BMS Communication Decoded

	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	P	Q	R	S	T	U	V	W	X	Y	Z	AA	AB	AC	AD	AE	AF	AG	AH	AI	AJ	AK	AL	AM	AN	AO	AP	AQ	AR
1								Start	Code	Status	Length	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	Checksum		End
2		Protocol	Asynchronous serial interface					DD	A5	0	1E	0F	66	0F	63	0F	63	0F	64	0F	3E	0F	63	0F	37	0F	5B	0F	65	0F	3B	0F	63	0F	63	0F	3C	0F	66	0F	3D	F9	F9	77
3		Baud Rate	9600 baud								30
4		#Start bits	1
5		#Data bits	8
6		#Stop bits	1
7		Parity	None					Start	Code	Status	Length	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	Checksum		End
8								DD	A5	0	1B	17	0	0	0	2	D0	3	E8	0	0	20	78	0	0	0	0	0	0	10	48	3	0F	2	0B	76	0B	82	FB	FF	77
9		the serial interface is : TTL voltage, 5V									27	total voltage		current		Residual capacity		Nominal capacity		Cycle times		Manufacture Date		Balanced state, low and high				Protection state		Software version	Rem. SOC	MOSFET	S rating	#ofNTC	NTC 1		NTC 2
10										Units-->		Unit 10mV		Unit 10mA		Unit 10mAh		Unit 10mAh													Percent				0.1 K		0.1 K
11	Host sent									Decoded Val-->		58.88V		0 A		7.2Ah		10Ah		Zero cycles		Too	Lazy	No balancing occuring				No faults		1.6	72	11	15	2	293.4K		294.6K
12	start	status	Command code	length	data	checksum	end
13	0xdd	0xA5 --read	register address	data length, excluding itself	Data content, if length is 0, here skipped	(data + length + command code) checksum, then Complement, then add 1, high bit first, low bit last	0x77
14	0xdd	0x5A --write	register address	data length, excluding itself	Data content, if length is 0, here skipped
15			read 03: Read basic information and status
16			read 04: Read the battery voltage
17			read 05: Read the BMS hardware version number
18	The host computer sends read basic information command (0x03)
19	0xdd	0xa5	0x03	0	--	checksum	0x77
20	BMS response：
21	0xdd	0xa5	status，0 is correct，	data length, excluding itself，(response write command, the lenth is 0)	Data content, if length is 0, here skipped	checksum	0x77
22			if error return 0x80	0	Data content, if length is 0, here skipped	checksum	0x77
23
24		Data content	byte size	Explain
25		total voltage	2BYTE,Unit 10mV，high byte first
26		current	2BYTE，Unit 10mA,high byte first
27		Residual capacity	2BYTE，Unit 10mAh,high byte first
28		Nominal capacity	2BYTE，Unit 10mAh,high byte first
29		Cycle times	2BYTE
30		Date of manufacture	2BYTE	eg: 0x2068,the date is the lowest 5 bit：0x2028&0x1f = 8; month is （0x2068>>5）&0x0f= 0x03 mean March ;year is 2000+ (0x2068>>9) = 2000 + 0x10 =2016;
31		Balanced state low	2byte	Each bit indicates that each cell is balanced, 0 is off, and 1 is on		1S to 16S
32		Balanced state high	2byte	Each bit indicates that each cell is balanced, 0 is off, and 1 is on		17S to 32S, the maximum is 32S
33		Protection state	2byte	Each bit represents a protection state, 0 is unprotected, 1 protection, see details
34		Software version	1byte	0x10 represents version 1.0
35		RSOC	1byte	Indicates the percentage of remaining capacity
36		MOSFET control status	1BYTE	MOSFET status indication, bit0 indicates charging, Bit1 indicates discharge, 0 indicates MOS closed, and 1 indicates open
37		Battery serail number	1byte	Battery serail number, eg: 8S.
38		NTC quantity N	1byte	NTC quantity
39		NTC content	2*N，Unit 0.1K，high bit first	Using absolute temperature transmission, 2731+ (actual temperature 10), 0 degrees = 2731, 25 degrees = 2731+2510 = 2981
40
41	Protection state：
42		bit0	Single overvoltage protection
43		bit1	Single undervoltage protection
44		bit2	Whole group overvoltage protection
45		bit3	Whole group undervoltage protection
46		bit4	(Charge) over temperature protection
47		bit5	(Charge) under temperature protection
48		bit6	(discharge) over temperature protection
49		bit7	(discharge) under temperature protection
50		bit8	(charge) over current protect
51		bit9	(discharge) over current protect
52		bit10	short protect
53		bit11	Front detection IC error
54		bit12	Software lock MOS
55		bit13~bit15	Reserved
56
57
58	Read 0x04 Reg, read the single voltage
59	0xdd	0xa5	0x04	0	--	checksum	0x77
60	BMS response：
61	0xdd	0xa5	status，0 is correct，	data length, excluding itself，(response write command, the lenth is 0)	Data content, if length is 0, here skipped	checksum	0x77
62			if error return 0x80	0	Data content, if length is 0, here skipped	checksum	0x77
63
64		Data length	The data length is the number of battery strings multiplied by 2
65		first cell voltage	2Byte,Unit is mV，high bit first
66		。。。。	。。。。。
67		Nth cell voltage	2Byte,Unit is mV
68
69
70	Read 0x05 register contents, read the hardware version number of the BMS, the longest support 31 characters, through the host computer equipment model to write product model
71	0xdd	0xa5	0x05	0	--	checksum	0x77
72	BMS response：
73	0xdd	0xa5	status，0 is correct，	data length, excluding itself，(response write command, the lenth is 0)	Data content, if length is 0, here skipped	checksum	0x77
74					Data content, if length is 0, here skipped
75
76		Data length N	Device Type Name Length
77		BYTE0	The first character of the ASCII code	For example, the hardware version is LH-XXXX, then the length is 7, byte0 = 'L'
78		。。。
79		BYTE(N-1)
80	communication date
81	Host sent：	DD A5 03 00 FF FD 77
82	BMS response：	DD A5 00 1B 17 00 00 00 02 D0 03 E8 00 00 20 78 00 00 00 00 00 00 10 48 03 0F 02 0B 76 0B 82 FB FF 77
83
84
85	Host sent：	DD A5 04 00 FF FC 77
86	BMS response：	DD A5 00 1E 0F 66 0F 63 0F 63 0F 64 0F 3E 0F 63 0F 37 0F 5B 0F 65 0F 3B 0F 63 0F 63 0F 3C 0F 66 0F 3D F9 F9 77
87
88
89	Host sent：	DD A5 05 00 FF FB 77
90	BMS response：	DD A5 00 0A 30 31 32 33 34 35 36 37 38 39 FD E9 77 --Represents its hardware version number:0123456789ýéw
91
92
93
94
95
96
97
98
99
100