Inside ChargeLens: Every Battery on the Desk, One Click Away

ChargeLens is a small Mac utility from 1dot1 that answers two everyday questions from the menu bar: how is the Mac battery really doing, and which of the things around it is about to go flat. One click opens a single panel with the Mac’s charge and health at the top and every connected Bluetooth device underneath. This teardown walks through it screen by screen and explains the decisions behind each part.

The information is not secret. macOS already knows the cycle count, the capacity of the battery when new and the level of a Magic Keyboard. It is simply spread across System Settings, System Information and the Bluetooth menu, some of it several clicks deep, and none of it warns anyone before a mouse dies in the middle of a call. ChargeLens gathers it in one place, reads it without asking for special permissions, and keeps all of it on the Mac.

One click, the whole picture

The menu bar icon is a battery with a pulse line through it. Clicking it opens the panel under the menu bar. The top shows the charge as a large number beside a battery gauge, with a single word for the state: charging, on battery, or plugged in but holding its charge. That last state matters more than it sounds. A Mac on power that is not charging looks like a fault, but it is usually macOS protecting the battery, and saying so plainly avoids a worried trip to a forum.

Below the charge come six figures in a grid, then the last 24 hours, then the device list, then a footer with the time of the last update and the current alert levels. The order follows how often each part is needed. The charge is glanced at daily, the device list when something stops responding, and the history now and then. A refresh button and an ellipsis menu sit in the header, and nothing else competes for space.

Health, not guesswork

Battery health is where most apps get vague, so ChargeLens shows its working. Health is the battery’s full-charge capacity as a share of its original design capacity. The small line under the grid gives both figures in mAh, for example 5,650 mAh when full against 6,075 mAh when new. Anyone who wants to check the percentage can do the sum. On a test Mac the result matched the Maximum Capacity that System Information reports.

Cycles is the cycle count straight from the battery. Condition reads Normal, or Service recommended when health drops under 80% or macOS itself flags the battery. Power shows the adapter wattage when one is connected, which is a quick way to spot a weak charger. Time shows how long until empty or full once macOS has an estimate, and stays blank until then rather than inventing a number. Temperature is the battery’s own sensor reading.

A Mac mini or iMac has no internal battery, and ChargeLens says so in place of the figures. The rest of the panel carries on working, because a desktop Mac is exactly where a wireless keyboard and trackpad live.

Every battery in one place

The Devices list shows every connected Bluetooth device. AirPods get a line of their own for left, right and case whenever they report them, because the single number macOS often shows hides the fact that one bud is nearly empty. The case usually reports only while it is open or a bud is inside, which is a limit of the hardware rather than the app. AirPods levels come from System Information, which updates every few minutes, so a reading can trail the real level briefly.

Magic Keyboard, Magic Mouse, Magic Trackpad and other accessories that share a level get a percentage and a small gauge, and a device running low carries a LOW badge. The most important design decision is the last row in the screenshot. A speaker that does not share its battery says not reported. ChargeLens never estimates a level it has not been given, so every percentage on screen is one the device actually sent.

The list refreshes on its own, and the circular arrow at the top of the panel refreshes it straight away. A device that has gone to sleep drops off the list until it is woken, since only connected devices can be read.

A nudge before it goes flat

Numbers in a panel only help if someone looks at them, so ChargeLens can also say something first. Low Battery Alert lives in the ellipsis menu, with a choice of 10%, 15%, 20%, 25% or 30%, or Off. The default is 20%. When any device, or the Mac while on battery, falls to that level, one notification appears.

The rule behind it is once per drop. The alert does not repeat as the level falls further, and it does not come back until that battery has been charged above the level again. A keyboard at 12% is worth one reminder, not one every few minutes, and a notification that nags is a notification that gets turned off. For the same reason every notification is silent.

Full Charge Reminder works the other way round. Pick a level from 80% to 100%, or Off, and one notification appears when the Mac reaches it while plugged in, as a prompt to unplug for anyone who prefers to keep the charge topped up only so far. macOS Optimised Battery Charging can hold the charge below the chosen level, in which case a lower level such as 80% is the one to pick.

The last 24 hours at a glance

Last 24 hours charts the Mac’s charge level across the day, with the range printed in the corner. A bar along the bottom marks the time spent charging, so a long slope down followed by a flat line reads at once as a working day and then a desk with the adapter plugged in.

ChargeLens notes the level every five minutes while it is running and keeps a week of readings. Gaps in the line are deliberate. They mark times the Mac was asleep or the app was not running, and joining the dots across them would draw a discharge that never happened. The readings are a small file at ~/Library/Application Support/ChargeLens/history.json, readable in any text editor. A new install starts with an empty chart that fills in as readings are taken.

Right there in the menu bar

Menu Bar Shows has three settings. Icon Only keeps the menu bar quiet. Mac Battery % puts the Mac’s charge beside the icon. Lowest Device % follows whichever device is running lowest, which turns the menu bar into an early warning for the whole desk: a 12% there means something needs a cable, and the panel says what.

A right-click on the icon offers Refresh Now, Open at Login, About and Quit, so the common housekeeping never needs the panel. Open at Login keeps ChargeLens in the menu bar from the moment the Mac starts, which is also what keeps the history chart free of gaps.

Built in black and white

Like the other 1dot1 Mac apps, ChargeLens is greyscale. The icon is a black battery with a white pulse line, and the menu bar glyph repeats it at a smaller size. Inside the panel, figures are set large and labels small and grey, gauges are simple outlines filled in proportion to the charge, and the only emphasis is the LOW badge. With no colour to lean on, a level has to be readable from the number and the gauge alone.

It is a universal app for Apple silicon and Intel Macs, runs on macOS 13 Ventura or later, and needs no special permissions. It reads the battery information macOS already publishes and the list of Bluetooth devices from System Information. The only prompt is the standard one for notifications. Nothing is uploaded, there is no account, and the app never connects to the internet.

How to use it, feature by feature

The same instructions are in the short PDF inside the download.

Installing it

1. Unzip the download and drag ChargeLens.app into the Applications folder, then open it. A battery icon with a pulse line appears in the menu bar.
2. ChargeLens is signed and notarized by Apple, so it opens with a normal double-click.

Reading the Mac battery

1. Click the menu bar icon. The top of the panel shows the charge and whether the Mac is charging, on battery, or plugged in but holding its charge.
2. Health is full-charge capacity as a share of design capacity; the line under the grid shows both in mAh.
3. Cycles is the cycle count. Condition reads Normal, or Service recommended under 80% health or when macOS flags the battery.
4. Power shows adapter wattage when connected, Time shows how long until empty or full once macOS has an estimate, and Temperature is the battery sensor reading.
5. A Mac with no battery shows No internal battery instead; the device list still works.

Checking device batteries

1. Look at the Devices list for every connected Bluetooth device.
2. AirPods show left, right and case separately whenever they report them. The case usually reports only while open or with a bud inside.
3. Keyboards, mice, trackpads and other accessories that report a level show a percentage and a small gauge.
4. A device that does not share its level says not reported.
5. Press the circular arrow at the top of the panel to refresh straight away.

Setting alerts

1. Open the ellipsis menu, then Low Battery Alert, and pick 10% to 30%, or Off. The default is 20%.
2. When any device, or the Mac on battery, falls to that level, one notification appears. It will not repeat until the battery is charged back above the level.
3. Open Full Charge Reminder and pick 80% to 100%, or Off, for one notification when the Mac reaches that level while plugged in.
4. Notifications are silent. The first time, macOS asks whether ChargeLens may show them.

Reading the history

1. Last 24 hours charts the Mac charge level, with a bar along the bottom for time spent charging.
2. Readings are taken every five minutes while ChargeLens runs, and a week is kept.
3. Gaps are times the Mac was asleep or the app was not running.
4. The readings live at ~/Library/Application Support/ChargeLens/history.json.

Setting up the menu bar

1. Open the ellipsis menu, then Menu Bar Shows, and pick Icon Only, Mac Battery %, or Lowest Device %.
2. Right-click the icon for Refresh Now, Open at Login, About and Quit.
3. Turn on Open at Login to keep ChargeLens in the menu bar from the moment the Mac starts.

Permissions

1. No special permissions are needed; ChargeLens reads the battery information macOS already publishes and the Bluetooth device list from System Information.
2. Allow notifications when macOS asks, if alerts are wanted. Saying no leaves everything else working.
3. Nothing is uploaded, there is no account, and the app never connects to the internet.

If something does not happen

1. A device is missing: only connected devices are listed. Wake it by pressing a key or moving it, then press refresh.
2. AirPods show no levels: put them in your ears or open the case near the Mac, then refresh. macOS only reports them while they are active.
3. No notifications arrive: check System Settings, Notifications, ChargeLens, and make sure alerts are allowed, then check the level under Low Battery Alert.
4. The full charge reminder never fires: Optimised Battery Charging can hold the charge below the chosen level. Pick a lower level, such as 80%.
5. The chart is empty: it fills in as readings are taken. Give it a little while after first launch.

Get ChargeLens

ChargeLens is available on 1dot1 as a single download, with the guide, a README and the licence inside the zip.

Get It Now