Battery Health Center Manual GitHub
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Health

By Alexis Rios-Negron · Battery Health Center 0.6.6

Every battery loses a little capacity with age. The Health page measures how much, shows how it has changed over time, and tells you when it is worth doing something about it.

The Health page with the Capacity card on the left and the Capacity Over Time chart on the right.
The Health page: capacity and usage on the left, the long-term trend and battery details on the right.

Capacity#

The Capacity card: Maximum Capacity 86.8 percent, Condition Normal, Full Charge Capacity 44.2 Wh, Design Capacity 51.0 Wh and Capacity Lost 6.8 Wh (13.2 percent).
The Capacity card compares what the battery holds now with what it held when new.
  • Maximum Capacity is the energy the battery holds when full now, as a percentage of what it held when it was new, shown with a level bar.
  • Full Charge Capacity is that energy in watt-hours (Wh). Design Capacity is what the manufacturer rated the battery for when new. Capacity Lost is the difference in Wh and in percent.
  • Condition turns the number into a plain word:
ConditionMaximum capacityWhat it means
Normal80% or moreThe battery is functioning normally.
Worn60% to 80%The battery holds less charge than when new but works normally.
Service RecommendedUnder 60%The battery holds significantly less charge; consider replacing it.

Note. Some drivers report charge in µAh (charge-based) and others in µWh (energy-based). The app supports both.

Capacity over time and the trend#

A chart of capacity from 70 to 100 percent over three weeks with a dashed line at 80 percent, and a Trend row saying 14 of 5 readings and 12 of 14 days.
Capacity is recorded once a day. The dashed line marks 80%, the usual point where a battery is considered worn.

The app records the maximum capacity once a day (the first time it runs that day) and plots it. Readings wobble a little from day to day, so the line is the direction that matters, not any single point.

After at least 5 daily readings spanning at least 14 days the Trend row switches from progress ("3/5 readings · 6/14 days") to a result:

  • N% per month, the rate at which capacity is falling, and Reaches 80%: the month and year the battery is projected to cross 80% ("Around March 2028").
  • Not declining when the line is flat or rising.
  • Already below 80% when it has already crossed.

A battery that does not report capacity data shows "This battery does not report capacity data, so a health trend cannot be calculated."

Tip. Turn on Record History in the Background on the Usage page so the daily reading is saved even on days you never open the window.

Usage#

A Usage card with Cycle Count 214, Current Charge 44.2 Wh, Average Draw on Battery over 24 hours 13.8 W, Voltage 12.85 V and Minimum Design Voltage 11.52 V.
Cycle count and live electrical readings.
  • Cycle Count is how many full charge-and-discharge equivalents the battery has been through. Most laptop batteries are rated for 300–1000 cycles.
  • Current Charge is the energy in the battery now, in Wh.
  • Average Draw on Battery (24 h) is the average power the laptop used while on battery over the last day. It appears once there is enough history.
  • Voltage and Minimum Design Voltage: the present voltage and the lowest voltage the battery is designed to reach.

Rows the battery does not report are shown as "Not reported", and rows with no history yet say "No data yet".

Battery information#

A Battery Information card listing the manufacturer, model, serial number, chemistry and device name.
The details of the battery itself. The serial number is hidden in this screenshot.

Manufacturer, model, serial number, chemistry (for example Li-ion or Li-poly) and the device name Linux uses (BAT0). It is handy for warranty claims and when you shop for a replacement.

Calibration#

A Calibration card with the text Not running, You'll get a notification at each step, and a Start button.
Start a guided calibration from the Calibration card.

Battery gauges estimate the charge. When the percentage jumps around, or the laptop shuts down before it reaches 0%, the estimate has drifted. Calibration lets the battery relearn its true capacity. It takes a full charge, a full discharge and another full charge, usually a few hours in total, and you can use the laptop normally in between.

  1. Choose Start and confirm Start Calibration?. If the laptop is not full, plug it in; the card shows "Step 1 of 3: Charge to 100%".
  2. When the battery is full you get the notification Calibration: Unplug Your Laptop. Unplug the charger and use the laptop until the battery is nearly empty (5%). The card shows "Step 2 of 3" with the current percentage.
  3. At 5% you get Calibration: Plug In Now. Connect the charger and let it charge to 100% again.
  4. You get Calibration Complete. The battery's capacity reading has been recalibrated, and your charge limit is back on.
The Start Calibration confirmation dialog on top of the Health page.
The confirmation explains the three steps before anything starts.

Careful. During calibration the charge limit is lifted so the battery can reach 100%. Choose Cancel on the card at any time to stop; your limit returns.

Hardware. Calibration needs a battery that reports its charge accurately. It is a fix for a wrong reading, not for a battery that has genuinely worn out: if the maximum capacity stays low afterwards, that number is the truth.