Battery

Battery is a free, open-source charging limiter for Apple Silicon MacBook users who keep their laptop connected to power for long periods. It provides a menu bar application and installs an underlying command-line utility.

Charging controls

The standard app holds the battery near 80%: it can discharge toward that level even while plugged in, stop charging above it and resume below it. The limit remains active after closing the tray app and after rebooting. The CLI supports custom target percentages or ranges, charge and discharge commands, status reporting and calibration. A charge limit reduces available unplugged runtime; it is not a promise that every battery will have a particular lifespan.

Installation and hardware

Download the official Apple Silicon archive and install the app, or use brew install --cask battery. The exact 1.4.0 arm64 ZIP is 91,734,980 bytes, confirmed by HTTP HEAD against the official GitHub release asset. Unpacked application files and supporting components require more space. Open the app to complete setup: the official README states that it requests an administrator password to install its components and automatically installs the battery CLI. The separately documented CLI setup uses an SMC helper in /usr/local/bin.

The project explicitly supports Apple Silicon MacBooks and says it does not work on Intel Macs. The current cask likewise requires arm64. Read-only inspection of the exact 1.4.0 archive confirms the main battery executable is arm64 and its Mach-O build command targets macOS 11.0 or later. Its Info.plist says 10.15, which is not a claim that an Apple Silicon MacBook runs macOS 10.15. These are main-app startup declarations, not a guarantee that every SMC helper or charging feature works on every later macOS release. The checked official README does not publish a separate complete helper/feature OS compatibility range or numeric minimum RAM. No named cask conflict is declared, but do not run competing charging controllers without testing how their settings interact.

Permissions, privacy and network

Administrator authorization changes charging behavior through helper components. The checked README does not establish a requirement for blanket Accessibility, Screen Recording or Full Disk Access. No cloud account or subscription is required. Downloads and updates need internet access; the installed charging control is local. The README discloses calls to GitHub and the Electron update service, an internet connectivity check at icanhazip.com, and installation analytics at unidentifiedanalytics.web.app that counts unique IP addresses. Treat this as a developer disclosure rather than an independent privacy audit. Blocking network endpoints can prevent updates.

License and safety

The repository uses the MIT license, with no license purchase required. Charging limits persist independently of the open menu bar window; closing the app does not restore normal charging. Before travel, explicitly stop maintenance or change the limit and verify the reported state. Calibration deliberately discharges and recharges the battery, so plan it when power and time are available. The official 1.3.2 notes describe a prior GUI bug that could drain the battery until the utility was restarted; use a current release and inspect charging status after updates. Uninstalling through the CLI is documented to enable charging and remove the helper and script, whereas merely deleting the app may not clear every installed component.

Sources: Official project and usage guide, Official releases, MIT license.