Voltway Charge Helper

An optional download that lets Voltway control charging on your Mac.

You do not need this to use Voltway. The power-flow diagram, the battery forensics and the history all work without it. The helper only adds charge control.

It is a root background daemon, not a one-off password prompt. Once installed it runs as root, starts at every boot, stays resident, and listens on your Mac's loopback interface. The section below sets out exactly what gets installed and why it has to work that way — read it before you decide.

Why is it a separate download?

Limiting charge means writing to your Mac's System Management Controller — the chip that actually runs the charger. That requires administrator privileges, and Mac App Store apps are not permitted to request them (App Store Review Guideline 2.4.5(v)).

So rather than ask for privileges it is not allowed to have, Voltway keeps that work in a small, separate program that you install yourself and can remove at any time. The App Store app never escalates and never installs anything.

This helper is not part of the Mac App Store app and does not come from the App Store. It is a separate download from this page, signed with an Apple Developer ID certificate and notarized by Apple.

What it does

Holds your battery at a limit you choose, including limits below 80%
Separate upper and lower thresholds, so the pack is not constantly topped up
Runs your Mac from the adapter without charging, or from the battery while plugged in

What actually gets installed

Three things, and it is worth knowing exactly what they are before you run the installer:

/usr/local/libexec/voltway/VoltwayChargeHelper — the helper itself, owned by root:wheel, mode 755.
/Library/LaunchDaemons/com.mwsupplylimited.voltway.chargehelper.plist — the launchd job that starts it.
/Library/Logs/Voltway/ — its log files. Your chosen limit is saved separately in /Library/Application Support/Voltway/policy.json.

It runs as root, continuously, from every boot

The launchd job is a system daemon marked RunAtLoad and KeepAlive. In plain terms: macOS starts the helper as root when your Mac boots, before anyone logs in, keeps it running whether or not Voltway is open, and restarts it if it ever exits. Installing it is not a one-time elevation that ends when the installer closes — it is a permanent, privileged background process, and it stays until you remove it.

It listens on 127.0.0.1

The helper runs a small HTTP control server bound to 127.0.0.1 port 53845 — your Mac's own loopback interface, and nothing else. It is never bound to a network-facing address, so nothing outside your Mac can reach it. This is how a sandboxed App Store app, which has no privileges of its own, asks a privileged process to change a setting. The trade-off is stated plainly: any program already running as you on this Mac can also talk to that socket and change the charge limit. It cannot do anything else through it, and the safety limits below still apply.

Why it has to be that way

The charge limit lives in registers on your Mac's power controller, and those registers do not survive a power cycle. If the helper only ran while Voltway was open, your limit would quietly vanish every time you shut down, and would not come back until you next launched the app — which is exactly the failure people report with charge limiters that do not run at boot. Running at boot is what makes the limit mean anything. Running as root is what makes writing to the power controller possible at all: there is no unprivileged API for it, on any Mac.

How it keeps your Mac safe

This program can stop a Mac charging, so it is built to fail in the safe direction:

It writes the safe state first every time it starts, before reading any of your settings. A crash and restart can never leave you unable to charge.
If Voltway stops talking to it for more than a few seconds, it releases the limit by itself.
If the battery falls below 20%, or the pack goes outside 0–45 °C, it opens the gate regardless of your settings.
It restores normal charging on quit, on shutdown, and even if it crashes.
If it cannot reach Voltway at all, it leaves charging on rather than holding a limit nobody can release.

Requirements

A Mac notebook with Apple silicon, running macOS 14 or later
An administrator password at install time (macOS asks, not Voltway)
Willingness to run a permanent root background process — see what actually gets installed above

Some Macs do not expose a charge-control interface at all. Voltway detects this and tells you plainly rather than pretending the setting worked.

Install

Download Voltway Charge Helper 1.1

161 KB · macOS 14 or later, Apple silicon

Open the downloaded .pkg and follow the installer. macOS will ask for your administrator password — that prompt comes from the system installer, not from Voltway, and it is what allows the helper to be installed as a root daemon.

Signed with a Developer ID certificate and notarized by Apple, so Gatekeeper will open it without warnings. If you want to confirm you got the same file we published, check its SHA-256 before opening it:

shasum -a 256 ~/Downloads/VoltwayChargeHelper.pkg

It should print:
ad6f18aedec9a1925c6d18c3b0e6a54532f39178625434614099057a69adb255

What changed in 1.1

Running on the adapter without charging no longer cycles the charger. Once it reached your lower limit it would let the pack charge again, then immediately drain it — on and off every few minutes, indefinitely. It now holds steady at the limit.
It no longer keeps draining while your Mac is asleep. The safety checks that stop a discharge at 20% cannot run while the machine is asleep, so the helper now hands charging back before sleeping instead of continuing to run the Mac off its battery.
Uninstalling can no longer remove the helper before charging is confirmed normal. If it cannot verify that the charger was released, it now stops and leaves everything in place instead of deleting itself.
Only Voltway can change your charge settings. The helper now verifies the code signature of whatever is talking to it, so another program on your Mac cannot alter your charge limit. Releasing the charger is still unrestricted — that direction can only ever help.

If you already have 1.0 installed, download and open the new package — it upgrades in place and keeps your settings.

Remove it

Run this in Terminal:

sudo voltway-helper-uninstall

It stops the daemon first, then restores normal charging and reads the setting back to confirm the charger really was released. Only once that check passes does it delete the helper, its launchd job, its log directory, your saved limit and the uninstaller itself. After it finishes, no Voltway process runs as root on your Mac and nothing of it is left behind — you do not need to clean up anything by hand.

If that read-back ever fails it deletes nothing. Removing the helper while the charger is still held would leave you unable to charge with nothing on the Mac able to release it, so instead it puts the helper back — it keeps retrying on its own — and asks you to run the command again. The fallback beyond that does not depend on our software at all: the charge-limit registers are cleared by a power cycle, so shutting down fully and starting up again returns the charger to normal.

Contact

mwsupplylimited@gmail.com