Your iPhone battery and its performance
How do I optimize battery performance?
Smartphones today are great at managing battery performance themselves, however the main thing you can to take care of your batter is to keep it away from heat. Heat will degrade a battery faster. In all other conditions, just use your phone as you normally would, although Apple does suggest that if you are storing your phone for the long term, it’s best to keep it half-charged.
Do batteries chemically age?
Due to their chemistry, the Li-ion batteries in our phones all have a set lifespan which for most is when they reach 80% of their original capacity. iPhone batteries are rated to degrade to these levels after 500 charge cycles, meaning if you completely drain your phone and recharge it every night, this level will be reached in less than two years.
How does my Iphone prevent unexpected shutdowns?
In a low state of charge, a higher chemical age, and in colder temperatures, you are more likely to experience unexpected shutdowns. However, your iPhone dynamically manages performance peaks (sometimes slowing performance) to prevent the device from unexpectedly shutting down so that the device can still be used.
How to find out the state of your iPhone’s battery health
For iPhone 6 and later, iOS 11.3 and later, you can see your battery health with a recommendation if the battery needs replacing. This can be found in Settings > Battery > Battery Health. Whatever the recommendation however, you should look at replacing your iPhone battery when it reaches 80% health, you find it no longer meets your needs, or when the system performance is no longer at its peak.