Battery Monitor is a native Swift menu bar app for macOS battery, power, USB-C, and thermal diagnostics.
- Menu bar battery percentage, charging state, and detailed SwiftUI popover.
- Battery health, cycle count, design capacity, full-charge capacity, nominal capacity, estimated cycles to 80%, pack reserve, manufacture data, chemistry, gas gauge firmware, and lifetime temperature statistics.
- Compatibility with older top-level
AppleSmartBatteryproperties and newer nestedAppleSmartBatteryPack/BatteryDatalayouts seen on macOS 26 and 27. - USB-C Power Delivery diagnostics, charger capabilities, active contract data, adapter input power, and port controller details.
- General Thermals summary for current CPU, GPU, battery, memory, storage, PMU, enclosure, and system temperatures when exposed by the host.
- Thermals Advanced source groups with every collected temperature, pressure, source status, sensor identifier, classification, warning, and error.
- Optional root LaunchDaemon helper with native Swift AppleSMC, IOHID,
IOReport, AppleSmartBattery, IORegistry,
powermetrics, andpmsetcollectors without running the menu bar UI as root. - Signed and notarized DMG releases.
- macOS 13.0 Ventura or later.
- Swift 5.9 or later for source builds.
- Xcode or Xcode Command Line Tools.
- Apple Silicon is the primary tested target. Intel Macs may build and run, but
some Apple Silicon, USB-C Power Delivery, and
powermetricssamplers may not exist there.
Download the latest BatteryMonitor.dmg from
GitHub Releases.
The release DMG is signed, notarized, and includes an Applications symlink for
drag-and-drop installation.
After launching the app, use the visible Root Helper toggle to persist the privileged helper as a root LaunchDaemon. macOS may require admin approval in System Settings before the LaunchDaemon starts.
brew tap swack-tools/tap
brew install --cask battery-monitorgit clone https://github.com/swack-tools/battery-info-mac.git
cd battery-info-mac
swift build -c release --product BatteryMonitor
swift build -c release --product BatteryMonitorPrivilegedHelperRun the menu bar app from source:
swift run BatteryMonitorBuild a local DMG:
VERSION=dev just build-dmg
open .build/artifacts/BatteryMonitor.dmgThe menu bar app runs in the user session. The Root Helper toggle registers or unregisters a separate root LaunchDaemon that writes sanitized telemetry JSON to:
/Library/Application Support/BatteryMonitor/privileged-telemetry.json
Battery Monitor collects thermal data from:
- AppleSMC: decoded CPU, GPU, battery, and memory temperature keys.
- IOHID: Apple Silicon temperature events for battery, PMU, NAND/storage, enclosure, CPU, GPU, and other labeled sensors.
- IOReport: genuine Celsius thermal channels with source scan diagnostics.
- AppleSmartBattery and IOKit: current, virtual, and lifetime battery temperatures plus conservative registry thermal fallbacks.
ProcessInfo,pmset -g therm, and rootpowermetrics: system pressure, throttling, forced idle, power limits, and CPU/GPU/ANE/DRAM component power.
General Thermals chooses one representative current value per component and excludes lifetime aggregates. Thermals Advanced retains all valid readings and reports each source independently, so an unavailable private API does not hide data from other collectors.
Temperature bands:
- Battery: green below 40 C, orange from 40 C to below 45 C, red at 45 C or above.
- CPU/GPU/ANE/DRAM: green below 70 C, orange from 70 C to below 90 C, red at 90 C or above.
- Storage: green below 50 C, orange from 50 C to below 70 C, red at 70 C or above.
Throttling is shown as a percentage with nominal, light, moderate, or heavy status. The helper prefers explicit power-limit percentages, then SFI forced idle percentages, then thermal-pressure-derived estimates.
This repository uses just for common developer tasks:
just test # Swift tests
just lint # SwiftLint when installed, YAML parse, plist lint
just build-dmg # Build a local DMG in .build/artifacts
just run # Run the menu bar appThe local build-dmg recipe creates an unsigned DMG by default. Set
SIGN_IDENTITY to sign the app bundle locally:
SIGN_IDENTITY="Developer ID Application: Example (TEAMID)" just build-dmgReleases are built by .github/workflows/release.yml on macOS runners.
The workflow:
- Builds
BatteryMonitorandBatteryMonitorPrivilegedHelperin release mode. - Creates
BatteryMonitor.appwith the helper and LaunchDaemon plist bundled. - Signs the helper, main executable, and app bundle with the Developer ID certificate from repository secrets.
- Builds
BatteryMonitor.dmg. - Submits the DMG to Apple notarization, staples the ticket, and validates it.
- Generates a SHA-256 checksum.
- Creates the GitHub release, or updates an existing release and uploads DMG assets with clobber semantics.
Manual rebuilds are supported from GitHub Actions with a tag input such as
v1.1.0. This is useful when the release already exists but the assets need to
be rebuilt and uploaded again.
Sources/BatteryMonitor/ Menu bar app
Sources/BatteryMonitorShared/ Shared telemetry models and parsers
Sources/BatteryMonitorPrivilegedHelper/ Root helper executable
SupportFiles/ App metadata, icons, entitlements
SupportFiles/LaunchDaemons/ Bundled LaunchDaemon plist
Tests/BatteryMonitorTests/ Swift tests
Battery Monitor reads from:
- IOKit and IORegistry:
AppleSmartBattery,AppleSmartBatteryPack,AppleTypeCPortController,IODisplayConnect. system_profiler: battery firmware, charger details, hardware model.pmset: power settings, assertions, power source history, scheduled events, and thermal warning state.powermetrics: privileged component power, thermal pressure, power limits, and SFI forced-idle data through the root helper.
- The app reports current state only; it does not keep a time-series history.
- Some IORegistry keys are model and macOS-version dependent.
- The privileged helper requires admin approval and works best when the app is
installed in
/Applications. powermetricssampler availability varies by hardware and macOS version.- Release artifacts are built for Apple Silicon on GitHub-hosted macOS runners.
MIT