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ACPI battery protocol

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Fredrik Orderud edited this page Oct 28, 2025 · 10 revisions

Collection of ACPI packages associated with battery parameters.

Battery Information Extended (_BIX)

This information remains constant until the battery is changed.

Package {
   // ASCIIZ is ASCII character string terminated with a 0x00.
   Revision                            //Integer
   Power Unit                          //Integer (DWORD)
   Design Capacity                     //Integer (DWORD)
   Last Full Charge Capacity           //Integer (DWORD)
   Battery Technology                  //Integer (DWORD)
   Design Voltage                      //Integer (DWORD)
   Design Capacity of Warning          //Integer (DWORD)
   Design Capacity of Low              //Integer (DWORD)
   Cycle Count                         //Integer (DWORD)
   Measurement Accuracy                //Integer (DWORD)
   Max Sampling Time                   //Integer (DWORD)
   Min Sampling Time                   //Integer (DWORD)
   Max Averaging Interval              //Integer (DWORD)
   Min Averaging Interval              //Integer (DWORD)
   Battery Capacity Granularity 1      //Integer (DWORD)
   Battery Capacity Granularity 2      //Integer (DWORD)
   Model Number                        //String (ASCIIZ)
   Serial Number                       //String (ASCIIZ)
   Battery Type                        //String (ASCIIZ)
   OEM Information                     //String (ASCIIZ)
   Battery Swapping Capability         //Integer (DWORD)
}

Source: UEFI ACPI 10. Power Source and Power Meter Devices specification.

Battery Status (_BST)

The present battery status. Whenever the Battery State value changes, the system will generate an SCI to notify the OS.

Package {
   Battery State               // Integer (DWORD)
   Battery Present Rate        // Integer (DWORD)
   Battery Remaining Capacity  // Integer (DWORD)
   Battery Present Voltage     // Integer (DWORD)
}

Source: UEFI ACPI 10. Power Source and Power Meter Devices specification.

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