Many MacBook Air, MacBook Pro, and MacBook Neo owners have noticed something curious; their MacBook battery stops charging at 80% when plugged in. To add to the confusion, even if they leave their MacBook plugged in overnight, the battery seems to be stuck at 80% and will not charge any further. Because this is not necessarily understood or expected behavior, some Mac users think there may be something wrong with their battery or their computer.
So what’s going on here? Why is the MacBook battery stuck at 80% and will not charge more? It turns out this is intentional behavior, part of a feature of MacOS that is designed to help preserve long-term battery health on your MacBook. Let’s explain, explore this further, and learn how you can fully charge the MacBook to 100% at any time, and even how to change this setting so it always charges to maximum capacity.
Why the MacBook Stops Charging at 80%
Why the battery stops charging at 80% is due to a feature called Optimized Battery Charging. This MacOS feature uses machine learning to learn your computer usage and routine, and pauses charging at 80% when it predicts the MacBook will be plugged in for a long period of time, to reduce chemical aging of the battery itself.
Modern laptop batteries age faster when kept at 100% charge for long periods of time, especially when they’re plugged in to a power source constantly. Therefore, to reduce wear on the battery, MacOS will intentionally pause charging around 80%. After the Mac has learned your charging and battery habits, it will attempt to finish charging closer to when it thinks you’ll actually be unplugging the Mac and running exclusively on battery power.
For example, if you routinely charge your MacBook overnight, but disconnect it in the morning to head off on your day, MacOS will learn this schedule and keep the battery at 80% until the morning, when it will then charge to 100% on its own.
Understandably, this feature can catch a lot of MacBook Pro, MacBook Neo, and MacBook Air users off guard, as it appears the battery just stops charging at 80% or that it won’t go beyond that, even if it’s plugged in. But in most cases, the system is doing exactly what it was designed to do, which is to limit a full charge until it’s needed.
How to Charge MacBook Battery to 100% at Any Time
The absolute simplest way to override the Optimized Battery Charging feature at any time, is do the following:
- Connect the MacBook to a charger if you have not done so already
- Pull down the Battery menu from anywhere in MacOS
- Choose “Charge to Full Now”
The battery on the MacBook Air, MacBook Pro, or MacBook Neo will now charge fully to 100%.
You can do this at any time to get a full 100% charge on the battery, regardless of whatever the Optimized Battery Charging feature has learned about your Mac usage and whatever other settings are in place.
Personally I use this “Charge to Full Now” feature somewhat regularly, because my MacBook Air battery usage is somewhat random and MacOS has not figured it out yet (neither have I for that matter, I use my laptop as a laptop and on the go quite often so there’s not always a defined schedule). I keep the setting enabled, but just manually override it with some regularity using the method just described.
How to Disable or Change Optimized Battery Charging on Mac
If you’d like to change this behavior and have the Mac not try to optimize your battery charging or preserve the lifespan of your battery, you can disable the feature. You can also change the setting from 80% to 90% or another battery percentage limit you prefer to rest at.
- From the Apple menu go to “System Settings”
- Go to “Battery”
- Click on the little (i) button next to “Charging”
- To turn off the feature, toggle the switch for “Optimized Battery Charging” to the OFF position
- Alternatively, adjust the slider to the desired battery charge limit
Remember, MacOS defaults to keeping this features enabled for a reason; it can help protect battery lifespan on your Mac. Keeping a battery charged at 100% all the time can create more physical stress on the battery and reduce it’s functional lifespan, so letting MacOS manage the charge limit and charging on its own is generally a wise decision.
Are there any other reasons why the MacBook battery won’t charge fully?
While the Optimized Battery Charging feature is the number one reason a MacBook battery will stay at 80% or stop charging there, there are other possible explanations as well.
If the MacBook Air, MacBook Pro, or MacBook Neo is older, has significant heat exposure, or has been used considerably with heavy battery wear, the battery itself will degrade. As a battery degrades it’s maximum charge and capacity will degrade as well, and it’s possible that a heavily used or damaged battery health has degraded to such a point that it is no longer capable of holding a 100% charge.
Related, some Mac users have noticed their MacBook screen dims automatically when on battery and have wondered if that’s a related problem, but that’s also just a feature of MacOS designed to prolong battery life. You can adjust or turn that off too if you’d like.
Checking your MacBook battery health
You can check your MacBook battery health at any time from System Settings by going to Apple menu > System Settings > Battery > Battery Health.
This works the same on all modern MacBook Pro, MacBook Air, and MacBook Neo, with any modern version of MacOS.
Remember, for most users the MacBook battery stopping charging at 80% is normal expected behavior, as part of Apple’s built-in battery preservation system. It might seem a little weird at first, and could be disconcerting if you do not understand what it’s doing and why, but rest assured, it’s part of MacOS and it’s usually intentional behavior. If need be, remember you can always manually override at any time, and charge your battery to 100% just by using the battery menu item on your Mac.
So the next time you or someone else finds their MacBook battery won’t charge past 80%, remember it’s the battery optimization feature, and it’s generally good for your Mac, and easy to override if need be.
