Battery issue in iphone 15 plus

Drewdeeezy wrote:

I bought my iPhone 15 plus in October 23, my cycle count is at like 140 but my battery is still at 100% I let it charge to 80% never above, and never under 25%.

You are lucky; you got a battery that exceeded Apple’s maximum capacity specification.

That’s not true, 1% for 25 cycles…do the math, and you’ll see how ridiculous that is. iPhone shows 1000 cycles at 80% capacity on iPhone 15. At the above rate, people would be screaming. I’m at 32 right now and 100%, and my phones not “special”. Geez.

98% is exactly what should be expected after 2 months. Batteries are consumables; they lose a little capacity every time they are discharged, then recharged. On average this works out to about a 1% loss for every 25 “full charge cycles”. As one example, if you charge the phone overnight, every night (and that is what you should do; it is a best practice), it starts the day at 100%. If it drops to 20% by the end of the day before you charge it again overnight that counts as 0.8 full charge cycles (20% to 100%), or about 24 full charge cycles per month of use. For this example your battery capacity will lose about 1% per month. Of course, if the end-of-day level is higher than 20% the capacity loss will be a little less, and if it is lower than 20%, or you charge it during the day, the capacity loss will be higher.

Once the capacity drops below 80%, or if there is a message in Battery Health that the battery is not meeting peak performance expectations, it’s time to change the battery→iPhone Battery Replacement - Official Apple Support

The absolute best way to get maximum use on a charge, as well as slow the decline of battery capacity long term is to enable Optimized Battery Charging (Settings/Battery/Battery Health) and charge the device overnight, every night. The battery will fast charge to 80%, then pause. During the nighttime pause the phone will use mains power instead of battery power, allowing the battery to “rest”, and thus reducing the need to charge the battery quite as often. The phone will resume charging to reach 100% when you are ready to use your phone; it will “learn” your usage pattern. If you enable iCloud Backup (Settings/[your name]/iCloud - iCloud Backup) the phone will back up overnight also, assuring that you can never lose more than the current day’s updates. Here's more information→About Optimized Battery Charging on your iPhone - Apple Support

My cycle count is only 31 but battery health is at 98 % in 1 and a half month :( I have 80% limit selected. Should I charge overnight then? Keep it plugged?

How do they keep the battery health? Mine’s 98% 31 cycle :( 80% limit when charging

It will lose 1% for each 25 cycles. So at 40 cycles it should be down 1.6% and show 98.4%, but since only the whole digits are displayed it will show 98%, which is what you said you see.

It is not possible to overcharge your phone; the built in charger makes sure by stopping at 100% (or 80% if you have Optimized Charging or 80% enabled).

However, leaving the phone plugged in overnight with either Optimized or 80% limited actually extends the life of the battery, because the energy used by the phone overnight comes from the power mains rather than the battery.

Your friend was lucky, and got a phone with a battery that exceeded its minimum specifications.

A battery is a chemical device, and chemistry is generally pretty variable and uncertain, as well as being analog, not digital. Apple specs the battery capacity to remain above 80% for 500 full charge cycles, 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.

Amaaan099 wrote:

I had 109 cycle count and after updating to 17.4 it went to 99, I am so not happy, I have seen people using 15 plus with charge cylce 130 plus and still it's running at 100% battery health

You are lucky; you got a battery that exceeded Apple’s maximum capacity specification.

The specification for iPhone battery capacity works out to a 1% drop for every 25 full charge cycles; based on this your battery should be at 95%, so 99% is really great!

I bought my iPhone 15 plus in October 23, my cycle count is at like 140 but my battery is still at 100% I let it charge to 80% never above, and never under 25%.

I had 109 cycle count and after updating to 17.4 it went to 99, I am so not happy, I have seen people using 15 plus with charge cylce 130 plus and still it's running at 100% battery health

I have 15 plus it falls out 100 to 98 battery health at 31 cycles 🥲