As part of its penance for the throttling, Cupertino has reduced the cost of a battery replacement down to $29. Apple is also facing a U.S. House inquiry over the throttling of devices. Apple has now announced some new battery features that are available in iOS 11.3 Beta 2 that add in a new method for people to see if their aging battery is affecting system performance. The new feature is called "Battery Health" and when your battery is just fine, you will see the screen below.
However, if your battery has degraded and you are facing performance throttling, you will see the second screen below. The screen shows what your maximum battery capacity is in percentage form and then calls out that performance management is enabled. You can disable that throttling directly from the Peak Performance Capability section of the screen. Performance management is off on all devices by default but turns on automatically if an unexpected shutdown occurs.
Apple wrote in an updated support document, "iOS 11.3 improves this performance management feature by periodically assessing the level of performance management necessary to avoid unexpected shutdowns. If the battery health is able to support the observed peak power requirements, the amount of performance management will be lowered. If an unexpected shutdown occurs again, then performance management will increase. This assessment is ongoing, allowing more adaptive performance management.
"iPhone 8, iPhone 8 Plus, and iPhone X models use a more advanced hardware and software design that provides a more accurate estimation of both power needs and the battery’s power capability to maximize overall system performance. This allows a different performance management system that more precisely allows iOS to anticipate and avoid an unexpected shutdown. As a result, the impacts of performance management may be less noticeable on iPhone 8, iPhone 8 Plus, and iPhone X."