SLUUDA0A April   2026  – July 2026 BQ27Z855

 

  1.   1
  2.   Read This First
    1.     About This Manual
    2.     Notational Conventions
    3.     Battery Notational Conventions
    4.     Trademarks
    5.     Glossary
  3. 1 IO Options
    1. 1.1 Configuration of the INT Pin
  4. 2 Basic Measurement System
    1. 2.1 Introduction
    2. 2.2 Current and Coulomb Counting
    3. 2.3 Voltage
      1. 2.3.1 Cell Voltage
      2. 2.3.2 Pack Voltage
    4. 2.4 Temperature
      1. 2.4.1 Internal Temperature
      2. 2.4.2 Cell Temperature
      3. 2.4.3 Temperature Configuration
  5. 3 Protections
    1. 3.1  Introduction
    2. 3.2  Cell Undervoltage Protection
    3. 3.3  Cell Undervoltage Compensated Protection
    4. 3.4  Cell Overvoltage Protection
    5. 3.5  Overcurrent in Charge Protection
    6. 3.6  Overcurrent in Discharge Protection
    7. 3.7  Hardware-Based Protection
      1. 3.7.1 Analog Over Current Charge Protection (AOCC)
      2. 3.7.2 Analog Over Current Discharge Protection (AOCD)
      3. 3.7.3 Short Circuit in Discharge Protection
      4. 3.7.4 ACUV (Cell Under Voltage)
      5. 3.7.5 ACOV (Cell Over Voltage)
    8. 3.8  Temperature Protections
      1. 3.8.1 Overtemperature in Charge Protection
      2. 3.8.2 Overtemperature in Discharge Protection
      3. 3.8.3 Overtemperature FET Protection
      4. 3.8.4 Undertemperature in Charge Protection
      5. 3.8.5 Undertemperature in Discharge Protection
    9. 3.9  Host Watchdog Protection
    10. 3.10 Precharge Timeout Protection
    11. 3.11 Fast Charge Timeout Protection
    12. 3.12 Overcharge Protection
    13. 3.13 OverCharging Voltage Protection
    14. 3.14 OverCharging Current Protection
    15. 3.15 OverPrecharging Current Protection
  6. 4 Integrated Short-Circuit Indication (ISI)
    1. 4.1 Introduction
    2. 4.2 Configuration
      1. 4.2.1 Self-Discharge Current
      2. 4.2.2 Low Internal Short Threshold
      3. 4.2.3 High Internal Short Threshold
      4. 4.2.4 Threshold Passes to Completion
      5. 4.2.5 Manufacturing Completion Timeout
    3. 4.3 ISI Configuration Parameters
      1. 4.3.1 ISI Configuration
      2. 4.3.2 ISI Configuration
  7. 5 Permanent Fail
    1. 5.1  Introduction
      1. 5.1.1 Black Box Recorder
    2. 5.2  Safety Cell Undervoltage Permanent Fail
      1. 5.2.1 SUV Check Option
    3. 5.3  Safety Cell Overvoltage Permanent Fail
    4. 5.4  Safety Overcurrent in Charge Permanent Fail
    5. 5.5  Safety Overcurrent in Discharge Permanent Fail
    6. 5.6  Safety Overtemperature Cell Permanent Fail
    7. 5.7  Safety Overtemperature FET Permanent Fail
    8. 5.8  Capacity Degradation Permanent Fail
    9. 5.9  Charge FET Permanent Fail
    10. 5.10 Discharge FET Permanent Fail
    11. 5.11 Battery Swelling Detection Permanent Fail
    12. 5.12 Data Flash (DF) Permanent Fail
    13. 5.13 Cell Overvoltage Latch Permanent Failure
    14. 5.14 Manual Permanent Failure
    15. 5.15 Permanent Fail ISI
    16. 5.16 Internal Short-Circuit Indication Low Permanent Fail
    17. 5.17 Internal Short-Circuit Indication High Permanent Fail
  8. 6 Power Modes
    1. 6.1  NORMAL Mode
      1. 6.1.1 System Present Detection Configuration
        1. 6.1.1.1 System Present
        2. 6.1.1.2 Battery Pack Removed
    2. 6.2  SLEEP Mode
      1. 6.2.1 Device Sleep
      2. 6.2.2 IN SYSTEM SLEEP Mode
      3. 6.2.3 ManufacturerAccess() MAC Sleep
      4. 6.2.4 Current Wake Function
    3. 6.3  SHIP Mode
    4. 6.4  SHELF Mode
    5. 6.5  SHUTDOWN Mode
      1. 6.5.1 VOLTAGE BASED SHUTDOWN
      2. 6.5.2 ManufacturerAccess() MAC Shutdown
      3. 6.5.3 Time-Based Shutdown
      4. 6.5.4 Low RSOC Time-Based Shutdown
      5. 6.5.5 Power Save Shutdown
      6. 6.5.6 IO Based Shutdown
    6. 6.6  Startup ENAB Hold Time
    7. 6.7  Option to Manage Unintended Wakeup from Shutdown
    8. 6.8  Emergency FET Shutdown (EMSHUT)
      1. 6.8.1 Enter Emergency FET Shutdown Through SHUTDN
      2. 6.8.2 Enter Emergency FET Shutdown Through MFC
      3. 6.8.3 Exit Emergency FET Shutdown
    9. 6.9  STORAGE Mode
    10. 6.10 System Disconnect
  9. 7 Gauging
    1. 7.1  Introduction
    2. 7.2  Dynamic Z-Track Configuration
    3. 7.3  Gas Gauge Modes
    4. 7.4  QMax and Ra
      1. 7.4.1 QMax Initial Values
      2. 7.4.2 QMax Update Conditions
      3. 7.4.3 OCV Prediction
      4. 7.4.4 Fast Qmax Update Conditions
      5. 7.4.5 QMax and Fast Qmax Update Boundary Check
      6. 7.4.6 Ra Table Initial Values
      7. 7.4.7 Ra Table Update Conditions
      8. 7.4.8 Application of Resistance Scaling
    5. 7.5  FullChargeCapacity(FCC), RemainingCapacity(RemCap), and RelativeStateOfCharge(RSOC)
    6. 7.6  Dynamic Z-Track Configuration Options
    7. 7.7  State of Health (SOH)
    8. 7.8  RSOC Rounding Option
    9. 7.9  RSOC 1% Hold
    10. 7.10 Accumulated Charge Measurement
  10. 8 Gauging for Silicon Anode Battery
    1. 8.1 Introduction
    2. 8.2 Capacity Loss And OCV Drift
    3. 8.3 Silicon Anode Battery Gauging
    4. 8.4 Silicon Anode Gauging Parameters
    5. 8.5 Design Qmax
    6. 8.6 ManufacturerAccess() 0x0040 SiAnode Status
    7. 8.7 ZT SiAnode Gauging Configuration
  11. 9 Lifetime Data Collection
    1. 9.1 Description
    2. 9.2 Reset
  12. 10Linear Charging Functions
    1. 10.1 Introduction
    2. 10.2 Charger Detect (CHGR_DET) Functionality
    3. 10.3 CHG FET FSM and Mode-to-mode Switching (Linear Charger Modes)
    4. 10.4 Linear Charge Profile
  13. 11Charge Current Derating
  14. 12Charge Current Derating Data Flash Parameters
  15. 13Host Interrupts
    1. 13.1 Description
    2. 13.2 Host Interrupts Configuration
  16. 14Device Security
    1. 14.1 Description
    2. 14.2 SHA-256 Authentication
      1. 14.2.1 Authentication Flow
    3. 14.3 Security Modes
      1. 14.3.1 SEALING and UNSEALING Data Flash
      2. 14.3.2 SEALED to UNSEALED
      3. 14.3.3 UNSEALED to FULL ACCESS
  17. 15ECC
    1. 15.1 Introduction
    2. 15.2 Gauge Authentication
    3. 15.3 ECC MAC Commands Description
  18. 16Advanced Charge Algorithm
    1. 16.1  Introduction
    2. 16.2  Charge Temperature Ranges
    3. 16.3  Voltage Range
      1. 16.3.1 Voltage or RelativeStateofCharge() Range
    4. 16.4  Charging Current
    5. 16.5  Charging Voltage
    6. 16.6  Valid Charge Termination
    7. 16.7  Charge and Discharge Termination Flags
    8. 16.8  Terminate Charge and Discharge Alarms
    9. 16.9  Zero Volt Charging (ZVCHG)
    10. 16.10 Precharge
    11. 16.11 Maintenance Charge
    12. 16.12 Charge Disabled
    13. 16.13 Charge Inhibit
    14. 16.14 Charge Suspend
    15. 16.15 ChargingVoltage() Rate of Change
    16. 16.16 ChargingCurrent() Rate of Change
    17. 16.17 Charging Loss Compensation
    18. 16.18 Cycle Count/SOH Based Degradation of Charging Voltage and Current
      1. 16.18.1 Degradation Modes
        1. 16.18.1.1 Cycle Count Based Degradation
        2. 16.18.1.2 SOH Based Degradation
        3. 16.18.1.3 Runtime Based Degradation
      2. 16.18.2 Degradation Process
        1. 16.18.2.1 Charging Voltage Degradation Process
        2. 16.18.2.2 Charging Current Degradation Process
    19. 16.19 Elevated Charge Degradation
    20. 16.20 Elevated Voltage Extended Charge Degradation
    21. 16.21 Charge Voltage Compensation for System Impedance
    22. 16.22 Cell Swelling Control (via Charging Voltage Degradation)
  19. 17Communications
    1. 17.1 I2C Interface
      1. 17.1.1 I2C Clock Frequency
      2. 17.1.2 I2C Time Out
      3. 17.1.3 I2C Command Waiting Time
      4. 17.1.4 I2C Clock Stretching
  20. 18Calibration
    1. 18.1 Voltage Calibration
      1. 18.1.1 Cell (BAT) Voltage Calibration
      2. 18.1.2 Pack (PACK) Voltage Calibration
      3. 18.1.3 Voltage Calibration Data Flash
    2. 18.2 Current Calibration
      1. 18.2.1 CC Gain/Capacity Gain Calibration
      2. 18.2.2 Deadbands
        1. 18.2.2.1 Current Deadband
        2. 18.2.2.2 Coulomb Counter Deadband
      3. 18.2.3 Current Calibration Data Flash
    3. 18.3 Temperature Calibration
      1. 18.3.1 TS Calibration
      2. 18.3.2 Temperature Calibration Data Flash
      3. 18.3.3 Cell Temp Model
      4. 18.3.4 Internal Temp Model
  21. 19Data Commands
    1. 19.1 Standard Data Commands
      1. 19.1.1  0x00/01 ManufacturerAccess()/ControlStatus()
      2. 19.1.2  0x02/03 AtRate()
      3. 19.1.3  0x04/05 AtRateTimeToEmpty()
      4. 19.1.4  0x06/07 Temperature()
      5. 19.1.5  0x08/09 Voltage()
      6. 19.1.6  0x0A/0B BatteryStatus()
      7. 19.1.7  0x0C/0D Current()
      8. 19.1.8  0x10/11 RemainingCapacity()
      9. 19.1.9  0x12/13 FullChargeCapacity()
      10. 19.1.10 0x14/15 AverageCurrent()
      11. 19.1.11 0x16/17 AverageTimeToEmpty()
      12. 19.1.12 0x18/19 AverageTimeToFull()
      13. 19.1.13 0x20/21 MaxLoadTimeToEmpty()
      14. 19.1.14 0x22/23 AveragePower()
      15. 19.1.15 0x28/29 InternalTemperature()
      16. 19.1.16 0x2A/2B CycleCount()
      17. 19.1.17 0x2C/2D RelativeStateOfCharge()—RSOC
      18. 19.1.18 0x2E/2F StateOfHealth()
      19. 19.1.19 0x30/31 ChargingVoltage()
      20. 19.1.20 0x32/33 ChargingCurrent()
      21. 19.1.21 0x34/35 TerminateVoltage()
      22. 19.1.22 0x36/0x37/0x38/0x39 Timestamp()
      23. 19.1.23 QMax Cycles() 0x3A/3B
      24. 19.1.24 0x3C/3D DesignCapacity()
      25. 19.1.25 0x3E/3F AltManufacturerAccess()
      26. 19.1.26 0x40/0x5F MACData()
      27. 19.1.27 0x60 MACDataChecksum()
      28. 19.1.28 0x61 MACDataLength()
    2. 19.2 0x00, 0x01 ManufacturerAccess() and 0x3E, 0x3F AltManufacturerAccess()
      1. 19.2.1  ManufacturerAccess() 0x0000
      2. 19.2.2  ManufacturerAccess() 0x0001 Device Type
      3. 19.2.3  ManufacturerAccess() 0x0002 Firmware Version
      4. 19.2.4  ManufacturerAccess() 0x0003 Hardware Version
      5. 19.2.5  ManufacturerAccess() 0x0004 Instruction Flash Signature
      6. 19.2.6  ManufacturerAccess() 0x0005 Static DF Signature
      7. 19.2.7  ManufacturerAccess() 0x0006 Chemical ID
      8. 19.2.8  ManufacturerAccess() 0x0008 Static Chem DF Signature
      9. 19.2.9  ManufacturerAccess() 0x0009 All DF Signature
      10. 19.2.10 ManufacturerAccess() 0x000A STORAGE Mode
      11. 19.2.11 ManufacturerAccess() 0x0010 SHUTDOWN Mode
      12. 19.2.12 ManufacturerAccess() 0x0011 SLEEP Mode
      13. 19.2.13 ManufacturerAccess() 0x001F CHG FET Toggle
      14. 19.2.14 ManufacturerAccess() 0x0020 DSG FET Toggle
      15. 19.2.15 ManufacturerAccess() 0x0021 Gauging
      16. 19.2.16 ManufacturerAccess() 0x0022 FET Control
      17. 19.2.17 ManufacturerAccess() 0x0023 Lifetime Data Collection
      18. 19.2.18 ManufacturerAccess() 0x0024 Permanent Failure
      19. 19.2.19 ManufacturerAccess() 0x0025 Black Box Recorder
      20. 19.2.20 ManufacturerAccess() 0x0028 Lifetime Data Reset
      21. 19.2.21 ManufacturerAccess() 0x0029 Permanent Fail Data Reset
      22. 19.2.22 ManufacturerAccess() 0x002A Black Box Recorder Reset
      23. 19.2.23 ManufacturerAccess() 0x002D CALIBRATION Mode
      24. 19.2.24 ManufacturerAccess() 0x002E Lifetime Data Flush
      25. 19.2.25 ManufacturerAccess() 0x002F Lifetime Data SPEED UP Mode
      26. 19.2.26 ManufacturerAccess() 0x0030 Seal Device
      27. 19.2.27 ManufacturerAccess() 0x0035 Security Keys
      28. 19.2.28 ManufacturerAccess() 0x0037 Authentication Key
      29. 19.2.29 ManufacturerAccess() 0x0041 Device Reset
      30. 19.2.30 ManufacturerAccess() 0x0050 SafetyAlert
      31. 19.2.31 ManufacturerAccess() 0x0051 SafetyStatus
      32. 19.2.32 ManufacturerAccess() 0x0052 PFAlert
      33. 19.2.33 ManufacturerAccess() 0x0053 PFStatus
      34. 19.2.34 ManufacturerAccess() 0x0054 OperationStatus
      35. 19.2.35 ManufacturerAccess() 0x0055 ChargingStatus
      36. 19.2.36 ManufacturerAccess() 0x0056 GaugingStatus
      37. 19.2.37 ManufacturerAccess() 0x0057 ManufacturingStatus
      38. 19.2.38 ManufacturerAccess() 0x0058 AFE Register
      39. 19.2.39 ManufacturerAccess() 0x005C VCT Voltage
      40. 19.2.40 ManufacturerAccess() 0x005E ChargingStatusExt
      41. 19.2.41 ManufacturerAccess() 0x0060 Lifetime Data Block 1
      42. 19.2.42 ManufacturerAccess() 0x0061 Lifetime Data Block 2
      43. 19.2.43 ManufacturerAccess() 0x0062 Lifetime Data Block 3
      44. 19.2.44 ManufacturerAccess() 0x0063 Lifetime Data Block 4
      45. 19.2.45 ManufacturerAccess() 0x0064 Lifetime Data Block 5
      46. 19.2.46 ManufacturerAccess() 0x0065 Lifetime Data Block 6
      47. 19.2.47 ManufacturerAccess() 0x0066 Lifetime Data Block 7
      48. 19.2.48 ManufacturerAccess() 0x0067 Lifetime Data Block 8
      49. 19.2.49 ManufacturerAccess() 0x0068 Lifetime Data Block 9
      50. 19.2.50 ManufacturerAccess() 0x0069 Lifetime Data Block 10
      51. 19.2.51 ManufacturerAccess() 0x006A Lifetime Data Block 11
      52. 19.2.52 ManufacturerAccess() 0x006B Lifetime Data Block 12
      53. 19.2.53 ManufacturerAccess() 0x006C Lifetime Data Block 13
      54. 19.2.54 ManufacturerAccess() 0x006D Lifetime Data Block 14
      55. 19.2.55 ManufacturerAccess() 0x006E Lifetime Data Block 15
      56. 19.2.56 ManufacturerAccess() 0x006F Power Events
      57. 19.2.57 ManufacturerAccess() 0x0070 ManufacturerInfo
      58. 19.2.58 ManufacturerAccess() 0x0071 DAStatus1
      59. 19.2.59 ManufacturerAccess() 0x0072 DAStatus2
      60. 19.2.60 ManufacturerAccess() 0x0073 GaugeStatus1
      61. 19.2.61 ManufacturerAccess() 0x0074 GaugeStatus2
      62. 19.2.62 ManufacturerAccess() 0x0075 GaugeStatus3
      63. 19.2.63 ManufacturerAccess() 0x0076 CBStatus
      64. 19.2.64 ManufacturerAccess() 0x0077 StateofHealth
      65. 19.2.65 ManufacturerAccess() 0x0078 FilterCapacity
      66. 19.2.66 ManufacturerAccess() 0x0079 RSOCWrite
      67. 19.2.67 ManufacturerAccess() 0x007A ManufacturerInfoB
      68. 19.2.68 ManufacturerAccess() 0x007B ManufacturerInfoC
      69. 19.2.69 ManufacturerAccess() 0x007E Lifetime Data Block 16
      70. 19.2.70 ManufacturerAccess() 0x0098 AccumulationChargeEnable
      71. 19.2.71 ManufacturerAccess() 0x0099 AccumulationDischargeEnable
      72. 19.2.72 ManufacturerAccess() 0x009A AccumulationReset
      73. 19.2.73 ManufacturerAccess() 0x009B AccumulationStop
      74. 19.2.74 ManufacturerAccess() 0x009C AccumulationStart
      75. 19.2.75 ManufacturerAccess() 0x009D AccumulationChargeThreshold
      76. 19.2.76 ManufacturerAccess() 0x009E AccumulationDischargeThreshold
      77. 19.2.77 ManufacturerAccess() 0x009F AccumulatedChargeTime
      78. 19.2.78 ManufacturerAccess() 0x00B0 ChargingVoltageOverride
      79. 19.2.79 ManufacturerAccess() 0x00B2 ChargingCurrentOverride
      80. 19.2.80 ManufacturerAccess() 0x00B4 RTC Access
      81. 19.2.81 ManufacturerAccess() 0x00B5 ChargerStatus
      82. 19.2.82 ManufacturerAccess() 0x00D2 ISI Current State
      83. 19.2.83 ManufacturerAccess() 0x00F0 IATAShutdown
      84. 19.2.84 ManufacturerAccess() 0x00F1 IATARm
      85. 19.2.85 ManufacturerAccess() 0x00F2 IATAFcc
      86. 19.2.86 ManufacturerAccess() 0x0F00 ROM Mode
      87. 19.2.87 ManufacturerAccess() 0x3008 WriteTemp
      88. 19.2.88 ManufacturerAccess() 0x4000–0x5FFF DataFlashAccess
      89. 19.2.89 ManufacturerAccess() 0xF080 and 0xF081 Output CCADCCal Control
      90. 19.2.90 ManufacturerAccess() 0xF082 OutputShortedCCADCCal
  22. 20Data Flash Values
    1. 20.1  Settings
      1. 20.1.1  Configuration
        1. 20.1.1.1  Charging Configuration
        2. 20.1.1.2  Charging Configuration Ext
        3. 20.1.1.3  FET Options
        4. 20.1.1.4  SBS Gauging Configuration
        5. 20.1.1.5  SBS Configuration
        6. 20.1.1.6  Auth Config
        7. 20.1.1.7  Power Config
        8. 20.1.1.8  IO Config
        9. 20.1.1.9  Temperature Enable
        10. 20.1.1.10 Temperature Mode
        11. 20.1.1.11 DA Configuration
        12. 20.1.1.12 SOC Flag Config A
        13. 20.1.1.13 SOC Flag Config B
        14. 20.1.1.14 IT Gauging Configuration
        15. 20.1.1.15 IT Gauging Ext
        16. 20.1.1.16 Elevated Degrade Configuration
        17. 20.1.1.17 DZT Gauging Configuration
      2. 20.1.2  Flag Map
        1. 20.1.2.1 Set Up 1 Configuration
        2. 20.1.2.2 Set Up 1 Pin Number
        3. 20.1.2.3 Set Up 2 Configuration
        4. 20.1.2.4 Set Up 2 Pin Number
        5. 20.1.2.5 Set Up 3 Configuration
        6. 20.1.2.6 Set Up 3 Pin Number
        7. 20.1.2.7 Set Up 4 Configuration
        8. 20.1.2.8 Set Up 4 Pin Number
      3. 20.1.3  GPIO
        1. 20.1.3.1  Pres Pin Number
        2. 20.1.3.2  Disconnect Pin Number
        3. 20.1.3.3  Emergency Shutdown Pin Number
        4. 20.1.3.4  IO Shutdown Pin Number
        5. 20.1.3.5  BTP Pin Number
        6. 20.1.3.6  BTP Pin Configuration
        7. 20.1.3.7  GPIO_PF Pin Number
        8. 20.1.3.8  GPIO_INT Enable
        9. 20.1.3.9  GPIO_INT Output Enable
        10. 20.1.3.10 GPIO_INT Default Out
        11. 20.1.3.11 Sealed Access Config
      4. 20.1.4  BTP
        1. 20.1.4.1 Init Discharge Set
        2. 20.1.4.2 Init Charge Set
        3. 20.1.4.3 Init Charge SOC Set
        4. 20.1.4.4 Init Discharge SOC Set
      5. 20.1.5  Sealed Access
        1. 20.1.5.1 DF Only Read Timeout
        2. 20.1.5.2 MfgInfoC Write Timeout
      6. 20.1.6  Lifetimes
        1. 20.1.6.1 Lifetimes Configuration
        2. 20.1.6.2 Time RSOC Thresholds
        3. 20.1.6.3 Temperature Hold-off Time
        4. 20.1.6.4 Time Temperature Limits
      7. 20.1.7  Protection
        1. 20.1.7.1 Protection Configuration
        2. 20.1.7.2 Enabled Protections A
        3. 20.1.7.3 Enabled Protections B
        4. 20.1.7.4 Enabled Protections C
        5. 20.1.7.5 Enabled Protections D
      8. 20.1.8  Permanent Failure
        1. 20.1.8.1 Enabled PF A
        2. 20.1.8.2 Enabled PF B
        3. 20.1.8.3 Enabled PF C
        4. 20.1.8.4 Enabled PF D
      9. 20.1.9  AFE
        1. 20.1.9.1  OCC
        2. 20.1.9.2  OCD
        3. 20.1.9.3  Short Circuit Discharge
        4. 20.1.9.4  Under Voltage
        5. 20.1.9.5  Over Voltage
        6. 20.1.9.6  Current Charge Wake
        7. 20.1.9.7  Current Discharge Wake
        8. 20.1.9.8  OCC Delay
        9. 20.1.9.9  OCD Delay
        10. 20.1.9.10 Short Circuit Discharge Delay
        11. 20.1.9.11 Under Voltage Delay
        12. 20.1.9.12 Over Voltage Delay
        13. 20.1.9.13 Over Voltage Delay Hi
        14. 20.1.9.14 CD Wake Delay
        15. 20.1.9.15 CC Wake Delay
        16. 20.1.9.16 ZVCHG Exit Threshold
      10. 20.1.10 Smart Temperature
        1. 20.1.10.1 Mid Point Temp
      11. 20.1.11 Manufacturing
        1. 20.1.11.1 Manufacturing Status Init
      12. 20.1.12 Accumulated Charge Measurement
        1. 20.1.12.1 Accum Discharge Threshold
        2. 20.1.12.2 Accum Charge Threshold
    2. 20.2  Advanced Charging Algorithm
      1. 20.2.1  Minimum System Voltage
      2. 20.2.2  CHGR_DET Off Voltage
      3. 20.2.3  CHGR_DET On Voltage
      4. 20.2.4  Temperature Ranges
        1. 20.2.4.1  T1 Temp
        2. 20.2.4.2  Hysteresis Temp T1
        3. 20.2.4.3  T2 Temp
        4. 20.2.4.4  Hysteresis Temp T2
        5. 20.2.4.5  T5 Temp
        6. 20.2.4.6  Hysteresis Temp T5
        7. 20.2.4.7  T6 Temp
        8. 20.2.4.8  Hysteresis Temp T6
        9. 20.2.4.9  T3 Temp
        10. 20.2.4.10 Hysteresis Temp T3
        11. 20.2.4.11 T4 Temp
        12. 20.2.4.12 Hysteresis Temp T4
      5. 20.2.5  PreCharging
      6. 20.2.6  Maintenance Charging
      7. 20.2.7  Voltage Range
        1. 20.2.7.1 Precharge Start Voltage
        2. 20.2.7.2 Charging Voltage Low
        3. 20.2.7.3 Charging Voltage Med
        4. 20.2.7.4 Charging Voltage High
        5. 20.2.7.5 Charging Voltage Hysteresis
      8. 20.2.8  Degrade Mode 1
        1. 20.2.8.1 Cycle Threshold
        2. 20.2.8.2 SOH Threshold
        3. 20.2.8.3 Runtime Threshold
        4. 20.2.8.4 Voltage Degradation
        5. 20.2.8.5 Current Degradation
      9. 20.2.9  Degrade Mode 2
        1. 20.2.9.1 Cycle Threshold
        2. 20.2.9.2 SOH Threshold
        3. 20.2.9.3 Runtime Threshold
        4. 20.2.9.4 Voltage Degradation
        5. 20.2.9.5 Current Degradation
      10. 20.2.10 Degrade Mode 3
        1. 20.2.10.1 Cycle Threshold
        2. 20.2.10.2 SOH Threshold
        3. 20.2.10.3 Runtime Threshold
        4. 20.2.10.4 Voltage Degradation
        5. 20.2.10.5 Current Degradation
      11. 20.2.11 Degrade Mode
        1. 20.2.11.1 Runtime Degrade
        2. 20.2.11.2 Runtime Update Interval
        3. 20.2.11.3 Cycle Count Start Runtime
      12. 20.2.12 CS Degrade
        1. 20.2.12.1 Temperature Threshold
        2. 20.2.12.2 Voltage Threshold
        3. 20.2.12.3 Time Interval
        4. 20.2.12.4 Delta Voltage
        5. 20.2.12.5 Min CV
      13. 20.2.13 Charge Voltage Override
        1. 20.2.13.1 CHGV Override Max
        2. 20.2.13.2 CHGV Override Min
      14. 20.2.14 Charge Current Override
        1. 20.2.14.1 CHGI Override Max
        2. 20.2.14.2 CHGI Override Min
      15. 20.2.15 Termination Config
        1. 20.2.15.1 Minimum Taper Charge
        2. 20.2.15.2 Charge Term Taper Current
        3. 20.2.15.3 Charge Term Voltage Offset
        4. 20.2.15.4 Charge Term Charging Voltage
      16. 20.2.16 Charging Rate of Change
        1. 20.2.16.1 Current Rate
        2. 20.2.16.2 Voltage Rate
      17. 20.2.17 Charge Loss Compensation
        1. 20.2.17.1 CCC Current Threshold
        2. 20.2.17.2 CCC Voltage Threshold
      18. 20.2.18 IR Correction
        1. 20.2.18.1 Averaging Interval
      19. 20.2.19 Sealed Write
        1. 20.2.19.1 Hold Off
        2. 20.2.19.2 Lockout
      20. 20.2.20 Low Temp Charging
        1. 20.2.20.1 Voltage
        2. 20.2.20.2 Current Low
        3. 20.2.20.3 Current Med
        4. 20.2.20.4 Current High
      21. 20.2.21 Standard Temp Low Charging
        1. 20.2.21.1 Voltage
        2. 20.2.21.2 Current Low
        3. 20.2.21.3 Current Med
        4. 20.2.21.4 Current High
      22. 20.2.22 Standard Temp High Charging
        1. 20.2.22.1 Voltage
        2. 20.2.22.2 Current Low
        3. 20.2.22.3 Current Med
        4. 20.2.22.4 Current High
      23. 20.2.23 High Temp Charging
        1. 20.2.23.1 Voltage
        2. 20.2.23.2 Current Low
        3. 20.2.23.3 Current Med
        4. 20.2.23.4 Current High
      24. 20.2.24 Rec Temp Charging
        1. 20.2.24.1 Voltage
        2. 20.2.24.2 Current Low
        3. 20.2.24.3 Current Med
        4. 20.2.24.4 Current High
      25. 20.2.25 Elevated Degrade
        1. 20.2.25.1  Accumulated ERM Time
        2. 20.2.25.2  Accumulated ERETM Time
        3. 20.2.25.3  Accumulated EVLTM Time
        4. 20.2.25.4  Accumulated EVMTM Time
        5. 20.2.25.5  Accumulated EVHTM Time
        6. 20.2.25.6  ERETM Status
        7. 20.2.25.7  EVTM Degrade
        8. 20.2.25.8  EVTM Active
        9. 20.2.25.9  ERM Reset RSoC Threshold
        10. 20.2.25.10 ERM Reset Voltage Threshold
        11. 20.2.25.11 ERM RSoC Threshold
        12. 20.2.25.12 ERM Voltage Threshold
        13. 20.2.25.13 ERM Time Threshold
        14. 20.2.25.14 ERETM RSoC Threshold
        15. 20.2.25.15 ERETM Voltage Threshold
        16. 20.2.25.16 ERETM Temperature Threshold
        17. 20.2.25.17 ERETM Time Threshold
        18. 20.2.25.18 ERETM Charging Voltage
        19. 20.2.25.19 EVTM Voltage Thresholds
        20. 20.2.25.20 EVTM Temperature Thresholds
        21. 20.2.25.21 EVLTM Time Thresholds
        22. 20.2.25.22 EVLTM Delta Charging Voltages
        23. 20.2.25.23 EVMTM Time Thresholds
        24. 20.2.25.24 EVMTM Delta Charging Voltages
        25. 20.2.25.25 EVHTM Time Thresholds
        26. 20.2.25.26 EVHTM Delta Charging Voltages
    3. 20.3  Power
      1. 20.3.1  Power
      2. 20.3.2  Shutdown
        1. 20.3.2.1 Shutdown Voltage
        2. 20.3.2.2 Shutdown Time
        3. 20.3.2.3 IO Shutdown Delay
        4. 20.3.2.4 IO Shutdown Timeout
        5. 20.3.2.5 Low RSoC Shutdown Threshold
        6. 20.3.2.6 Low RSoC Shutdown Time
        7. 20.3.2.7 Charger Present Threshold
      3. 20.3.3  Sleep
        1. 20.3.3.1 Sleep Current
        2. 20.3.3.2 Low Current
        3. 20.3.3.3 Low Current Period
        4. 20.3.3.4 Measure Time
        5. 20.3.3.5 Bus Timeout
        6. 20.3.3.6 Current Time
      4. 20.3.4  Ship
        1. 20.3.4.1 FET Off Time
        2. 20.3.4.2 Delay
        3. 20.3.4.3 Auto Ship Time
      5. 20.3.5  Power Off
      6. 20.3.6  Manual FET Control
      7. 20.3.7  System Present
        1. 20.3.7.1 SysPres Delay
      8. 20.3.8  Storage
        1. 20.3.8.1 Storage Delay
        2. 20.3.8.2 Storage Ignore SMB Delay
      9. 20.3.9  Power Events
        1. 20.3.9.1 Power Events
      10. 20.3.10 IATA
        1. 20.3.10.1 IATA Config
        2. 20.3.10.2 IATA Delay Time
        3. 20.3.10.3 IATA RSOC Threshold
        4. 20.3.10.4 IATA Wake AbsRSOC
        5. 20.3.10.5 IATA MIN Temperature
        6. 20.3.10.6 IATA MAX Temperature
        7. 20.3.10.7 IATA MIN Voltage
        8. 20.3.10.8 IATA MAX Voltage
      11. 20.3.11 IATA STORE
        1. 20.3.11.1 IATA RM mAH
        2. 20.3.11.2 IATA RM cWH
        3. 20.3.11.3 IATA FCC mAH
        4. 20.3.11.4 IATA FCC cWH
        5. 20.3.11.5 IATA Flag
      12. 20.3.12 Unintended Wakeup
        1. 20.3.12.1 Delay
        2. 20.3.12.2 Count
    4. 20.4  System Data
      1. 20.4.1 Manufacturer Info
      2. 20.4.2 Manufacturer Info B
      3. 20.4.3 Manufacturer Info C
      4. 20.4.4 Integrity
        1. 20.4.4.1 Static DF Signature
        2. 20.4.4.2 Static Chem DF
        3. 20.4.4.3 All DF Signature
    5. 20.5  SBS Configuration
      1. 20.5.1 Data
        1. 20.5.1.1  Manufacturer Date
        2. 20.5.1.2  Serial Number
        3. 20.5.1.3  Manufacturer Name
        4. 20.5.1.4  Device Name
        5. 20.5.1.5  Device Chemistry
        6. 20.5.1.6  Remaining Capacity Alarm
          1. 20.5.1.6.1 Remaining Ah Capacity Alarm
          2. 20.5.1.6.2 Remaining Wh Capacity Alarm
        7. 20.5.1.7  RemainingTimeAlarm
        8. 20.5.1.8  Initial Battery Mode
        9. 20.5.1.9  Specification Information
        10. 20.5.1.10 VLB Remaining Capacity
          1. 20.5.1.10.1 VLB Remaining Cap mAh
          2. 20.5.1.10.2 VLB Remaining Cap in cWh
        11. 20.5.1.11 VLB Voltage
        12. 20.5.1.12 VLB Hold Time
        13. 20.5.1.13 VLB Timeout
    6. 20.6  Lifetimes
      1. 20.6.1  Cell 1 Max Voltage
      2. 20.6.2  Cell 1 Min Voltage
      3. 20.6.3  Current
        1. 20.6.3.1 Max Charge Current
        2. 20.6.3.2 Max Discharge Current
        3. 20.6.3.3 Max Avg Dsg Current
        4. 20.6.3.4 Max Avg Dsg Power
      4. 20.6.4  Temperature-Relax
        1. 20.6.4.1 Max Temp Cell
        2. 20.6.4.2 Min Temp Cell
        3. 20.6.4.3 Min Temp Int Sensor
        4. 20.6.4.4 Max Temp Int Sensor
        5. 20.6.4.5 Max Temp Fet
        6. 20.6.4.6 Max Temp TS1
        7. 20.6.4.7 Min Temp TS1
      5. 20.6.5  Max Temp Cell
      6. 20.6.6  Min Temp Cell
      7. 20.6.7  Max Temp Int Sensor
      8. 20.6.8  Min Temp Int Sensor
      9. 20.6.9  Max Temp Fet
      10. 20.6.10 Max Temp TS1
      11. 20.6.11 Min Temp TS1
      12. 20.6.12 Max Temp Cell
      13. 20.6.13 Min Temp Cell
      14. 20.6.14 Max Temp Int Sensor
      15. 20.6.15 Min Temp Int Sensor
      16. 20.6.16 Max Temp Fet
      17. 20.6.17 Max Temp TS1
      18. 20.6.18 Min Temp TS1
      19. 20.6.19 Safety Events
        1. 20.6.19.1  No Of COV Events
        2. 20.6.19.2  Last COV Event
        3. 20.6.19.3  No Of CUV Events
        4. 20.6.19.4  Last CUV Event
        5. 20.6.19.5  No Of OCD1 Events
        6. 20.6.19.6  Last OCD1 Event
        7. 20.6.19.7  No Of OCD2 Events
        8. 20.6.19.8  Last OCD2 Event
        9. 20.6.19.9  No Of OCC1 Events
        10. 20.6.19.10 Last OCC1 Event
        11. 20.6.19.11 No Of OCC2 Events
        12. 20.6.19.12 Last OCC2 Event
        13. 20.6.19.13 No Of AOCD Events
        14. 20.6.19.14 Last AOCD Event
        15. 20.6.19.15 No Of ASCD Events
        16. 20.6.19.16 Last ASCD Event
        17. 20.6.19.17 No Of AOCC Events
        18. 20.6.19.18 Last AOCC Event
        19. 20.6.19.19 No Of OTC Events
        20. 20.6.19.20 Last OTC Event
        21. 20.6.19.21 No Of OTD Events
        22. 20.6.19.22 Last OTD Event
        23. 20.6.19.23 No Of OTF Events
        24. 20.6.19.24 Last OTF Event
      20. 20.6.20 Charging Events
        1. 20.6.20.1 No Valid Charge Term
        2. 20.6.20.2 Last Valid Charge Term
      21. 20.6.21 Gauging Events
        1. 20.6.21.1 No Of Qmax Updates
        2. 20.6.21.2 Last Qmax Update
        3. 20.6.21.3 No Of Ra Updates
        4. 20.6.21.4 Last Ra Update
        5. 20.6.21.5 No Of Ra Disable
        6. 20.6.21.6 Last Ra Disable
      22. 20.6.22 Time
        1. 20.6.22.1 Total Firmware Runtime
        2. 20.6.22.2 Time Spent in LFT_UUT
        3. 20.6.22.3 Time Spent in LFT_UT
        4. 20.6.22.4 Time Spent in LFT_LT
        5. 20.6.22.5 Time Spent in LFT_STL
        6. 20.6.22.6 Time Spent in LFT_RT
        7. 20.6.22.7 Time Spent in LFT_STH
        8. 20.6.22.8 Time Spent in LFT_HT
        9. 20.6.22.9 Time Spent in LFT_OT
    7. 20.7  Protections
      1. 20.7.1  CUV—Cell Undervoltage
        1. 20.7.1.1 Threshold
        2. 20.7.1.2 Delay
        3. 20.7.1.3 Recovery
        4. 20.7.1.4 Recovery Charger Present Time
      2. 20.7.2  CUVC—Cell Undervoltage
        1. 20.7.2.1 Threshold
        2. 20.7.2.2 Delay
        3. 20.7.2.3 Recovery
      3. 20.7.3  ACUV—Cell Under Voltage hardware based
        1. 20.7.3.1 Recovery (ACUV)
      4. 20.7.4  ACOV—Cell Over Voltage hardware based
        1. 20.7.4.1 Recovery (ACOV)
      5. 20.7.5  COV—Cell Overvoltage
        1. 20.7.5.1  Threshold Low Temp
        2. 20.7.5.2  Threshold Standard Temp Low
        3. 20.7.5.3  Threshold Standard Temp High
        4. 20.7.5.4  Threshold High Temp
        5. 20.7.5.5  Threshold Rec Temp
        6. 20.7.5.6  Delay
        7. 20.7.5.7  Recovery Low Temp
        8. 20.7.5.8  Recovery Standard Temp Low
        9. 20.7.5.9  Recovery Standard Temp High
        10. 20.7.5.10 Recovery High Temp
        11. 20.7.5.11 Recovery Rec Temp
        12. 20.7.5.12 Cell Overvoltage Latch Limit
        13. 20.7.5.13 Cell Overvoltage Counter Decrement Delay
        14. 20.7.5.14 Reset
      6. 20.7.6  OCC1—Overcurrent In Charge 1
        1. 20.7.6.1 Threshold
        2. 20.7.6.2 Delay
      7. 20.7.7  OCC2—Overcurrent In Charge 2
        1. 20.7.7.1 Threshold
        2. 20.7.7.2 Delay
      8. 20.7.8  OCC—Overcurrent In Charge Recovery
        1. 20.7.8.1 Recovery Threshold
        2. 20.7.8.2 Recovery Delay
      9. 20.7.9  OCD1—Overcurrent In Discharge 1
        1. 20.7.9.1 Threshold
        2. 20.7.9.2 Delay
      10. 20.7.10 OCD2—Overcurrent In Discharge 2
        1. 20.7.10.1 Threshold
        2. 20.7.10.2 Delay
      11. 20.7.11 OCD—Overcurrent In Discharge Recovery
        1. 20.7.11.1 Recovery Threshold
        2. 20.7.11.2 Recovery Delay
        3. 20.7.11.3 Latch Limit
        4. 20.7.11.4 Counter Dec Delay
        5. 20.7.11.5 Reset
      12. 20.7.12 AOCD—Overload in Discharge
        1. 20.7.12.1 Latch Limit
        2. 20.7.12.2 Counter Dec Delay
        3. 20.7.12.3 Recovery
        4. 20.7.12.4 Reset
      13. 20.7.13 AOCC—Overcurrent In Charge
        1. 20.7.13.1 Latch Limit
        2. 20.7.13.2 Counter Dec Delay
        3. 20.7.13.3 Recovery
        4. 20.7.13.4 Reset
      14. 20.7.14 ASCD—Short Circuit in Discharge
        1. 20.7.14.1 Latch Limit
        2. 20.7.14.2 Counter Dec Delay
        3. 20.7.14.3 Recovery
        4. 20.7.14.4 Reset
      15. 20.7.15 OTC—Overtemperature in Charge
        1. 20.7.15.1 Threshold
        2. 20.7.15.2 Delay
        3. 20.7.15.3 Recovery
      16. 20.7.16 OTD—Overtemperature in Discharge
        1. 20.7.16.1 Threshold
        2. 20.7.16.2 Delay
        3. 20.7.16.3 Recovery
      17. 20.7.17 OTF—Overtemperature FET
        1. 20.7.17.1 Threshold
        2. 20.7.17.2 Delay
        3. 20.7.17.3 Recovery
      18. 20.7.18 UTC—Undertemperature in Charge
        1. 20.7.18.1 Threshold
        2. 20.7.18.2 Delay
        3. 20.7.18.3 Recovery
      19. 20.7.19 UTD—Undertemperature in Discharge
        1. 20.7.19.1 Threshold
        2. 20.7.19.2 Delay
        3. 20.7.19.3 Recovery
      20. 20.7.20 HWD—Host Watchdog
      21. 20.7.21 PTO—PRECHARGE Mode Time Out
        1. 20.7.21.1 Charge Threshold
        2. 20.7.21.2 Suspend Threshold
        3. 20.7.21.3 Delay
        4. 20.7.21.4 Reset
      22. 20.7.22 CTO—Fast Charge Mode Time Out
        1. 20.7.22.1 Charge Threshold
        2. 20.7.22.2 Suspend Threshold
        3. 20.7.22.3 Delay
        4. 20.7.22.4 Reset
      23. 20.7.23 OC—Overcharge
        1. 20.7.23.1 Threshold
        2. 20.7.23.2 Recovery
        3. 20.7.23.3 RSOC Recovery
      24. 20.7.24 CHGV—ChargingVoltage
        1. 20.7.24.1 Threshold
        2. 20.7.24.2 Delay
        3. 20.7.24.3 Recovery
      25. 20.7.25 CHGC—ChargingCurrent
        1. 20.7.25.1 Threshold
        2. 20.7.25.2 Delay
        3. 20.7.25.3 Recovery Threshold
        4. 20.7.25.4 Recovery Delay
      26. 20.7.26 PCHGC—Pre-ChargingCurrent
        1. 20.7.26.1 Threshold
        2. 20.7.26.2 Delay
        3. 20.7.26.3 Recovery Threshold
        4. 20.7.26.4 Recovery Delay
    8. 20.8  Permanent Fail
      1. 20.8.1  SUV—Safety Cell Undervoltage
        1. 20.8.1.1 Threshold
        2. 20.8.1.2 Delay
      2. 20.8.2  SOV—Safety Cell Overvoltage
        1. 20.8.2.1 Threshold
        2. 20.8.2.2 Delay
      3. 20.8.3  SOCC—Safety Overcurrent in Charge
        1. 20.8.3.1 Threshold
        2. 20.8.3.2 Delay
      4. 20.8.4  SOCD—Safety Overcurrent in Discharge
        1. 20.8.4.1 Threshold
        2. 20.8.4.2 Delay
      5. 20.8.5  SOT—Overtemperature Cell
        1. 20.8.5.1 SOTC Threshold
        2. 20.8.5.2 SOTC Delay
        3. 20.8.5.3 SOTD Threshold
        4. 20.8.5.4 SOTD Delay
      6. 20.8.6  SOTF—Overtemperature FET
        1. 20.8.6.1 Threshold
        2. 20.8.6.2 Delay
      7. 20.8.7  CD—Capacity Degradation
        1. 20.8.7.1 Threshold
        2. 20.8.7.2 Delay
      8. 20.8.8  CFET—CHG FET Failure
        1. 20.8.8.1 OFF Threshold
        2. 20.8.8.2 OFF Delay
      9. 20.8.9  DFET—DFET Failure
        1. 20.8.9.1 OFF Threshold
        2. 20.8.9.2 OFF Delay
      10. 20.8.10 AFER—AFE Register
        1. 20.8.10.1 Threshold
        2. 20.8.10.2 Delay Period
        3. 20.8.10.3 Compare Period
      11. 20.8.11 AFEC—AFE Communication
        1. 20.8.11.1 Threshold
        2. 20.8.11.2 Delay Period
    9. 20.9  PF Status
      1. 20.9.1 Device Status Data
        1. 20.9.1.1  Safety Alert A
        2. 20.9.1.2  Safety Status A
        3. 20.9.1.3  Safety Alert B
        4. 20.9.1.4  Safety Status B
        5. 20.9.1.5  Safety Alert C
        6. 20.9.1.6  Safety Status C
        7. 20.9.1.7  Safety Alert D
        8. 20.9.1.8  Safety Status D
        9. 20.9.1.9  PF Alert A
        10. 20.9.1.10 PF Status A
        11. 20.9.1.11 PF Alert B
        12. 20.9.1.12 PF Status B
        13. 20.9.1.13 PF Alert C
        14. 20.9.1.14 PF Status C
        15. 20.9.1.15 PF Alert D
        16. 20.9.1.16 PF Status D
        17. 20.9.1.17 Fuse Flag
        18. 20.9.1.18 Operation Status A
        19. 20.9.1.19 Operation Status B
        20. 20.9.1.20 Temp Range
        21. 20.9.1.21 Charging Status A
        22. 20.9.1.22 Charging Status B
        23. 20.9.1.23 Gauging Status
        24. 20.9.1.24 IT Status
      2. 20.9.2 Device Voltage Data (at the Time of PF Event)
        1. 20.9.2.1 Cell 1 Voltage
        2. 20.9.2.2 Battery Direct Voltage
        3. 20.9.2.3 Pack Voltage
      3. 20.9.3 Device Current Data
      4. 20.9.4 Device Gauging Data (at the Time of PF Event)
        1. 20.9.4.1 Cell 1DOD0
        2. 20.9.4.2 Passed Charge
      5. 20.9.5 AFE Regs
        1. 20.9.5.1  OCC
        2. 20.9.5.2  OCD1
        3. 20.9.5.3  OCD2
        4. 20.9.5.4  Short Circuit Discharge
        5. 20.9.5.5  Current Discharge Wake
        6. 20.9.5.6  Current Charge Wake
        7. 20.9.5.7  OCC 1 Delay 2
        8. 20.9.5.8  OCC 1 Delay 1
        9. 20.9.5.9  OCD 1 Delay 2
        10. 20.9.5.10 OCD 1 Delay 1
        11. 20.9.5.11 OCD 2 Delay 2
        12. 20.9.5.12 OCD 2 Delay 1
        13. 20.9.5.13 Short Circuit Discharge Delay
        14. 20.9.5.14 Over Temperature Delay
        15. 20.9.5.15 OCD Wake Delay 2
        16. 20.9.5.16 OCD Wake Delay 1
        17. 20.9.5.17 OCC Wake Delay 2
        18. 20.9.5.18 OCC Wake Delay 1
    10. 20.10 Black Box
      1. 20.10.1 Safety Status
      2. 20.10.2 PF Status
    11. 20.11 Gas Gauging
      1. 20.11.1  Current Thresholds
        1. 20.11.1.1 Dsg Current Threshold
        2. 20.11.1.2 Chg Current Threshold
        3. 20.11.1.3 Quit Current
        4. 20.11.1.4 Dsg Relax Time
        5. 20.11.1.5 Chg Relax Time
      2. 20.11.2  Design
        1. 20.11.2.1 Design Capacity mAh
        2. 20.11.2.2 Design Capacity cWh
        3. 20.11.2.3 Design Voltage
      3. 20.11.3  Cycle
      4. 20.11.4  FD
        1. 20.11.4.1 Set Voltage Threshold
        2. 20.11.4.2 Clear Voltage Threshold
        3. 20.11.4.3 Set % RSOC Threshold
        4. 20.11.4.4 Clear % RSOC Threshold
      5. 20.11.5  FC
        1. 20.11.5.1 Set Voltage Threshold
        2. 20.11.5.2 Clear Voltage Threshold
        3. 20.11.5.3 Set % RSOC Threshold
        4. 20.11.5.4 Clear % RSOC Threshold
      6. 20.11.6  TD
        1. 20.11.6.1 Set Voltage Threshold
        2. 20.11.6.2 Clear Voltage Threshold
        3. 20.11.6.3 Set % RSOC Threshold
        4. 20.11.6.4 Clear % RSOC Threshold
      7. 20.11.7  TC
        1. 20.11.7.1 Set Voltage Threshold
        2. 20.11.7.2 Clear Voltage Threshold
        3. 20.11.7.3 Set % RSOC Threshold
        4. 20.11.7.4 Clear % RSOC Threshold
      8. 20.11.8  State
        1. 20.11.8.1  QMax
        2. 20.11.8.2  Update Status
        3. 20.11.8.3  Cell 1 Chg Voltage at EoC
        4. 20.11.8.4  Current at EoC
        5. 20.11.8.5  Average Last Run
          1. 20.11.8.5.1 Avg I Last Run
          2. 20.11.8.5.2 Avg P Last Run
        6. 20.11.8.6  Delta Voltage
        7. 20.11.8.7  Temp
          1. 20.11.8.7.1 Temp k
          2. 20.11.8.7.2 Temp a
        8. 20.11.8.8  Max Avg Last Run
          1. 20.11.8.8.1 Max Avg I Last Run
          2. 20.11.8.8.2 Max Avg P Last Run
        9. 20.11.8.9  SOH FCC Max
          1. 20.11.8.9.1 SOH FCC Max mAh
          2. 20.11.8.9.2 SOH FCC Max cWh
        10. 20.11.8.10 SOH Temp
          1. 20.11.8.10.1 SOH Temp k
          2. 20.11.8.10.2 SOH Temp a
        11. 20.11.8.11 Cycle Count
      9. 20.11.9  Turbo Cfg
        1. 20.11.9.1 Min System Voltage
        2. 20.11.9.2 Ten Second Max C-Rate
        3. 20.11.9.3 Ten Millisecond Max C-Rate
        4. 20.11.9.4 High Frequency Resistance
        5. 20.11.9.5 Reserve Energy %
        6. 20.11.9.6 Turbo Adjustment Factor
      10. 20.11.10 IT-DZT Config
        1. 20.11.10.1  Design Resistance
        2. 20.11.10.2  Pack Resistance
        3. 20.11.10.3  System Resistance
        4. 20.11.10.4  Predict Ambient Time
        5. 20.11.10.5  Ra Filter
        6. 20.11.10.6  Ra Max Delta
        7. 20.11.10.7  Reference Grid
        8. 20.11.10.8  Resistance Parameter Filter
        9. 20.11.10.9  Near EDV Ra Param Filter
        10. 20.11.10.10 Max Current Change %
        11. 20.11.10.11 Resistance Update Voltage
        12. 20.11.10.12 Qmax Delta
        13. 20.11.10.13 Qmax Upper Bound
        14. 20.11.10.14 Term Voltage
        15. 20.11.10.15 Res Relax Time
        16. 20.11.10.16 Term Voltage Delta
        17. 20.11.10.17 Max Simulation Iterations
        18. 20.11.10.18 Simulation Near Term Delta
        19. 20.11.10.19 Fast Scale Start SOC
        20. 20.11.10.20 DeltaV Max Voltage Delta
        21. 20.11.10.21 Load Select
        22. 20.11.10.22 Fast Scale Load Select
        23. 20.11.10.23 Load Mode
        24. 20.11.10.24 User Rate-mA
        25. 20.11.10.25 User Rate-cW
        26. 20.11.10.26 Reserve Cap-mAh
        27. 20.11.10.27 Reserve Cap-cWh
      11. 20.11.11 Smoothing
        1. 20.11.11.1 Smooth Relax Time
        2. 20.11.11.2 Term Smooth Start Cell V Delta
        3. 20.11.11.3 Term Smooth Final Cell V Delta
        4. 20.11.11.4 Term Smooth Time
      12. 20.11.12 Condition Flag
      13. 20.11.13 Max Error
        1. 20.11.13.1 Time Cycle Equivalent
        2. 20.11.13.2 Cycle Delta
      14. 20.11.14 SOH
    12. 20.12 RA Table
      1. 20.12.1 R_a0
      2. 20.12.2 R_a0x
  23. 21Data Flash Access and Format
    1. 21.1 Data Flash Access
      1. 21.1.1 Minimum Voltage
    2. 21.2 Data Formats
      1. 21.2.1 Unsigned Integer
      2. 21.2.2 Integer
      3. 21.2.3 Floating Point
      4. 21.2.4 Hex
      5. 21.2.5 String
  24. 22Data Flash Summary
    1. 22.1 Data Flash Summary - Subject to Change upon FW build details
  25. 23Revision History

11 Charge Current Derating

Overview

The BQ27Z855 linear charger supports charge current derating to protect the device from excessive internal die temperature and to reduce cable or connector losses caused by a large voltage drop between the PACK output and the battery terminals. Two independent derate axes are evaluated each firmware cycle:

  • Temperature Derate — based on the internal die temperature (INT_TEMP). When the die temperature rises above a configured threshold, the charging current requested from the charger is reduced by the corresponding derate percentage.
  • Pack-Bat Derate — based on the voltage difference between the PACK output voltage and the battery voltage (VPACK−VBAT). A large differential indicates significant resistive drop in the charge path. When this differential exceeds a configured threshold, the charging current is derated to reduce power dissipation.

The active derate percentage applied to the charging current is the maximum of the temperature derate and the pack-bat derate at any given moment. The resulting effective charging current is:

Effective ChargingCurrent = ChargingCurrent × (100 − ActiveDerate) / 100

The active derate percentage (0–99%) can be read from ManufacturerAccess() 0x00B5 ChargerStatus() bytes 2–3 (bits 31–16). A value of 0 indicates no derating is active.

6-Entry Stepped Lookup Table

Each derate axis uses a 6-entry stepped lookup table (indices 0–5). Each entry pairs a threshold with a derate percentage. Thresholds must be configured in ascending order (index 0 is the lowest threshold).

Ordinal advancement: The active derate level (ordinal) advances to the next index when the measured value meets or exceeds the threshold at the next level. The ordinal retreats only when the measured value drops below the current threshold minus the configured hysteresis value. This prevents rapid toggling of the derate level near a threshold boundary.

When the measured value falls below threshold index 0, the active derate for that axis is 0% (no derating).

Enable Configuration

Each derate axis is independently enabled by a bit in the Advanced Charge Algorithm > Charger > Configuration register (default 0x0D):

Bit Name Default Description
TEMPDERATE (bit 2) 1 (enabled) Enables temperature-based charge current derating. When set, the Temperature Threshold 0–5 and Temperature Derate 0–5 tables are active.
PACKBATDERATE (bit 3) 1 (enabled) Enables PACK-BAT differential-based charge current derating. When set, the Pack Bat Diff 0–5 and Pack Bat Derate 0–5 tables are active.
Note:

Both derating axes are enabled by default. Set the corresponding bit to 0 to disable a derate axis. Disabling both axes prevents any derating from being applied regardless of temperature or PACK-BAT differential.

Reading the Active Derate Percentage

The currently active derate percentage is readable via ManufacturerAccess() 0x00B5 ChargerStatus(). Starting from firmware version v0.07 (build 8, BMSFW-11843), this command returns 4 bytes instead of 2 bytes:

Bytes (I2C order) Bits Content
Bytes 0–1 (aaAA) 31–16 ChargerStatus bits (LINCHGR, CHGR_DET, LIN, IDON, IDOFF, LINSUPP, LINOFFT). See ManufacturerAccess() 0x00B5 ChargerStatus.
Bytes 2–3 (bbBB) 15–0 Active derate percentage (0–99%). Maximum of temperature derate and pack-bat derate currently applied to ChargingCurrent(). A value of 0 indicates no derating is active.
Note:

Host software reading exactly 2 bytes from MAC 0x00B5 will receive only the ChargerStatus bits and will not receive the derate percentage. Update host software to read 4 bytes from this command.