Chevy Volt / Opel Ampera Gen1 BMS
Posted: Fri Jan 17, 2020 7:34 pm
I began to explore the BMS that i got with chrashed Ampera battery.
Battery is 16kWh all in all. It is assembled from 3P 96S 15Ah LG chem cells - 288 total.
They are encased in plastic casing with liquid cooling.
In front of the battery there is a unit which houses two contactors, a liquid heater, fuses and BMS brain unit.
This black box controlls charging relays and contactors. We call it BECM.
Complete BMS system is made of a BECM unit, 4x Slave modules BICM, current sensor and harness to connect them.
I am actually surprised. You can get the cell voltages out of a standalone Volt battery. You have to hook up to the bottom connector of the BECM module inside - connector X1, with the following pins. If you're looking at the factory connector, numbering starts in the top right and moves left, they are the these colours:
1 - Black - Ground
2 - Red - 12V
3 - White/Black - CAN_Low
4 - Light Blue - CAN_High
9 - Black - Ground
14 - Brown/Red - 12V
15 - Orange/Yellow - 12V
16 - Light Green/Light Blue - 12V
BECM will power the slave modules and get voltages from them. Then it will report on its own CAN wires.
BECM CAN bus works on 500kbaud but slave CAN bus works a 125kBaud.
The slave modules on the batteries are wired in a daisy chain so you can put the voltage and CAN on at any point in the chain (though termination should be on the ends)
Battery Harness wire colors:
Gy/Rd 5V power
L-Bu/Gry CAN H
Wh/Ye CAN L
Bk/Vt GND
L-Bu HV Fault signal
I tried to get a BECM report on system fault and it seems that fault signal enters BECM as a pulse from 125kBaud side, but i am not able to pinpoint the actual HVC or LVC signals. They must be transmitted from BECM on vehicle 500kBaud CAN bus lines. Will search more...
Sources
https://www.diyelectriccar.com/forums/s ... 00023.html
https://www.diyelectriccar.com/forums/s ... 946p6.html
https://www.diyelectriccar.com/forums/s ... 01p59.html
http://electricgokart36v.blogspot.com/2 ... or-ev.html
https://www.diyelectriccar.com/forums/s ... ost1050937
Battery is 16kWh all in all. It is assembled from 3P 96S 15Ah LG chem cells - 288 total.
They are encased in plastic casing with liquid cooling.
In front of the battery there is a unit which houses two contactors, a liquid heater, fuses and BMS brain unit.
This black box controlls charging relays and contactors. We call it BECM.
Complete BMS system is made of a BECM unit, 4x Slave modules BICM, current sensor and harness to connect them.
I am actually surprised. You can get the cell voltages out of a standalone Volt battery. You have to hook up to the bottom connector of the BECM module inside - connector X1, with the following pins. If you're looking at the factory connector, numbering starts in the top right and moves left, they are the these colours:
1 - Black - Ground
2 - Red - 12V
3 - White/Black - CAN_Low
4 - Light Blue - CAN_High
9 - Black - Ground
14 - Brown/Red - 12V
15 - Orange/Yellow - 12V
16 - Light Green/Light Blue - 12V
BECM will power the slave modules and get voltages from them. Then it will report on its own CAN wires.
BECM CAN bus works on 500kbaud but slave CAN bus works a 125kBaud.
The slave modules on the batteries are wired in a daisy chain so you can put the voltage and CAN on at any point in the chain (though termination should be on the ends)
Battery Harness wire colors:
Gy/Rd 5V power
L-Bu/Gry CAN H
Wh/Ye CAN L
Bk/Vt GND
L-Bu HV Fault signal
I tried to get a BECM report on system fault and it seems that fault signal enters BECM as a pulse from 125kBaud side, but i am not able to pinpoint the actual HVC or LVC signals. They must be transmitted from BECM on vehicle 500kBaud CAN bus lines. Will search more...
Sources
https://www.diyelectriccar.com/forums/s ... 00023.html
https://www.diyelectriccar.com/forums/s ... 946p6.html
https://www.diyelectriccar.com/forums/s ... 01p59.html
http://electricgokart36v.blogspot.com/2 ... or-ev.html
https://www.diyelectriccar.com/forums/s ... ost1050937