Find the activity behind the drain. Plan your time away from a charger.
Understand how your MacBook's battery changes over time.
Free, open-source battery monitoring with a native menu bar app and a local dashboard.
App energy estimates. Runtime forecasts. Battery health history.
No account. No cloud service. No subscription.
Install batmon · Explore the features · Privacy · GPL-3.0
Choose a 10%, 20% or 30% reserve, set how long you need to keep going, and compare your goal with a runtime range based on recent battery use. Keep charge and power in your menu bar; open the dashboard when you want the full picture.
The estimate adapts to your recent load. It pauses on AC and waits for enough continuous battery readings before making a prediction.
Explore a searchable app activity ranking, CPU/GPU/Neural Engine power, and charge history on a shared timeline. In the recent 24-hour view, filter app estimates by battery or AC to see how the picture changes away from your desk.
Then try one change. The Advisor walks you through a before/after experiment, checks measurement coverage and brightness, and compares observed power under the conditions you control.
See the macOS battery assessment alongside raw capacity trends, weekly medians and cycle history. Review time spent at higher charge levels, recurring events and changes between equal 7-day or 30-day windows.
The Health view also checks short-term capacity predictions against later historical readings. You can see how well a model performed before putting weight on its forecast.
Useful numbers, with their meaning attached. App energy is an estimate of chip activity, not a direct measurement of an app's share of the whole battery. Missing readings stay unknown. An unreliable long-term forecast stays withheld.
Nine focused views take you from a quick glance to a deeper investigation.
| View | What you can do |
|---|---|
| Now | Check charge, power, available sensors, your reserve and runtime goal. |
| Advisor | Choose autonomy or battery care, track completed actions and compare a change. |
| History | Align charge, power and temperature with a shared cursor, including keyboard control. |
| Apps | Search estimated chip-energy rankings and explore recent battery/AC differences. |
| Energy | Compare energy in and out, daily usage and how much time was actually observed. |
| Health | Separate macOS health from raw sensor trends; inspect shifts and forecast accuracy. |
| Charging | Review charging and holding periods, charge-level exposure and low-charge episodes. |
| Anomalies | Group recurring observations, inspect their evidence and acknowledge what you reviewed. |
| Report | Compare weeks or months, export JSON/CSV, or print through your browser. |
A Keep awake switch is there for long-running work. It prevents idle sleep while leaving lid-close and manual sleep behavior intact. Native charge-limit status appears when macOS exposes it; Battery settings are one click away.
Built for Apple Silicon MacBooks. Developed and checked on a MacBook Pro M4 Pro, including macOS 26.5 and 27.0. Other Apple Silicon/macOS combinations may expose different sensors and have not all been validated. Intel Macs are not supported.
You need Git, a working python3 with venv and pip, and Apple's Command Line Tools Python at /usr/bin/python3 for the collector. If Command Line Tools are missing, run xcode-select --install and finish Apple's installer first.
git clone https://github.com/m1l0rdz/batmon.git
cd batmon
./install.shRun the installer as your normal user. It requests administrator access for the system collector, installs Python dependencies in a local virtual environment, and starts the collector, web service and menu bar app.
Open 127.0.0.1:8899 and you're in. Keep the cloned folder in place: the web service and menu bar app run from it.
- Open Now. Check the first readings and choose your reserve.
- Use your Mac normally. A runtime range needs at least five minutes of continuous, usable battery observations.
- Explore Apps and History. Longer-range summaries appear after completed collection hours; health trends build with daily readings.
- Return to Report. Compare your own usage over time, with collection coverage shown beside the totals.
Updating and uninstalling
To update an unmodified checkout, pull the latest code and rerun the installer. Your history stays in the local database.
git pull --ff-only
./install.shTo remove the background services and installed collector while keeping your history:
./uninstall.shTo also permanently delete the collected history, use ./uninstall.sh --purge instead. The cloned project folder and its virtual environment remain in place.
Trying batmon on another Apple Silicon MacBook? Share a compatibility report. Include your Mac model and chip, macOS version, whether installation succeeded, and any missing readings. A successful install is useful feedback too.
If something fails, include the error message and what you expected to happen. Review logs and screenshots for personal information before sharing; you do not need to upload your battery database.
Your battery history belongs on your Mac.
- Local storage. Measurements stay in SQLite. There is no account, cloud backend or usage analytics service.
- Local access. The dashboard listens on
127.0.0.1, not your network interface. Its scripts, charts and fonts need no CDN. - A narrow collector. The privileged process uses macOS tools and opens no network sockets. The dashboard reads the database without writing to it.
- Your choices stay yours. Goals, the action journal and event acknowledgements are stored in your browser. They do not silently change macOS settings.
Installation downloads Python dependencies. Optional guidance links open external websites; collected telemetry is not uploaded by batmon.
How the measurements work
| Signal | Collection and scope |
|---|---|
| Battery charge, current and voltage | ioreg readings approximately every 15 seconds. |
| Chip and app activity | A short powermetrics sample each minute; app energy is allocated from relative Energy Impact. |
| Battery condition | The macOS assessment, shown separately from the raw capacity/design ratio. |
| History | Raw samples for 48 hours, hourly summaries for 90 days, daily summaries retained indefinitely. |
Recent app source filters use estimated time alignment. Historical app summaries combine AC and battery. Chip and battery readings have different sampling intervals, so their difference cannot identify display, Wi-Fi or SSD consumption.
The habits score describes available charging observations, not battery health or remaining lifespan. Before/after comparisons are observational; workload and other unmeasured conditions can still explain a change.
Data is stored at /usr/local/var/batmon/batmon.db. The stack is Python, FastAPI, SQLite, a native rumps menu bar app and a vanilla JavaScript dashboard with bundled Chart.js.
If a reading or export is unavailable
- Missing temperature or charge limit: sensor and policy availability varies with macOS and hardware. Unavailable values are not treated as zero.
- No runtime yet: use battery power and allow at least five uninterrupted minutes of usable observations. Sleep gaps or a change of power source restart the window.
- No long-term forecast: enough stable history is required. An observed trend can still be shown without extrapolating it into a replacement date.
- An embedded browser does not download: JSON and CSV exports include a readable preview and a Copy data button. For Print / Save as PDF, use a browser that supports printing, such as Safari or Chrome.
- Dashboard does not open: check
~/Library/Logs/batmon/batmon-web.logand/usr/local/var/batmon/batmond.out.log, then report the error with your Mac model and macOS version. Review logs before sharing them.
Make your next battery decision with a little more clarity.
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