> Do you trust the quoted capacity figures, though?
Actually yes. Because even at 83%, my iPhone can last longer than its original battery's brand-new capacity. Also, I'm using Macs for ~15 years now and Coconut Battery's battery reports (which just interfaces with macOS battery information features) were always spot-on.
> but doesn't feel like it's holding that much charge, feels like it's due a replacement.
Actually, an iPhone's daily endurance depends on two things: Network connectivity & quality, and the apps you use. WiFi uses way less battery than cellular to begin with, and some applications "performance improvements and bug fixes" means "we have improved the performance of tracking you while using the app, and fixed the bugs about misreporting usage data". Applications like Instagram are so optimized at tracking its users, it drains my battery faster and heats my phone better than some games.
> to ensure for example that older stock still reports 100% when sold...
Low self discharge batteries are borderline magic. A low-discharge Li-Ion battery sitting at ~40% can sit there for years, if the cell is good. A low discharge Ni-MH battery can sit at ~90% for a decade. I recently opened a new blister of Eneloop AA batteries which were sitting there for a couple of years. All of them were at ~95% charge.
Actually yes. Because even at 83%, my iPhone can last longer than its original battery's brand-new capacity. Also, I'm using Macs for ~15 years now and Coconut Battery's battery reports (which just interfaces with macOS battery information features) were always spot-on.
> but doesn't feel like it's holding that much charge, feels like it's due a replacement.
Actually, an iPhone's daily endurance depends on two things: Network connectivity & quality, and the apps you use. WiFi uses way less battery than cellular to begin with, and some applications "performance improvements and bug fixes" means "we have improved the performance of tracking you while using the app, and fixed the bugs about misreporting usage data". Applications like Instagram are so optimized at tracking its users, it drains my battery faster and heats my phone better than some games.
> to ensure for example that older stock still reports 100% when sold...
Low self discharge batteries are borderline magic. A low-discharge Li-Ion battery sitting at ~40% can sit there for years, if the cell is good. A low discharge Ni-MH battery can sit at ~90% for a decade. I recently opened a new blister of Eneloop AA batteries which were sitting there for a couple of years. All of them were at ~95% charge.