Batt – macOS Tahoe menu bar power app

This is a macOS 26 (Tahoe) menu bar application that shows:

• When charging
  • Battery % of capacity
  • Time until full (h:mm)
• When discharging
  • Battery % of capacity
  • Time until empty (h:mm)
• On click (popover)
  • Power adapter (e.g. 65 W)
  • Charging watts (e.g. 49.5 W)
  • Current consumption (e.g. 15 W)

The implementation is written in Swift + SwiftUI and uses:

• IOPowerSources (IOKit) for battery percentage, charging state, and time to full/empty
• PowerTelemetryData from IORegistry (via ioreg) for adapter wattage and live power metrics on Tahoe

Note: Wattage / telemetry values come from undocumented IORegistry fields and may not be available on all hardware. The UI falls back to — where a value is missing.

Download

Grab the latest Batt.zip from the Releases page, unzip it, and drag Batt.app to your /Applications/ folder.

Because Batt is not notarized (Apple charges $99/year for the privilege of not showing this error), macOS will show a "damaged" error when you try to open it. To fix this, open Terminal and run:

xattr -cr /Applications/Batt.app

Then open the app normally. You only need to do this once.

Building an installable app (Swift Package Manager)

To produce a standalone Batt.app bundle:

./package_app.sh

This builds the app and creates build/Batt.app. To install:

cp -r build/Batt.app /Applications/

Launch at login

Batt includes a "Launch at login" toggle in the popover. When enabled, the app will start automatically when you log in. The first time you enable it, macOS may prompt you to approve in System Settings → General → Login Items.