iPhone 15 battery health decline after every 4-5 charge cycles

dibakar257 wrote:

At 297 cycles, it was 94%. Currently, it’s 91% with 308 charge cycles.

As per iPhone 15 battery, it should be 1000 charge cycles, so as per that, every 1% should be 50 cycle count.

So in 308 cycles, it should be around 93%.

Your assessment is pretty accurate and you are within 2% of what Apple recommends under ideal conditions. Not something that would indicate any red flags. As already stated, the drop is not going to be linear, meaning that it is only tied to charge cycles where every 50 would automatically drop the Battery Health by 1%. Previous drops do not indicate that future drops will be the same.

The drop is not linear, it may drop faster at times and slower at other times

You are overthinking this, just enjoy your phone and replace the battery when it reaches 80%

Lithium batteries do not age in a linear fashion. This is just physics and chemistry in operation. You’ll find that your iPhone battery health will drop off and then hit a plateau where the health remains steady for an unusually long time.

For example I’ve an older iPhone 14 PM that gets charged daily and is stuck on 82% for last 3 months. I’m expecting a 3 or 4 point dip any day now.

When it gets to 79% get a new battery fitted by Apple. Stuff wears out.

What is your Battery Health and your Charge Cycles? The rate of decline is not linear and has no effect on future declines. Your battery is expected to last 1000 charge cycles before it will need to be replaced when the Battery Health drops below 80%.

If it dropped 9% with 308 charge cycles, that would be a drop of 1% every 34 charge cycles, not 4-5.

dibakar257 wrote:

308 charge cycle with 91% health.

No problem

dibakar257 wrote:

At 297 cycles, it was 94%. Currently, it’s 91% with 308 charge cycles.

As per iPhone 15 battery, it should be 1000 charge cycles, so as per that, every 1% should be 50 cycle count.

So in 308 cycles, it should be around 93%.

What it should be in theory is not always what it is in reality. The specs are determined under ideal conditions. I know I don't live in an ideal world.

Also, it has been explained that the decrease in capacity is not linear.

And it's an estimate.