Bar on I phone
Why does my apple 13 I phone only have 1 bar when it’s fully charged?
iPhone 13 Pro Max, iOS 16
Question marked as
If you are referring to the bar circled in red:
That is simply an indication of you much service you have, and is unrelated to the battery.
From the little battery icon, straight right of the bars, one can see that your battery is 100% fully charged.
To help you better determine how full the battery is, you may want to turn on “Battery Percentage” at: Settings > Battery. Now, at the top, turn ON “Battery Percentage”.
Here is what you will see:
Good Luck!