[arder]

It's difficult to see when the 80% will ever pay off. They're a year in and he's got 94% health - but with that limit in place that's an effective battery capacity of 73% (0.94*0.8). At the rate that the others' batteries are degrading it's going to be close to 2 years before they even hit 80% capacity let alone the 60-70% that would make the 80% limited battery have better total real battery time. And at that point what are we saying? You're trading a good chunk of your battery in the first two years of its life for a few percent more several years into owning the phone?

It seems difficult from these numbers to see when, if ever, this choice is going to pay off for the people who opt in.

[Mistletoe]

I suspect it was conceived for Apple to prevent having to replace batteries under warranty.

[Marsymars]

Seems like if that was Apple's goal, it would be easier for them to just reduce the quoted battery life of the phone, limit the charge to 80% for everyone, and relabel the 0-80 scale to 0-100.

Presumably, they've already effectively done this by choosing voltage amounts that balance warranty repairs with battery life. e.g. the iPhone 15 charges to a max of 4.48V, but the battery presumably physically supports some higher voltage for "100%" that would give more capacity and less lifespan. (Notably, different iPhone models have different voltage ranges.)

[CaptainMarvel]

The older feature of limiting charge to 80% only overnight was more useful in my opinion.