Apple’s iOS 13 will save your iPhone’s battery – by not fully charging it

Josh Hendrickson for How-To Geek:

Lithium-ion batteries, like those in iPhones, have a longer usable life if you don’t charge above 80%. But, to last the day, you probably want a full charge. With iOS 13, Apple may give you the best of both worlds.

Apple announced iOS 13 at WWDC 2019. Buried in the list of extra features was a note about “battery optimization.” Apple says it will be “reducing the time your iPhone spends fully charged.” Specifically, Apple will prevent your iPhone from charging above 80% until you need it.

You might be wondering why Apple wants to keep your iPhone at 80% charge. It’s all about the way Lithium-ion battery technology works.

Lithium-ion Battery Charging
Source: Apple Inc.

Earlier rechargeable technology suffered from the memory effect — essentially, batteries lost track of their maximum capacities if you constantly recharged them after only partially discharging them. Lithium-ion batteries don’t have that problem. If you’re still draining your battery to empty before recharging it, you should stop. You’re damaging your battery’s health.

In iOS 13, a new charging algorithm will keep your iPhone at 80% when charging overnight. That algorithm will determine when you typically wake up and start the day, and restart the charging sequence to give you fully charged battery when you wake up.

MacDailyNews Take: iOS 13 has extra smart battery charging built right in!

And, again, just to reiterate: Don’t run your iPhone down to zero if you can help it and keep it on charge whenever possible.

We just checked a Day One (November 3, 2017) iPhone X that is basically connected to a charger 20 hours per day. Settings > Battery > Battery Health. The iPhone was always on charge whenever possible. Its battery currently has a maximum capacity of 96%.

See also: I used an iPhone X for a year and had 99% battery health – here’s how I did it.

[Thanks to MacDailyNews Reader “Brawndo Drinker” for the heads up.]


  1. I love all of the stuff they’ve done with battery management, now if they could only put in higher capacity batteries without making the phone thicker and ship it with a decently powerful fast charger that would be amazing.

    1. They Gave me a brand-new replacement 6 Plus shortly after my AppleCare Plus expired due to dying battery- and being a longstanding family customer. My wife got a 7 Plus for free when hers died within warranty. Than and my new X are still going strong- will upgrade this year or next.

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