Parameters of the BMS

This page shows the parameters of the BMS.

This page will describe the variables of the BMS. There are 3 kind of parameters

1. The BMS variables

2. The BMS configuration parameters

3. The hardware parameters

The BMS variables give the variables of the BMS, like the voltages, currents and temperatures. The BMS configuration parameters are the parameters that could be used to configure the BMS, like the battery parameters, BMS parameters and more. The hardware parameters could be used to keep track of the parameters of the hardware parameters, like the maximum current that is limited by the MOSFETs power dissipation.

In the console (CLI) type "bms get all" to get all the parameters and its current value.

BMS variables list

Parameter	Unit	Datatype	Description	Default	RO/RW	No
c-batt	C	float	The temperature of the external battery temperature sensor	0	RO	0
v-out	V	float	The voltage of the BMS output	0	RO	1
v-batt	V	float	The voltage of the battery pack	0	RO	2
i-batt	A	float	The last recorded current of the battery	0	RO	3
i-batt-avg	A	float	The average current since the last measurement (period t_meas (defaults))	0	RO	4
i-batt-10s-avg	A	float	The 10s rollling average current, updated each 1s with T_meas 1000 (ms)	0	RO	5
s-out	-	bool	This is true if the output power is enabled	0	RO	6
s-in-flight	-	bool	This is true if the system is in flight (with flight-mode-enable and i-flight-mode)	0	RO	7
p-avg	W	float	Average power consumption over the last 10 seconds	0	RO	8
e-used	Wh	float	Power consumption since device boot	0	RO	9
a-rem	Ah	float	Remaining capacity in the battery	0	RW	10
a-full	Ah	float	Full charge capacity, predicted battery capacity when it is fully charged. Falls with aging	4.6	RW	11
t-full	h	float	Charging is expected to complete in this time; zero if not charging	0	RO	12
s-flags	-	uint8_t	This contains the status flags as described in BMS_status_flags_t	255	RO	13
s-health	%	uint8_t	Health of the battery in percentage, use STATE_OF_HEALTH_UNKNOWN = 127 if cannot be estimated	127	RO	14
s-charge	%	uint8_t	Percentage of the full charge 0, 100	0	RO	15
batt-id	-	uint8_t	Identifies the battery within this vehicle, 0 - primary battery.	0	RW	16
model-id	-	uint64_t	Model id, set to 0 if not applicable	0	RW	17
model-name	-	char[32]	Battery model name, model name is a human-readable string that normally should include the vendor name, model name and chemistry	"BMS test"	RW	18
v-cell1	V	float	The voltage of cell 1	0	RO	19
v-cell2	V	float	The voltage of cell 2	0	RO	20
v-cell3	V	float	The voltage of cell 3	0	RO	21
v-cell4	V	float	The voltage of cell 4	0	RO	22
v-cell5	V	float	The voltage of cell 5	0	RO	23
v-cell6	V	float	The voltage of cell 6	0	RO	24
c-afe	C	float	The temperature of the analog front end	0	RO	25
c-t	C	float	The temperature of the transistor	0	RO	26
c-r	C	float	The temperature of the sense resistor	0	RO	27
n-charges	-	uint16_t	The number of charges done	0	RW	28
n-charges-full	-	uint16_t	The number of complete charges	0	RW	29

BMS configuration parameters list

Parameter	Unit	Datatype	Description	Default	RO/RW	No
n-cells	-	uint8_t	Number of cells used in the BMS board	3	RW	30
t-meas	ms	uint16_t	Cycle of the battery to perform a complete battery measurement and SOC estimation can only be 10000 or a whole division of 10000 (For example: 5000, 1000, 500)	1000	RW	31
t-ftti	ms	uint16_t	Cycle of the battery to perform diagnostics (Fault Tolerant Time Interval)	1000	RW	32
t-cyclic	s	uint8_t	Wake up cyclic timing of the AFE (after front end) during sleep mode	1	RW	33
i-sleep-oc	mA	uint8_t	Overcurrent threshold detection in sleep mode that will wake up the BMS and also the threshold to detect the battery is not in use	30	RW	34
v-cell-ov	V	float	Battery maximum allowed voltage for one cell. Exceeding this voltage, the BMS will go to fault mode	4.2	RW	35
v-cell-uv	V	float	Battery minimum allowed voltage for one cell. Going below this voltage, the BMS will go to fault mode (followed by deepsleep after t-fault-timeout)	3	RW	36
v-cell-nominal	V	float	Battery nominal voltage for one cell. will be used for energy calculation	3.7	RW	37
c-cell-ot	C	float	Over temperature threshold for the cells. Going over this threshold and the BMS will go to FAULT mode	45	RW	38
c-cell-ot-charge	C	float	Over temperature threshold for the cells during charging. Going over this threshold and the BMS will go to FAULT mode	40	RW	39
c-cell-ut	C	float	Under temperature threshold for the cells. Going under this threshold and the BMS will go to FAULT mode	(-20)	RW	40
c-cell-ut-charge	C	float	Under temperature threshold for the cells during charging. Going under this threshold during charging and the BMS will go to FAULT mode	0	RW	41
a-factory	Ah	float	Battery capacity stated by the factory	4.6	RW	42
t-bms-timeout	s	uint16_t	Timeout for the BMS to go to SLEEP mode when the battery is not used.	600	RW	43
t-fault-timeout	s	uint16_t	After this timeout, with an undervoltage fault the battery will go to DEEPSLEEP mode to preserve power. 0 sec is disabled.	60	RW	44
t-sleep-timeout	h	uint8_t	When the BMS is in sleep mode for this period it will go to the self-discharge mode, 0 if disabled	24	RW	45
t-charge-detect	s	uint8_t	During NORMAL mode, if the battery current is positive for more than this time, then the BMS will go to CHARGE mode	1	RW	46
t-cb-delay	s	uint8_t	Time for the cell balancing function to start after entering the CHARGE mode	120	RW	47
t-charge-relax	s	uint16_t	Relaxation time after the charge is complete before going to another charge round.	300	RW	48
i-charge-full	mA	uint16_t	Current threshold to detect end of charge sequence	50	RW	49
i-system	mA	uint8_t	Current of the BMS board itself, this is measured (as well) during charging, so this needs to be subtracted	40	RW	50
i-charge-max	A	float	Maximum current threshold to open the switch during charging	9.2	RW	51
i-charge-nominal	A	float	Nominal charge current (informative only)	4.6	RW	52
i-out-max	A	float	Maximum current threshold to open the switch during normal operation, if not overruled	60	RW	53
i-peak-max	A	float	Maximum peak current threshold to open the switch during normal operation, can't be overruled	200	RW	54
i-out-nominal	A	float	Nominal discharge current (informative only)	60	RW	55
i-flight-mode	A	float	Current threshold to not disable the power in flight mode	5	RW	56
v-cell-margin	mV	uint8_t	Cell voltage charge margin to decide or not to go through another topping charge cycle	50	RW	57
v-recharge-margin	mV	uint16_t	Cell voltage charge complete margin to decide or not to do a battery re-charge, to keep the cell voltages at max this much difference with the cell-ov	200	RW	58
t-ocv-cyclic0	s	int32_t	OCV measurement cyclic timer start (timer is increase by 50% at each cycle)	300	RW	59
t-ocv-cyclic1	s	int32_t	OCV measurement cyclic timer final value (limit)	86400	RW	60
c-pcb-ut	C	float	PCB Ambient temperature under temperature threshold	-20	RW	61
c-pcb-ot	C	float	PCB Ambient temperature over temperature threshold	45	RW	62
v-storage	V	float	The voltage what is specified as storage voltage for a cell	3.8	RW	63
ocv-slope	mV/A.min	float	The slope of the OCV curve. This will be used to calculate the balance time	5.3	RW	64
batt-eol	%	uint8_t	Percentage at which the battery is end-of-life and shouldn’t be used anymore Typically between 90%-50%	80	RW	65
battery-type	-	uint8_t	The type of battery attached to it. 0 = LiPo, 1 = LiFePo4, 2 = LiFeYPo4. Could be extended. Will change OV, UV, v-storage, OCV/SoC table if changed runtime	0	RW	66
sensor-enable	-	bool	This variable is used to enable or disable the battery temperature sensor, 0 is disabled, 1 is enabled	0	RW	67
self-discharge-enable	-	bool	This variable is used to enable or disable the SELF_DISCHARGE state, 0 is disabled, 1 is enabled	1	RW	68
flight-mode-enable	-	bool	This variable is used to enable or disable flight mode, is used together with i-flight-mode	0	RW	69
emergency-button-enable	-	bool	This variable is used to enable or disable the emergency button on PTE8	0	RW	70
smbus-enable	-	bool	This variable is used to enable or disable the SMBus update	0	RW	71
uavcan_node_static_id*	-	uint8_t	This is the node ID of the UAVCAN message	255	RW	72
uavcan-es-sub-id*	-	uint16_t	This is the subject ID of the energy source UAVCAN message (1...100Hz)	4096	RW	73
uavcan-bs-sub-id*	-	uint16_t	This is the subject ID of the battery status UAVCAN message (1Hz)	4097	RW	74
uavcan-bp-sub-id*	-	uint16_t	This is the subject ID of the battery parameters UAVCAN message (0.2Hz)	4098	RW	75
uavcan-legacy-bi-sub-id*	-	uint16_t	This is the subject ID of the battery info legacy UAVCAN message (0.2 ~ 1Hz)	65535	RW	76
uavcan-fd-mode*	-	uint8_t	If true CANFD is used, otherwise classic CAN is used	0	RW	77
uavcan-bitrate*	bit/s	int32_t	The bitrate of classical can or CAN FD arbitration bitrate	1000000	RW	78
uavcan-fd-bitrate*	bit/s	int32_t	The bitrate of CAN FD data bitrate	4000000	RW	79

A line means this is not implemented yet. *these parameters will only be implemented during startup of the BMS

BMS hardware parameters list

Parameter	Unit	Datatype	Description	Default	RO/RW	No
v-min	V	uint8_t	Minimum stack voltage for the BMS board to be fully functional	6	RW	80
v-max	V	uint8_t	Maximum stack voltage allowed by the BMS board	26	RW	81
i-range-max	A	uint16_t	Maximum current that can be measured by the BMS board	300	RW	82
i-max	A	uint8_t	Maximum DC current allowed in the BMS board (limited by power dissipation in the MOSFETs)	60	RW	83
i-short	A	uint16_t	short circuit current threshold (typical: 550A, min: 500A, max: 600A)	500	RW	84
t-short	us	uint8_t	Blanking time for the short circuit detection	20	RW	85
i-bal	mA	uint8_t	Cell balancing current under 4.2V with cell balancing resistors of 82 ohms	50	RW	86
m-mass	kg	float	The total mass of the (smart) battery	0	RW	87