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 battery	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
s-out	-	bool	This is true if the output power is enabled	0	RO	5
p-avg	W	float	Average power consumption over the last 10 seconds	0	RO	6
e-used	Wh	float	Power consumption since device boot	0	RO	7
a-rem	Ah	float	Remaining capacity in the battery	2.6	RW	8
a-full	Ah	float	Predicted battery capacity when it is fully charged. falls with aging	4.6	RW	9
t-full	h	float	Charging is expected to complete in this time; zero if not charging	0	RO	10
s-flags	-	uint8_t	This contains the status flags as described in BMS_status_flags_t	255	RO	11
s-health	%	uint8_t	Health of the battery in percentage, use STATE_OF_HEALTH_UNKNOWN = 127 if cannot be estimated	127	RO	12
s-charge	%	uint8_t	Percentage of the full charge 0, 100. This field is required.	55	RO	13
batt-id	-	uint8_t	Identifies the battery within this vehicle, 0 - primary battery.	0	RW	14
model-id	-	int32_t	Model id, set to 0 if not applicable	0	RW	15
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	16
v-cell1	V	float	The voltage of cell 1	0	RO	17
v-cell2	V	float	The voltage of cell 2	0	RO	18
v-cell3	V	float	The voltage of cell 3	0	RO	19
v-cell4	V	float	The voltage of cell 4	0	RO	20
v-cell5	V	float	The voltage of cell 5	0	RO	21
v-cell6	V	float	The voltage of cell 6	0	RO	22
c-afe	C	float	The temperature of the analog front end	0	RO	23
c-fet	C	float	The temperature of the transistor	0	RO	24
c-r	C	float	The temperature of the sense resistor	0	RO	25
n-charges	-	uint16_t	The number of charges done	0	RW	26
n-charges-full	-	uint16_t	The number of complete charges	0	RW	27

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	28
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	29
t-ftti	ms	uint16_t	Cycle of the battery to perform diagnostics (Fault Tolerant Time Interval)	1000	RW	30
t-cyclic	s	uint8_t	Wake up cyclic timing of the AFE (after front end) during sleep mode	1	RW	31
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	32
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	33
v-cell-uv	V	float	Battery minimum allowed voltage for one cell. Going below this voltage, the BMS will go to deep_sleep mode.	3	RW	34
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	35
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	36
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	37
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	38
a-factory	Ah	float	Battery capacity stated by the factory	4.6	RW	39
t-bms-timeout	s	uint16_t	Timeout for the BMS to go to SLEEP mode when the battery is not used.	600	RW	40
t-fault-timeout	s	uint8_t	After this timeout, the battery will leave the FAULT mode and go to SLEEP mode. T	60	RW	41
t-charge-detect	s	uint8_t	During NORMAL mode, if the battery voltage is positive for more than this time, then the BMS will go to CHARGE mode	1	RW	42
t-cb-delay	s	uint8_t	Time for the cell balancing function to start after entering the CHARGE mode	120	RW	43
t-charge-relax	s	uint16_t	Relaxation after the charge is complete before going to another charge round.	300	RW	44
i-charge-full	mA	uint16_t	Current threshold to detect end of charge sequence	50	RW	45
i-charge-max	A	float	Maximum current threshold to open the switch during charging	9**.**2	RW	46
i-out-max	A	float	Maximum current threshold to open the switch during normal operation, if not overruled	60	RW	47
v-cell-margin	mV	uint8_t	Cell voltage charge margin to decide or not to go through another topping charge cycle	30	RW	48
t-ocv-cyclic0	s	int32_t	OCV measurement cyclic timer start (timer is increase by 50% at each cycle)	300	RW	49
t-ocv-cyclic1	s	int32_t	OCV measurement cyclic timer final (timer is increase by 50% at each cycle)	86400	RW	50
c-pcb-ut	C	float	Minimal ambient temperature (measured on the PCB)	-20	RW	51
c-pcb-ot	C	float	Maximal ambient temperature (measured on the PCB)	45	RW	52
v-storage	V	float	The voltage what is specified as storage voltage for a cell	3.8	RW	53
ocv-slope	V/A.min	float	The slope of the OCV curve	0	RW	54
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	55
sensor-enable	-	bool	This variable is used to enable or disable the battery temperature sensor, 0 is disabled, 1 is enabled	0	RW	56
self-discharge-enable	-	bool	this variable is used to enable or disable the SELF_DISCHARGE state, 0 is disabled, 1 is enabled	1	RW	57
uavcan_node_static_id*	-	uint8_t	This is the node ID of the UAVCAN message	255	RW	58
uavcan-subject-id*	-	uint16_t	This is the subject ID of the UAVCAN message	4096	RW	59
uavcan-fd-mode*	-	uint8_t	If true CANFD is used, otherwise classic CAN is used	0	RW	60
uavcan-bitrate*	bit/s	int32_t	the bitrate of classical can or CAN FD arbitration bitrate	1000000	RW	61
uavcan-fd-bitrate*	bit/s	int32_t	the bitrate of CAN FD data bitrate	4000000	RW	62

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	63
v-max	V	uint8_t	Maximum stack voltage allowed by the BMS board	26	RW	64
i-peak	A	uint16_t	Maximum peak current that can be measured by the BMS board	200	RW	65
i-max	A	uint8_t	Maximum DC current allowed in the BMS board (limited by power dissipation in the MOSFETs)	60	RW	66
i-short	A	uint16_t	short circuit current threshold (typical: 550A, min: 500A, max: 600A)	500	RW	67
t-short	us	uint8_t	Blanking time for the short circuit detection	20	RW	68
i-bal	mA	uint8_t	Cell balancing current under 4.2V with cell balancing resistors of 82 ohms	50	RW	69