Check iPhone 7 battery health
If I replace a new iPhone 7 battery in the after-market, can the iOS 11.3 check my battery health?
If you buy the newest battery made and shipped from China, it can be checked by the iOS 11.3. The manufacturers have updated the battery IC data.
that depends on the quality of aftermarket battery you get.
There is a voltage filter that it needs to be able to take measurements off of to run the tests. if it is a 5-19$ battery, probably not. but if youre buying a 30-40$ battery, it is quite possible the required components are there. However, you can never be sure with 3rd party.