-power

About Lithium Ion Batteries

https://support.apple.com/en-in/HT208387

Here are some tips on maximizing battery life.

https://www.apple.com/batteries/maximizing-performance/

sanju158 Said:

"My I phone 14 dropped 12 percent battery health in just 7 month"

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Get this Serviced:

There may be Debris:

Strangely, after I had Apple service my iPhone due to a draining battery, and the battery draining stopped like a charm. I was told that there was debris in the charging port. So, set up a Genius Bar Appointment at your local Apple Store.  There it will be looked at and you'll be provided with your options. Its Battery Health is at 88%, is 3 years old, and is still working just fine.