esphome-jk-bms

ESPHome component to monitor a Jikong Battery Management System (JK-BMS) via RS485

Supported devices

• JK-BD6A17S6P, hardware version 7.2, software version 7.1.0H

Untested devices

• JK-BD6A20S6P
• JK-BD6A24S6P
• JK-BD6A20S10P
• JK-B1A24S15P
• JK-B2A24S20P

Specifications

	JK-BD6A17S6P
Lifepo4 range	14-17S
Li-ion range	13-17S
LTO range	--
Single cell voltage	1-5V
Acquisition accuracy	∓5mV
Continous discharge	60A
Max discharge	120A
Balance mode	active
Balance current	0.6A
Main circuit condition	0.8mOhm
Overcharge protection voltage	2.5-4.25V
Overcharge release	2.5-4.25V
Charging overcurrent protection (adjustable)	1-60A
Charging overcurrent release time (adjustable)	9-120s
Over discharge protection	2.5-4.25V
Over discharge recovery voltage	2.5-4.25V
Discharging overcurrent protection (adjustable)	1-60A
Discharging overcurrent release time (adjustable)	9-120s
Number of temperature tests	3
Temperature protection	Yes
Short circuit protection	Yes
Coulomb counter	Yes
Bluetooth	Yes
GPS	Optional
Communication	CAN (Optional), RS485 (Optional)

Requirements

• ESPHome 1.18.0 or higher.
• Generic ESP32 or ESP8266 board

Schematics

                RS485-TTL
┌──────────┐                ┌─────────┐
│          │<----- RX ----->│         │
│  JK-BMS  │<----- TX ----->│ ESP32/  │
│          │<----- GND ---->│ ESP8266 │
│          │                │         │<-- 3.3V
└──────────┘                └─────────┘

# RS485-TTL jack (JST-SH 1.0mm pinch)
┌─── ─────── ────┐
│                │
│ O   O   O   O  │
│GND  RX  TX VBAT│
└────────────────┘

The RS485-TTL jack of the BMS can be attached to any UART pins of the ESP. A hardware UART should be preferred because of the baudrate (115200 baud).

Request / Response example

-> 4E 57 00 13 00 00 00 00 06 03 00 00 00 00 00 00 68 00 00 01 29

<- 4E 57 01 1B 00 00 00 00 06 00 01
79 2A
01 0E ED
02 0E FA
03 0E F7
04 0E EC
05 0E F8
06 0E FA
07 0E F1
08 0E F8
09 0E E3
0A 0E FA
0B 0E F1
0C 0E FB
0D 0E FB
0E 0E F2
80 00 1D
81 00 1E
82 00 1C
83 14 EF
84 80 D0
85 0F
86 02
87 00 04
89 00 00 00 00
8A 00 0E
8B 00 00
8C 00 07
8E 16 26
8F 10 AE
90 0F D2
91 0F A0
92 00 05
93 0B EA
94 0C 1C
95 00 05
96 01 2C
97 00 07
98 00 03
99 00 05
9A 00 05
9B 0C E4
9C 00 08
9D 01
9E 00 5A
9F 00 46
A0 00 64
A1 00 64
A2 00 14
A3 00 46
A4 00 46
A5 FF EC
A6 FF F6
A7 FF EC
A8 FF F6
A9 0E
AA 00 00 00 0E
AB 01
AC 01
AD 04 11
AE 01
AF 01
B0 00 0A
B1 14
B2 31 32 33 34 35 36 00 00 00 00
B3 00
B4 49 6E 70 75 74 20 55 73
B5 32 31 30 31
B6 00 00 E2 00
B7 48 36 2E 58 5F 5F 53 36 2E 31 2E 33 53 5F 5F
B8 00
B9 00 00 00 00
BA 42 54 33 30 37 32 30 32 30 31 32 30 30 30 30 32 30 30 35 32 31 30 30 31
C0 01
00 00 00 00 68 00 00 54 D1

Registers

RW	Code	Name	Bytes	Type	Info
R	0x79	Individual Cell voltage	3*n	Hex	The first byte is the cell number, the next two bytes is the voltage value MV. When reading all the data at the same time, 0x79 is followed by one byte length data, n as shown above, and then a group of three bytes represents the
R	0x80	Read power tube temperature	2	Hex	0-140 (-40 to 100) The part exceeding 100 is negative temperature, such as 101 is negative 1 degree (100 Benchmark)
R	0x81	Read the temperature in the battery box	2	Hex	0-140 (-40 to 100) The part exceeding 100 is negative temperature, the same as above (100 reference)
R	0x82	Read battery temperature	2	Hex	0-140 (-40 to 100) The part exceeding 100 is negative temperature, the same as above (100 reference)
R	0x83	Total battery voltage	2	Hex	0.01V 3500*0.01=35.00v minimum unit 10mV
R	0x84	Current data	2	Hex	10000 (10000-11000)*0.01=-10.00 A (discharge) (10000-9500)*0.01=5.00 A (charging) Accuracy 10 mA unit: 0.01 A Note: C0:0x01 redefine 0x84 current data, the unit is 10 mA, the highest bit is 0 Means discharging, 1 means charging If discharging 20 A, the data transmitted will be 2000 (0x07D0) If charging 20 A, the transmission data is 34768 (0x87D0)
R	0x85	Battery remaining capacity	1	Hex	SOC, 0-100%,
R	0x86	Number of battery temperature sensors	1	Hex	Two battery temperature sensors
R	0x87	Number of battery cycles	2	Hex
R	0x89	Total battery cycle capacity	4	Hex	Anshi
R	0x8a	Total number of battery strings	2	Hex
R	0x8b	Battery warning message	2	Bitmask	See ^1
R	0x8c	Battery status information	2	Bitmask	0 bit charging MOS tube state 1 on 0 off This is for upload prompt 1 bit discharge MOS tube state 1 on 0 off This is for upload prompts. 2-position balance switch state 1 on, 0 off, this is for uploading prompts 3 battery dropped 1 is normal. 0 is offline, this is the upload prompt, Bits 4-15: reserved example: 00 01: Indicates that the charging MOS tube is turned on
RW	0x8e	Total voltage overvoltage protection	2	Hex	1000-15000 (10 mV) Minimum unit 10mV
RW	0x8f	Total voltage undervoltage protection	2	Hex	1000-15000 (10 mV) Minimum unit 10mV
RW	0x90	Single overvoltage protection voltage	2	Hex	1000-4500 mV
RW	0x91	Cell overvoltage recovery voltage	2	Hex	1000-4500 mV
RW	0x92	Single overvoltage protection delay	2	Hex	1-60 seconds
RW	0x93	Single undervoltage protection voltage	2	Hex	1000-4500 mV
RW	0x94	Monomer undervoltage recovery voltage	2	Hex	1000-4500 mV
RW	0x95	Single undervoltage protection delay	2	Hex	1-60 seconds
RW	0x96	Cell pressure difference protection value	2	Hex	0-1000 mV
RW	0x97	Discharge overcurrent protection value	2	Hex	1-1000 A
RW	0x98	Discharge overcurrent delay	2	Hex	1-60 seconds
RW	0x99	Charging overcurrent protection value	2	Hex	1-1000 A
RW	0x9a	Charge overcurrent delay	2	Hex	1-60 seconds
RW	0x9b	Balanced starting voltage	2	Hex	2000-4500 mV
RW	0x9c	Balanced opening pressure difference	2	Hex	10-1000 mV
RW	0x9d	Active balance switch	1	Hex	0 (off), 1 (on)
RW	0x9e	Power tube temperature protection value	2	Hex	0-100
RW	0x9f	Power tube temperature recovery value	2	Hex	0-100
RW	0xa0	Temperature protection value in the battery box	2	Hex	40-100
RW	0xa1	Temperature recovery value in the battery box	2	Hex	40-100
RW	0xa2	Battery temperature difference protection value	2	Hex	5-20
RW	0xa3	Battery charging high temperature protection value	2	Hex	0-100
RW	0xa4	Battery discharge high temperature protection value	2	Hex	0-100
RW	0xa5	Charging low temperature protection value	2	Hex	-45 /+25 (no reference-signed data)
RW	0xa6	Charging low temperature protection recovery value	2	Hex	-45 /+25 (no reference-signed data)
RW	0xa7	Discharge low temperature protection value	2	Hex	-45 /+25 (no reference-signed data)
RW	0xa8	Discharge low temperature protection recovery value	2	Hex	-45 /+25 (no reference-signed data)
RW	0xa9	Battery string setting	1	Hex	3-32
RW	0xaa	Battery capacity setting	4	Hex	Ah (Amp Hour)
RW	0xab	Charging MOS tube switch	1	Hex	0 (off), 1 (open)
RW	0xac	Discharge MOS tube switch	1	Hex	0 (off), 1 (open)
RW	0xad	Current calibration	2	Hex	100-20000 mA
RW	0xae	Protection board address	1	Hex	is reserved for use when cascading,
RW	0xaf	Battery Type	1	Hex	0 (lithium iron phosphate), 1 (ternary), 2 (lithium titanate)
RW	0xb0	Sleep waiting time	2	Hex	second data, temporarily for reference
RW	0xb1	Low volume alarm value	1	Hex	0-80 %
RW	0xb2	Modify parameter password	10	Hex	is temporarily used as a reference, fix a password,
RW	0xb3	Dedicated charger switch	1	Hex	0 (off), 1 (on)
RW	0xb4	Device ID code	8	Char	Example 60300001 (60-nominal voltage level: defined by the voltage level, for example, 60 is 60V. Series 48 is 48V series; 3-material system: according to the system definition of battery materials such as iron. Lithium code is 1 manganic acid code 2 ternary code 3; 00001-production serial number: according to manufacturing. The Nth group of the model produced by the manufacturer that month is numbered N (for example: a certain type The first group of the number, then N is 00001)) characters
RW	0xb5	Date of manufacture	4	Char	Example 2004-production year: take the last two digits according to the actual production year; list the production in 2020, Battery, year code 20; Production month: 01-12 months;
RW	0xb6	System working hours	4	Hex	is cleared when leaving factory, unit minute
R	0xb7	Software version number	15	Char	NW_1_0_0_200428
RW	0xb8	Whether to start current calibration	1	Hex	1 (Start calibration) 0 (Close calibration)
RW	0xb9	Actual battery capacity	4	Hex	Ah (Amp Hour)
RW	0xba	Manufacturer ID naming	24	Char	See ^2
W	0xbb	Restart the system	1	Hex	1 (Restart the system)
W	0xbc	reset	1	Hex	1 (Restore) (only restore the factory reference parameters)
W	0xbd	Remote upgrade logo	1	Hex	Start of Hex 1 (wait for logo response when issuing documents)
W	0xbe	Battery low voltage turns off GPS	2	Hex	unit: mV ( turn off the power to GPS when low voltage is detected )
W	0xbf	Battery low voltage recovery GPS	2	Hex	unit: mV ( turn on the power to the GPS when the recovery voltage value is detected )
R	0xc0	Protocol version number	1	Hex	Default value: 0x00 0x01: Redefine 0x84 current data, the unit is 10 mA, and the highest bit is 0 for discharging. 1 means charging If discharging 20A, the data transmitted will be 2000 (0x07D0) If charging 20A, the transmission data is 34768 (0x87D0)

*^1: Battery warning message

Bit	Description	Values	Severity
0	Low capacity alarm	1 (alarm), 0 (normal)	warning
1	MOS tube over-temperature alarm	1 (alarm), 0 (normal)	alarm
2	Charging over-voltage alarm	1 (alarm), 0 (normal)	alarm
3	Discharge undervoltage alarm	1 (alarm), 0 (normal)	alarm
4	Battery over temperature alarm	1 (alarm), 0 (normal)	alarm
5	charging overcurrent alarm	1 (alarm), 0 (normal)	alarm
6	Discharge overcurrent alarm	1 (alarm), 0 (normal)	alarm
7	Cell pressure difference alarm	1 (alarm), 0 (normal)	alarm
8	Over-temperature alarm in the battery box	1 (alarm), 0 (normal)	alarm
9	Battery low temperature alarm	1 (alarm), 0 (normal)	alarm
10	Monomer overvoltage alarm	1 (alarm), 0 (normal)	alarm
11	Monomer undervoltage alarm	1 (alarm), 0 (normal)	alarm
12	309_A protection	1 (alarm), 0 (normal)	alarm
13	309_A protection	1 (alarm), 0 (normal)	alarm
14	Reserved
15	Reserved

Example

0x0001 = 00000000 00000001: Low capacity alarm
0x0002 = 00000000 00000010: MOS tube over-temperature alarm
0x0003 = 00000000 00000011: Low capacity alarm AND MOS tube over-temperature alarm

*^2: Manufacturer ID naming (24 chars)

Example value: BT3072020120000200521001 -> BT 3 072 020 12 0000 20 05 21 001

Value	Description	Known values
BT	Product name	BT for battery
3	Battery type	1 (Iron-Lithium), 2 (Mangenese acid), 3 (Ternary code)
072	Voltage level	48V, 60V, 72V
020	Capacity grade	20 for 20AH
12	Cycle life	4 (400 cycles), 12 (1200 cycles)
0000	Manufacturer code
20	Production year	20 (2020), 21 (2021)
05	Production month	1-12
21	Production day	1-31
0001	Production serial number	According to the Nth group of the model produced on the day of the manufacturer’s production date, The number is N (for example: the first group of a certain model, then 001)

References

• https://secondlifestorage.com/index.php?threads/jk-b1a24s-jk-b2a24s-active-balancer.9591/
• https://github.com/jblance/jkbms
• jblance/mpp-solar#112
• https://github.com/jblance/mpp-solar/blob/master/mppsolar/protocols/jk232.py
• https://github.com/jblance/mpp-solar/blob/master/mppsolar/protocols/jk485.py
• https://github.com/sshoecraft/jktool
• https://blog.ja-ke.tech/2020/02/07/ltt-power-bms-chinese-protocol.html