Take charge of your battery.

The macOS limit is a ceiling only, and it only goes from 80% to 100%. A ceiling parks the battery at the limit for as long as you stay plugged in, and time spent resting at a high charge level is what ages lithium-ion fastest. Apple’s own guidance for long-term storage is around 50%, a level the built-in limit can’t reach. Ampere holds a range instead: you choose both ends of the band, say 40 to 80%. Charging stays off while the battery drifts down to the lower bound, then runs one whole pass back to the upper. The battery lives at a lower average charge, in fewer, fuller cycles, in whatever band you choose. Set it once and stop thinking about the battery.

Apple Silicon Macs (M1 and later) running macOS 15 Sequoia or newer. On macOS 15, charge control depends on the firmware: if a security update has removed the key Ampere uses to stop a charge, Ampere monitors the battery only and says so, because macOS 15 has no charge limit to fall back on (see the technical page). macOS 14 isn’t supported, and neither are Intel Macs, which use different charge-control hardware.

Because macOS charged it. Every few weeks while a charge limit is in use, macOS charges the battery to 100% once, to keep its state-of-charge estimate accurate, and ignores the limit until that charge is over. It happens with the built-in charge limit too, and it cannot be stopped. On firmware without the CHTE key (macOS 27), that limit is what Ampere holds with, so the hold is overridden for the duration: the status line says so, and once the battery is full it says that macOS lifts the override within about 12 hours (macOS lifts it by the clock, about 12 hours after the charge began, not when the battery fills); the health check reads suspended, and the hold resumes where the charge ends; Discharge to Upper Bound brings the battery back to the bound. See macOS’s calibration charge.

Pausing and resuming charging requires writing to the SMC, which needs root. Ampere installs a minimal helper binary for exactly that, protected by a sudoers rule pinned to the helper’s SHA-256 digest — you’ll only be asked again when the helper itself changes. Other accounts on the same Mac are asked once each, because the rule keeps one line per account.

Everything Ampere changes is reversible, and reversal doesn’t depend on the app exiting cleanly. A detached watchdog daemon monitors the app and restores normal charging, discharge, and sleep settings within seconds if Ampere ever dies unexpectedly.

Quit Ampere, then drag it to the Trash or run brew uninstall ampere. Quitting puts charging and sleep settings back, and two minutes later a small root cleanup job that Ampere registers removes the helper, its sudoers rule, itself, and Ampere’s preferences and caches for every account, so nothing is left behind. If you delete the app while it is still running, the job waits until that copy quits and then does the same. To do it immediately, quit Ampere and run sudo /Library/PrivilegedHelperTools/az-ampere-smc purge.

Custom charge bounds. An unregistered copy has every other feature and holds the battery in the default 40 to 60% range; once registered, you can drag both bounds anywhere. If a registration lapses (the Mac is released from its key, say), the range goes back to the default until you register again.

Yes. A key registers up to … Macs at once, so a new Mac usually just registers with the same email and key beside the others. Once the key is full, another Mac is refused until you make room: deregister from the panel on a Mac you no longer use, or release a Mac that is gone under My Licenses at azcode.dev. A released Mac goes back to unregistered at its next check. My Licenses at azcode.dev and the app’s registration window show how many Macs your key is in use on, out of how many it registers.

Your keys are in the purchase email — and always available online: sign in at azcode.dev with the same email (no password needed, a login link is sent to you) and open My Licenses to see every key you own, copy it, and check which Macs it’s registered on.

If Ampere isn’t for you, tell us within 14 days of purchase for a full refund — sign in at azcode.dev with your purchase email and open a ticket. Refunded keys are deactivated.

No analytics, no tracking. Once registered, the app re-verifies your license about once a day and whenever you open its registration window (email, device serial, app version, and macOS version), and checks the Homebrew cask for updates. An unregistered copy contacts no license server at all. Network failures never deactivate a registration. The fine print lists everything the license server keeps.