Battery percentage suddenly decreased

Which iPhone do you have? Your battery health decreased from which percentage to which percentage?

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Your battery health is undergoing normal usage. iPhone batteries, like all rechargeable batteries, are consumable components that become less effective as they age. You should change out the battery once your Battery Health reaches below 80% which will take over 2 years to reach under normal usage. Until then enjoy your iPhone.

One other thing to note is that The battery health measurement process is not an exact science and its rather a process of approximation. This means that there is no set amount of percentage that the battery will degrade every month, however, it will degrade and eventually will get reported.

Here is some more reading on an iPhone battery and its performance ➡️ iPhone Battery and Performance - Apple Support

Axel F.

Batteries degrade over time with usage, that's just how they work.

You can expect about a 1% drop per month with average use on an iPhone.

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

iPhone Battery Replacement.

iPhone Battery Repair & Replacement - Apple Support

About Lithium Ion Batteries

iPhone Battery and Performance - Apple Support (IN)

Here are some tips on maximizing battery life.

Batteries - Maximizing Performance - Apple