The device could track the battery's capacity pretty reliably by measuring inputs during charging and outputs during use. The necessary data is even available t

The device could track the battery's capacity pretty reliably by measuring inputs during charging and outputs during use. The necessary data is even available to third party apps on both iOS and MacOS (Battery Life, and Battery Health are two examples) It sounds like the idea is that the OS is throttling the performance to extend the battery life of a battery in poor condition, more than it sounds like it is limiting current draw to avoid "brownouts". I can see why this is a good idea and a bad idea, in that many people simply want a full day of being reachable on the phone more than they want smartphone features, but others who are considering replacement would like to know that a $100 fix would make their phone less frustrating.