Apple has made a new battery health tool available on beta and you’ll want to download it on your iPhone. The iOS 11.3 beta that has a feature letting users check the health of an iPhone. Sign up for their public beta program to get the update.
iOS 11.3 Beta Phase
When signing up and testing Apple’s latest software update, remember that it’s a little rough around the edges. You’ll likely experience apps randomly crashing or battery performance issues. That is natural as Apple continually improves their product until its official release sometime this spring.
Checking the Battery
Once you’ve installed iOS 11.3 on your iPhone, navigate to Settings > Battery > Battery Health (Beta).
You’ll find a section on the Battery Settings page that shows details on your iPhone’s battery’s health.
Shown are your battery’s current state and a description of how its health impacts your device’s performance. You will be informed if your iPhone is being throttled and will be provided an option to disable the feature.
In the event that your iPhone randomly shuts down due to battery health issues, the feature will enable itself automatically. The protocol prevents future random shutdowns by design. You will be instructed to have your device tested (or possibly replaced) at an authorized service center or an Apple Store when iOS can’t determine the health level of your battery or it’s already dangerously low.
iOS 11.3 beta may only be a temporary remedy to slowing iPhones, but it should help address the problem sooner.