Understand your battery watts.
Enter Anode’s signed net battery watts, not your charger rating. No device access or charging control.
Example: the battery is supplying power while plugged in
A sustained negative net reading while connected can mean the workload exceeds external power. Recheck several readings and any intentional discharge setting before blaming hardware.
A rating is not a measurement
A 67 W adapter rating describes a power source’s capability. A +24 W battery reading describes net energy entering the battery after the Mac’s own demand. Subtracting those two values does not measure your Mac’s workload or charging efficiency.
Use a pattern, not one sample
Watch several readings with a similar workload. Check the macOS battery message, charging settings and a known-good cable and adapter. This explainer cannot diagnose a fault, calculate reliable remaining runtime or prove battery health. Stop using damaged or swollen hardware and seek qualified service.
Read about plugged-in battery drain · Understand positive, negative and zero watts · Compare monitoring and charging-control tools
Reviewed 6 October 2026. Apple explains workload and charging checks. Interpretation uses Anode’s signed net-watts convention, not a universal sign convention for every battery app.