iPhone battery problem iOS 18.2 or ?

CristianCH wrote:

100 can appear again during an update or I can downgrade it

All batteries degrade.

Always.

That iPhone will fail.

Inevitably.

The difference here from most batteries is a display showing a digital estimate of an analog degradation process; of the battery state.

The inexorable battery degradation process is seldom linear, too. Sometimes it goes faster, sometimes slower. Battery chemistry, battery environment, usage, there are multiple factors.

When the battery drops to 80% or below, get the battery replaced, or get the iPhone recycled and replaced.

Consider the battery health display to be green 🟢 from, say, 100 to 81%, then yellow 🟡 for, say, 80% to 70%, then red 🔴 when the battery ceases to battery, and requires tethering to a charger.

From Apple:

• Batteries - Maximizing Performance - Apple
• Batteries - Apple

It only decreased 1%. That’s hardly a drastic decrease.

Batteries, like people are individuals. No two people age exactly the same and batteries don’t age the same either. The exact usage, chemical makeup, storage conditions, exposure to heat and cold and about a dozen other factors mean that every battery ages differently. Battery aging is not a linear (straight line) and degrades at different rates as the chemicals in the battery age and other factors mentioned above. Apple expects your battery health to be at 80% after 24 months. If your battery health misses that expectation, contact Apple Support.

Please review the Apple Support articles on battery optimization. It contains the best  current practices for battery charging.

iPhone Battery and Performance - Apple Support

Batteries - Maximizing Performance - Apple

About the battery and performance of iPhone 11 and later - Apple Support

It is much too soon to try to make a determination of the performance of your battery, but after 100 charge cycles, the Battery Health should be about 97-98%.

After 200 charge cycles, the Battery Health will be at about 95-96%.

Please keep in mind that due to the manner in which Apple displays Battery Health numbers, there are no tenth of a percent displays. The number is always rounded down.

For example, the battery might really be at 99.9%, but that number will be displayed as 99%.

So, the battery might look like it declined by 1%, when it really only declined by .1%.

Wait until the battery has completed 100 charge cycles and then post back at that time with the Battery Health readings.

CristianCH wrote:

100 can appear again during an update or I can downgrade it

No it can't appear again. Battery Health goes in one direction ONLY and that is down. You are worrying over something, which is normal and can't be stopped. As others have said a 1% decline in Battery Health is hardly reason for concern. It is quite normal to see about a 1% drop in Battery Health per month. When the day comes that your battery dips to 80%, which is ABSOLUTELY WILL do at some point in the future, it will then be time to pay Apple to replace the battery. In the meantime worrying over something you can't stop is a waste of emotion.

No, just like I wrote, no two batteries are the alike. Some drop in after 20 plus charge cycles, some drop with 50+ charge cycles, some last 100 or more charge cycles.

There is nothing wrong with your battery.

100% will never appear again unless you replace the battery. But, you don't need to replace the battery unless it is down to 80%.

Battery 2 months old