After facing questions over the long-term performance of its devices’ rechargeable batteries, Apple tweaked its iOS operating system to give users more control over the way iPhones performed as their batteries aged. Now the company is turning its attention to MacBook batteries with a related change to macOS Catalina 10.15.5, which is available now in beta form for developers and the general public.
Historically, users haven’t had many options when recharging a MacBook: Plug it in, open Energy Saver settings to specify when the screen and hard disks should go to sleep, and forget about it. Now Apple is adding Battery Health Management (via SixColors) as an additional checkbox within Energy Saver, letting users determine how they’d like the laptop’s recharging system to work. Turned on, Health Management will stop charging below the battery’s 100% mark. Turned off, the machine will fill all the way up, just as it did in the past.
If this sounds crazy — who would want to leave home with a less than fully charged laptop? — there’s a method to the madness. Keeping any rechargeable battery constantly at 100% is akin to keeping a faucet constantly running just a little to compensate for a bathtub’s daily water evaporation, which would be wasteful. For a laptop battery, this constant trickle-up-to-100% process actually winds up wearing out the battery, in some cases for no good reason. The new option lets users put less stress on the battery by keeping it filled to a safe and entirely usable level by default, only pushing it to peak capacity when the user specifically needs it.
On iPhones, Apple calls a similar feature “Optimized Battery Charging,” and provides an on-off switch for it within iOS’s Battery > Battery Health settings. There, the company says the “iPhone learns from your daily charging routine so it can wait to finish charging past 80% until you need to use it,” suggesting that machine learning is helping to make the decisions. Here, the macOS system apparently just lets users make their own determinations on when they do and don’t need full charges.
Battery Health Management will be available for MacBooks with Thunderbolt 3 ports, including MacBook Air models with Retina displays, as well as 2016 and newer MacBook Pros. The feature does not appear to include the granular battery health details or charts that were added to iOS for the iPhone, leaving room for some improved future disclosures of the battery’s current maximum capacity and last 10 days of charge cycles.