iPhones batteries, like any other battery-powered devices, become less efficient as they age.
Although newer iPhones now have greater battery performance from the battery itself and the software managing it, the battery will eventually lose performance over time.
A quick and easy way to find out if your iPhone battery is still at peak performance is to go to Settings > Battery > Battery Health.
You’ll see the “Maximum Capacity” or how powerful your battery is in comparison to when it was new and the “Peak Performance Capability” underneath to let you know if it can fully support the capabilities of your iPhone.
Why is it important you say?
Glad you asked. You may simply wish to find out if your battery needs replacement, if you’ve had your iPhone for a while. In that case, you won’t need an Apple technician to run a complex diagnostic software to let you know if it needs replacement.
Also, if you’re buying a second-hand iPhone, this is a great way to find out if it’s worth buying. If it looks in mint condition on the outside but the battery clearly shows it’s dying, you could either drastically lower the price of the vendor or not buy it at all.
If you’re the one selling your old iPhone, then you could clearly show the true state of your battery and if it’s still in great condition, your potential buyers will be more likely to purchase it from you.
