# BatteryStatusV0 (UORB message)

Battery status

Battery status information for up to 4 battery instances.
These are populated from power module and smart battery device drivers, and one battery updated from MAVLink.
Battery instance information is also logged and streamed in MAVLink telemetry.

[source file](https://github.com/PX4/PX4-Autopilot/blob/main/msg/px4_msgs_old/msg/BatteryStatusV0.msg)

```c
# Battery status
#
# Battery status information for up to 4 battery instances.
# These are populated from power module and smart battery device drivers, and one battery updated from MAVLink.
# Battery instance information is also logged and streamed in MAVLink telemetry.

uint32 MESSAGE_VERSION = 0
uint8 MAX_INSTANCES = 4

uint64 timestamp # [us] Time since system start
bool connected # Whether or not a battery is connected. For power modules this is based on a voltage threshold.
float32 voltage_v # [V] [@invalid 0] Battery voltage
float32 current_a # [A] [@invalid -1] Battery current
float32 current_average_a # [A] [@invalid -1] Battery current average (for FW average in level flight)
float32 discharged_mah # [mAh] [@invalid -1] Discharged amount
float32 remaining # [@range 0,1] [@invalid -1] Remaining capacity
float32 scale # [@range 1,] [@invalid -1] Scaling factor to compensate for lower actuation power caused by voltage sag
float32 time_remaining_s # [s] [@invalid NaN] Predicted time remaining until battery is empty under previous averaged load
float32 temperature # [°C] [@invalid NaN] Temperature of the battery
uint8 cell_count # [@invalid 0] Number of cells


uint8 source # [@enum SOURCE] Battery source
uint8 SOURCE_POWER_MODULE = 0 # Power module
uint8 SOURCE_EXTERNAL = 1 # External
uint8 SOURCE_ESCS = 2 # ESCs

uint8 priority # Zero based priority is the connection on the Power Controller V1..Vn AKA BrickN-1
uint16 capacity # [mAh] Capacity of the battery when fully charged
uint16 cycle_count # Number of discharge cycles the battery has experienced
uint16 average_time_to_empty # [minutes] Predicted remaining battery capacity based on the average rate of discharge
uint16 serial_number # Serial number of the battery pack
uint16 manufacture_date # Manufacture date, part of serial number of the battery pack. Formatted as: Day + Month×32 + (Year–1980)×512
uint16 state_of_health # [%] [@range 0, 100] State of health. FullChargeCapacity/DesignCapacity
uint16 max_error # [%] [@range 1, 100] Max error, expected margin of error in the state-of-charge calculation
uint8 id # ID number of a battery. Should be unique and consistent for the lifetime of a vehicle. 1-indexed
uint16 interface_error # Interface error counter

float32[14] voltage_cell_v # [V] [@invalid 0] Battery individual cell voltages
float32 max_cell_voltage_delta # Max difference between individual cell voltages

bool is_powering_off # Power off event imminent indication, false if unknown
bool is_required # Set if the battery is explicitly required before arming

uint8 warning # [@enum WARNING STATE] Current battery warning
uint8 WARNING_NONE = 0 # No battery low voltage warning active
uint8 WARNING_LOW = 1 # Low voltage warning
uint8 WARNING_CRITICAL = 2 # Critical voltage, return / abort immediately
uint8 WARNING_EMERGENCY = 3 # Immediate landing required
uint8 WARNING_FAILED = 4 # Battery has failed completely
uint8 STATE_UNHEALTHY = 6 # Battery is diagnosed to be defective or an error occurred, usage is discouraged / prohibited. Possible causes (faults) are listed in faults field
uint8 STATE_CHARGING = 7 # Battery is charging

uint16 faults # [@enum FAULT] Smart battery supply status/fault flags (bitmask) for health indication
uint8 FAULT_DEEP_DISCHARGE = 0 # Battery has deep discharged
uint8 FAULT_SPIKES = 1 # Voltage spikes
uint8 FAULT_CELL_FAIL= 2 # One or more cells have failed
uint8 FAULT_OVER_CURRENT = 3 # Over-current
uint8 FAULT_OVER_TEMPERATURE = 4 # Over-temperature
uint8 FAULT_UNDER_TEMPERATURE = 5 # Under-temperature fault
uint8 FAULT_INCOMPATIBLE_VOLTAGE = 6 # Vehicle voltage is not compatible with this battery (batteries on same power rail should have similar voltage)
uint8 FAULT_INCOMPATIBLE_FIRMWARE = 7 # Battery firmware is not compatible with current autopilot firmware
uint8 FAULT_INCOMPATIBLE_MODEL = 8 # Battery model is not supported by the system
uint8 FAULT_HARDWARE_FAILURE = 9 # Hardware problem
uint8 FAULT_FAILED_TO_ARM = 10 # Battery had a problem while arming
uint8 FAULT_COUNT = 11 # Counter. Keep this as last element

float32 full_charge_capacity_wh # [Wh] Compensated battery capacity
float32 remaining_capacity_wh # [Wh] Compensated battery capacity remaining
uint16 over_discharge_count # Number of battery overdischarge
float32 nominal_voltage # [V] Nominal voltage of the battery pack

float32 internal_resistance_estimate # [Ohm] Internal resistance per cell estimate
float32 ocv_estimate # [V] Open circuit voltage estimate
float32 ocv_estimate_filtered # [V] Filtered open circuit voltage estimate
float32 volt_based_soc_estimate # [@range 0, 1] Normalized volt based state of charge estimate
float32 voltage_prediction # [V] Predicted voltage
float32 prediction_error # [V] Prediction error
float32 estimation_covariance_norm # Norm of the covariance matrix

```
