The best macOS feature you don’t know you’re using: Optimized Battery Charging

As you probably know, a battery’s charge capacity diminishes over time. If you’ve recently got an M-series MacBook, you spent a good amount of money on that laptop, so you want the battery to be viable as long as possible. Fortunately, macOS has built-in ways to help maintain your battery’s condition.

In macOS Sonoma, the Battery System Setting provides good information you can use to determine your battery’s health. There’s a chart that displays your battery charge level over the last 24 hours and the last 10 days. Another chart shows screen usage–the MacBook’s screen is one of the most power-hungry components.

But there’s a setting that’s not obvious in the Battery tab in System Settings. It’s called Optimized Battery Charging, and we’ll cover what it’s about and why you should be using it.

What is Optimize Battery Charging?

In macOS Catalina, Apple introduced a Battery Health Management setting that evolved into Optimized Battery Charging in later versions of macOS. Optimized Battery Charging “learns from your daily charging routine so it can wait to finish charging past 80 percent until you need to use it on battery” to slow down the battery aging process, according to Apple.

In other words, with Optimized Battery Charging on, the MacBook battery charges to 80 percent and stops. Then, macOS uses an algorithm based on your usage to determine when the battery should be charged to 100 percent.

If you have a regular daily routine, this setting works well. For example, if you usually spend the mornings using your MacBook on battery, and then the afternoons and evenings are plugged in, Optimized Battery Charging can set the charging cycle so that the battery is charged up to 80 percent after you plug in, then charge to 100 percent before you go on battery in the morning. 

Many Macworld readers have noticed that even with Optimized Battery Charging on, the MacBook battery gets charged to 100 percent, without regard to a person’s routine. Apple has not explained this; Mac 911 columnist Glenn Fleishman thinks that it’s because a MacBook uses very little energy when not in use and the screen is dim, so the battery still charges to 100 percent. In that situation, Apple’s algorithm says charging to 100 percent is ideal–so little power is used that there aren’t big enough fluctuations in charging/discharging that would adversely affect battery viability.

Optimized Battery Charging is turned on by default, so there’s a good chance you’ve had it on for a considerable amount of time. If you don’t feel like it’s working, there’s a theory that the algorithm can’t learn when a MacBook is plugged in before turning it on. You may need to turn off the setting, unplug the power, restart the MacBook, turn it back on, and then plug the MacBook in to get the algorithm working.

In my experience, it doesn’t hurt to keep Optimized Battery Charging switched on whether you have a regular battery-use routine or not. My routine is irregular, and with the setting on, I’ve never had an instance where the battery wasn’t at 100 percent when I needed it to be.

How to adjust the Optimize Battery Charging setting

Accessing the Optimized Battery Charging setting isn’t obvious. Go to System Settings > Battery, and in the Battery Health section, click the Info icon (the “i” in the circle). A new window appears, and you’ll find a switch for Optimize Battery Charging. Apple turns it on by default, but if you want to turn it on or attempt to recalibrate it, you can do that here.

Note that you cannot set macOS to charge up to 80 percent and stop. You can’t do this on older iPhones, either, but you can do this with the iPhone 15 and iOS 17. Apple has never officially stated why this is. Perhaps it’ll change in a future macOS update.