Why your Mac still charges to 100%

You set a charge limit, and one morning the battery reads 100%. Usually nothing is broken. macOS has a few reasons to fill the battery, and most of them are on purpose.

macOS calibrates the battery

Apple says that whatever your settings, a Mac will occasionally charge to 100% to keep its estimates of the battery’s charge accurate. This happens with the Charge Limit in macOS and with apps that limit charging.

When it happens with BatFi, BatFi shows “macOS is charging to 100%”. It steps aside while the battery fills, and the battery goes back down to your limit afterwards. You don’t need to do anything.

Someone chose Charge to Full Now

When the Mac is held at its limit, the battery menu offers Charge to Full Now. It fills the battery once, for example before a flight. If you or someone else chose it, the Mac charged to 100% on request.

BatFi has the same one-time override, called Charge to 100%. Once the charge completes, BatFi goes back to your limit, and the battery returns to it as you use the Mac.

Optimized Battery Charging only delays the charge

Optimized Battery Charging learns your daily charging routine. When it expects the Mac to stay plugged in for a long time, it can hold the charge at 80% and show “Charging On Hold” in the battery menu. It still aims to have the Mac fully charged by the time it expects you to need it.

So with Optimized Battery Charging alone, a Mac that stays on the charger will reach 100%, only later. For a fixed ceiling you need a Charge Limit, either the one in macOS or an app.

Your Mac or macOS doesn’t have Charge Limit

The Charge Limit in System Settings needs macOS Tahoe 26.4 or later and a Mac with Apple silicon. An Intel Mac, or a Mac on an earlier version of macOS, has only Optimized Battery Charging, which means it eventually charges to full.

To check, open System Settings, click Battery, then the info button next to Charging. If there is no Charge Limit there, your Mac doesn’t have it.

Your charge limit app is out of date

macOS 27 changed the way charging is controlled. Apps written for earlier versions may stop limiting the charge, and the Mac charges to 100% as if no app were running. BatFi needs version 4.0 or newer on macOS 27. Older versions can also show 0% battery or get stuck on “Initializing”.

Installing the macOS 27 beta updates the battery’s firmware, and that change stays even if you go back to an older macOS. If you tried the beta, update BatFi to 4.0 or newer as well.

Two systems manage the same battery

If you use a charge limit app, turn off the Charge Limit in macOS and Optimized Battery Charging. With two systems managing the same battery, the Mac can stop charging below your limit, or the MagSafe light can turn green early, because macOS decided on its own that charging is finished.

Charging resumes after a drop

With the Charge Limit in macOS, charging starts again if the charge falls by more than 5% while the Mac is plugged in. This brings the battery back up to the limit. If you see charging start at your limit, this is the reason.