How do I fix rapid battery drain on my iPhone?

I prefer you to turn off Background App refresh which you will find in Settings—>General—> Background App Refresh. Also charge your phone to till 80% only change to 100% when it is emergency to go out. Make location Services to use while app is in use this you will find in Settings-> Privacy & Security-> Location Services. If you are using pro devices turn off Always On Display.Never use phone Will charging and use a Apple genuine product to charge your phone.

A battery is a chemical device, and chemistry is generally pretty variable and uncertain, as well as being nasty analog, not happy digital. Apple specs the battery capacity to remain above 80% for 500 full charge cycles (1,000 for iPhone 15 and newer), but that is a minimum requirement; there is no published maximum expected capacity. So sometimes batteries will perform much better than that minimum specification, and sometimes the change in maximum capacity won't be linear. There is no way to predict in advance what the real-life performance of any specific battery will be.

All iPhones have a specification for the battery. As an example, for the iPhone 14 Pro that is 3200 milliampere-hours (MaH). So the battery monitor is calibrated for 100% at that value. But there are variations in manufacturing, so some batteries will have less capacity, and some will have more. Suppose your battery had, say, 3520 MaH capacity (10% over standard). That would still show as 100% (even though it was actually 110%), but as it aged the health would stay at 100% until it fell below 3200 MaH. This would appear to you as if the battery had fabulous life, until suddenly it didn’t.

TonyAppleOS wrote:

I prefer you to turn off Background App refresh which you will find in Settings—>General—> Background App Refresh. Also charge your phone to till 80% only change to 100% when it is emergency to go out. Make location Services to use while app is in use this you will find in Settings-> Privacy & Security-> Location Services. If you are using pro devices turn off Always On Display.Never use phone Will charging and use a Apple genuine product to charge your phone.

Actually, none of that will make any real difference in battery drain. And it is actually better to charge when using the iPhone, because the power to run the phone and apps will come from the external power source, thus reducing the need to charge frequently. Large battery drain comes from apps using a lot of power, not from things that use minuscule energy, like Always On Display and Background App Refresh - if you disable background app refresh then the apps that would have updated in background will update when those apps are in use, thus consuming the same amount of energy, just shifted in time.

MirkoBurhan wrote:

Thanks man for the past help.

But now I am more sad because my iPhone's battery capacity has dropped to 94!

And i think it is a software issue, so i want to sell it.

Well, the next one, and the next one, and the next one, regardless of manufacturer, will all lose battery capacity every time they are discharged, then charged. Once they drop to 80% the battery should be replaced.

What is your cycle count now?

What model iPhone, and how long has it been since it was new?

And what is current max capacity, and what is the number of charge cycles?

That’s exactly where it should be. It will lose 1% capacity for every 50 cycles.