Battery Health vs. Battery Life
Battery health is different than battery life. Battery life determines how long your battery lasts on a single charge, but your battery health determines how much your battery life diminishes over time. After a year, your battery life won’t be as long as when the phone was new, and it will continue to degrade as the years go by.
If you’ve ever had to constantly recharge your older phone because the battery would only last a couple of hours, then you know how annoying this is. Compounding the problem is that most mobile phones don’t have a user-accessible battery that can be swapped out with a new, fresh battery.
Fortunately, there are two excellent metrics you can check to get a big picture view of your battery’s health. The first is the maximum remaining capacity (the total charge your battery can hold). The second is the total number of charge cycles the battery has gone through.
Real world use always chips away at the total capacity over time, but a healthy battery will have only a few percents shaved off its original capacity. Furthermore, lithium-ion batteries (those found in pretty much every smartphone) degrade a tiny bit with each charge cycle. Apple says they design their iPhone batteries so that the battery should retain roughly 80% of its capacity after 500 charges.
For older iPhone users that aren’t able to update their devices to at least iOS 11.3, skip on to the following sections below, but if you’re currently running iOS 11.3 and have an iPhone 6 or newer, you can look up the battery health right in the settings.
Open up the settings app, and then navigate to Battery > Battery Health. From there, you’ll see a percentage next to “Maximum Capacity,” which gives you a good idea of whether or not your iPhone’s battery is in good health—the higher the percentage, the better.
Below that, you’ll see how your iPhone is performing based on the battery health in the small text below “Peak Performance Capability.” For batteries in good shape, you’ll probably see “Your battery is currently supporting normal peak performance.” Otherwise, you might see a different message if your battery is degraded at all.
In years past, if you wanted to know the battery health status of your iPhone, you’d have to take it to an Apple Store and let them run a diagnostic test. However, this kind of thing can be done remotely, too. Thus, it’s perhaps the best way to get this kind of info.
Basically, they’ll tell you to DM them, and you’ll give them your iPhone’s serial number and iOS version. They’ll then approve you for a diagnostics test which you’ll access in the settings app. Once it’s done running, you’ll let the support rep know, and then they’ll let you know about the status of your battery’s health. Pretty cool!