macjuice

MacJuice is a free Mac app that lives in your menu bar and shows detailed information about your laptop's battery, similar to what paid apps like coconutBattery offer, but running entirely on your own machine with no cloud account needed. It shows a live number next to a bolt icon in the menu bar, either battery percentage, power draw in watts, or both, depending on how you set it up.

Clicking that menu bar icon opens a small floating panel with much more detail: your current charge percentage, how long until the battery is empty or full, the temperature of the battery, its health as both Apple's official percentage and a raw capacity number, how many charge cycles it has been through, and how much power is currently flowing in or out. It also draws history charts of your charge level, power draw, and battery health over the last day, week, month, or all time, so you can see trends rather than just a single snapshot.

The app also keeps track of individual charging and discharging sessions, showing things like how long a charge took and what percentage it went from and to, and can estimate your remaining battery runtime based on how you have actually been using the laptop recently. A small popup notification briefly appears near the notch when you plug in, when Low Power Mode turns on, or when the battery gets low, then disappears after a few seconds.

MacJuice can also toggle macOS's Low Power Mode directly from its menu, using either a passwordless method through the Shortcuts app or, as a fallback, the normal admin password prompt. All battery data is read directly from the operating system and stored locally in a small SQLite database rather than sent anywhere, and the app is designed to use very little memory and almost no CPU in the background. It requires macOS 15 or newer, runs on Apple Silicon Macs, and can be installed either through Homebrew or by building it from source using Xcode's command line tools.