iPhone XS switching off at 40%

[Kainz]

Age of the battery and cycle count are much more important.

Exactly. I can't see how Apple just didn't use this instead. Batt Health to me now is absolute BS. I briefly spoke to the chap who changed my battery and he said the battery was absolutely depleted seeing as it was at that point shutting off at 60%. '91% Battery Health indeed'.

 

[No-One]

My old iPhone 6 came with a battery which seemed to far exceed the charge capacity specs. By the time the phone was 4 years old it had lost the capability to provide peak power under heavy load causing the phone to throttle but the charge capacity was still above spec. (Somewhere over 2000 mAh I think) which caused the battery health to still show 100%. I got the battery replaced at the Apple store but the guy seemed confused to see it still showing 100%.

 

[Scougar]

Colleague of mine is an ex-dev for Apple, and spoke to me a few years ago about the battery issues.

When batteries start to degrade, high performance app's won't run properly or not at all because the battery can't provide enough power for the requirements. They basically keep band-aiding it in software to account for poor batteries. And that's the reality, that as batteries age, they just don't perform as well and create a whole raft of problems. The fact that batteries are non-removable just adds to the whole e-waste issue, as I suspect a lot of issues of phones comes down to a bad battery and not the phone itself.