Seplos BMS v3

Description of Seplos BMS v3 protocol.

Note. the info in this github is mainly extracted from the Seplos application, and from decoding the traffic from the app.

The 'formal' description is here BMS3.0 Modbus-RTU Protocol.pdf

Modbus RTU

Seplos BMS v3 uses modbus RTU protocol for reading and writing the values and settings as seen in the BMSSudio app The individual BMSses can be addressed by the modbus Client Id. (minus 1: Client 1 in software = client id 0 in modbus)

Writing to the SPA & SCA registers will change the settings of the BMS

Settings: speed: 19200 8N1

Main blocks

Block	Adres	Length	len(hex)	Type	Description
PIA	0x1000	18	0x12	registers	Pack Info A: Basic status info
PIB	0x1100	26	0x1A	registers	Pack Info B: Cell voltage and temperatures
PIC	0x1200	144	0x90	bits/coils	Pack Info C: Cell & other Alarms
SPA	0x1300	106	0x6A	registers	System Parameters A: Settings
SFA	0x1400	80	0x50	bits/coils	System Function A: Overall alarms
SCA	0x150D	13	0x0D	registers	System Control A: FET and onther status & setting
HIA	0x1600	39	0x27	registers	History Info
VIA	0x1700	51	0x33	registers	Version info A: Manufacturer, product and serialnumber info
PCA	0x1800	19	0x23	registers	Protocol control

Request made by Seplos software and example response

client.read_input_registers(0x1700, 0x33, slave=0):
response: [22618, 18477, 17772, 25955, 21605, 25448, 8259, 28462, 11340, 29796, 16973, 21297, 13907, 12848, 12353, 11603, 20528, 13634, 0, 0, 12595, 21328, 12341, 16946, 13105, 12594, 13872, 12342, 12546, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
response (hex): 585a482d456c65635465636820436f2e2c4c7464424d53313653323030412d5350303542003133535030354232333131323630303633000000000000000000000000
string: XZH-ElecTech Co.,LtdBMS16S200A-SP05B13SP05B2311260063

client.read_input_registers(0x1301, 0x01, slave=0):
response: [16]
response (hex): 10

client.read_input_registers(0x1000, 0x12, slave=0):
response: [5236, 1301, 3800, 30400, 64, 125, 1000, 2, 3272, 2837, 3275, 3268, 2845, 2831, 0, 180, 180, 1000]
response (hex): 1474515ed876c0407d3e82cc8b15ccbcc4b1db0f0b4b43e8

client.read_input_registers(0x1100, 0x1a, slave=0):
response: [3273, 3273, 3268, 3272, 3274, 3274, 3275, 3275, 3274, 3273, 3273, 3270, 3271, 3271, 3270, 3272, 2842, 2833, 2831, 2845, 2731, 2731, 2731, 2731, 2833, 2829]
response (hex): cc9cc9cc4cc8ccaccaccbccbccacc9cc9cc6cc7cc7cc6cc8b1ab11b0fb1daabaabaabaabb11b0d

client.read_input_registers(0x1300, 0x6a, slave=0):
response: [4, 16, 5400, 5600, 5400, 5760, 4800, 4640, 4800, 4320, 3400, 3500, 3400, 3650, 3100, 2900, 3100, 2700, 2000, 1000, 500, 203, 205, 210, 100, 300, 300, 65333, 65331, 65326, 100, 65186, 300, 65236, 106, 600, 5, 3000, 205, 10, 3500, 3400, 1500, 1000, 800, 200, 30, 3201, 3231, 3231, 3281, 2781, 2751, 2731, 2631, 3231, 3281, 3281, 3331, 2761, 2631, 2731, 2581, 3201, 3231, 3281, 3331, 2761, 2731, 2731, 2631, 3581, 3681, 3581, 3831, 2831, 2731, 3231, 2731, 10, 3400, 50, 30, 960, 150, 100, 70, 50, 30400, 30400, 3800, 48, 60, 240, 10, 7, 0, 13, 0, 500, 300, 5760, 180, 65356, 5, 8]
response (hex): 410151815e01518168012c0122012c010e0d48dacd48e42c1cb54c1ca8c7d03e81f4cbcdd26412c12cff35ff33ff2e64fea212cfed46a2585bb8cdadacd485dc3e8320c81ec81c9fc9fcd1addabfaaba47c9fcd1cd1d03ac9a47aaba15c81c9fcd1d03ac9aabaaba47dfde61dfdef7b0faabc9faabad48321e3c09664463276c076c0ed8303cf0a70d01f412c1680b4ff4c58

client.read_input_registers(0x1500, 0x04, slave=0):
response: [59399, 776, 4141, 7710]
response (hex): e807308102d1e1e

client.read_coils(0x1200, 0x90, slave=0):
response: [False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, True, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, True, True, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False]

client.read_coils(0x1400, 0x50, slave=0):
response: [True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, False, False, True, False, False, False, False, False, False, False, True, True, True, True, True, True, True, False, True, True, True, True, False, True, False, False, True, True, True, True, True, False, False, True, True, True, True, True, False, False, False, False, True, True, False, False, False, True, True, False, True, True, True, True, False, True, True, False]

Excel

Excel file with the tables available here Seplos BMS v3 modbus registers.xlsx

Warning

Note: I'm not affiliated to Seplos in any way!

This info is explicitly provided “AS IS” without express or implied warranties, guarantees, or guarantees of correctness. So USE THEM AT YOUR OWN RISK! Don't complain if you broke your BMS.

marcelrv/seplosBMSv3