It measures your Mac’s power draw.
On battery, Pilot Light averages your whole Mac’s drain with the lid open and with it closed, and shows the hours of battery each works out to. You can see it working.
With one click on the flame in the menu bar, Pilot Light turns on. Close the lid and most Macs go to sleep; with Pilot Light the screen goes dark, Low Power Mode switches on and the Mac stays awake, so your agents keep working. Measured power falls from 16.7 watts with the lid open to 4.8 watts with it closed.
Lid shut. Pilot light on.
Close the lid and your MacBook burns down to a pilot light: dark, quiet and still working. Your agents keep going on under a third of the power1.
About 3.5× less power with the lid closed.1
The same Mac with the same apps open: 16.7 watts with the lid up, 4.8 with it shut. That’s the difference between an evening of battery and a night and the next day.
Lid open16.7 W · about 6 hours
Lid closed, Pilot Light on4.8 W · 20+ hours
0 h6 h12 h18 h24 h
Apps built on power assertions stop idle sleep. But a MacBook still sleeps the moment its lid closes. Pilot Light uses the setting that keeps it awake, then looks after the battery while it does.
Low Power Mode, then puts it back.
It switches to Low Power the moment the lid closes, and restores your exact battery and charger settings when it opens.
Logs out? It sleeps.
It keeps the Mac awake only while you’re logged in. Log out or switch users, and closing the lid puts the Mac to sleep as normal.
Heat and battery cutoffs.
With the lid closed, if macOS reports serious heat or the battery drops below your limit, the Mac goes to sleep anyway.
One admin prompt, tightly scoped.
The helper lets Pilot Light change only the sleep and Low Power settings, so it doesn’t need your password every time.
Specs and measurements.
- Memory
- ~25 MB20–31 MB measured while running
- Download
- 880 KBThe whole app, zipped, icon included
- CPU
- ~0%While waiting. It checks the lid and battery every 2 seconds and reads power every 30.
- Code
- One Swift file, 358 linesNo third-party code, no network requests
- Requirements
- macOS 13 or later2Apple silicon and Intel MacBooks
- Permissions
- One admin promptSleep and Low Power settings only
Set up in a minute.
- Download and drag to Applications.
It isn’t notarized yet, so the first time, right-click the app and choose Open.
- Click the flame, then Install helper.
One admin prompt. The flame turns solid when Pilot Light is on.
- Close the lid.
Screen off, Low Power on, and your agents keep running.
Or build it from source
git clone https://github.com/CyrisXD/pilot-light
cd pilot-light
./build.sh
open ~/Applications/"Pilot Light.app"Needs the Xcode command line tools. Builds a universal app for macOS 13 and later.
While Pilot Light is on, your Mac won’t idle-sleep with the lid open either. The screen still turns off.
Free. Kept lit by people like you.
Pilot Light is free and open source, with no ads, no account and nothing phoning home. If it’s kept your agents running overnight, you can help fund the next update.
GitHub Sponsors uses your GitHub account. Buy Me a Coffee works without one.