How to use

Three steps from install

Create one shortcut once, then switch the charge limit any time from the menu bar.

Download & launch

Grab the DMG from GitHub Releases, copy the app to your Applications folder and launch it. Your battery level appears in the menu bar.
Create one shortcut

Follow the in-app setup guide to build a shortcut using Apple's built-in "Set Battery Charge Limit" action (about a minute). Because the action is Apple's own, the app holds no privileges at all.
Pick a limit

Choose 80 / 85 / 90 / 95 / 100% from the menu bar. macOS itself then manages charging safely — stopping at the limit and recharging after a 5% drop.

Features

Lightweight, safe, always resident

The app never turns charging on or off itself — every control is delegated to macOS's native mechanism.

Native charge limit: Sets Apple's built-in charge limit (80–100%), introduced with macOS 26.4, through the official Shortcuts action. No private APIs, no privileged daemon.
Menu bar resident, Dock-hidden: Battery level and charging state live in the menu bar. The app never shows up in the Dock.
Lightweight by design: One resident process. Power state is watched through event-driven IOKit notifications instead of busy polling.
Crash safety: No force unwraps, every external call is time-bounded. If anything fails, the app degrades to a read-only monitoring mode instead of breaking.
Safe fail behavior: If the app quits or crashes, the limit stays enforced by the OS — your Mac always remains under Apple's standard charging management.
Battery health: Cycle count and maximum capacity (versus design) in the diagnostics window, one click to copy for issue reports.
Charge to 100% now: Need a full charge before leaving? One menu click temporarily sets the limit to 100%.
Launch at login: Registers itself with SMAppService so it is always running after login (toggle from the menu).
日本語 / English: The UI is fully localized in Japanese and English (follows the system language).

Requirements & build

◆ macOS 26.4+ (macOS 27 / Golden Gate supported) · Apple Silicon Mac with an internal battery
◆ Charge limit control uses the built-in "Set Battery Charge Limit" Shortcuts action (macOS 26.4+)
◆ Ad-hoc signed (not notarized). Allow the first launch under System Settings › Privacy & Security

git clone https://github.com/oriyu90/save-battery
cd save-battery
swift build && swift test
scripts/build-app.sh