BMS carrier is the board which is responsible for monitoring and managing the main battery pack. It interfaces with the AFE (analog front end) board and the Current Sense board to get readings from the main pack.
Other Resources:
FWXIV BMS Carrier notes
Operation
BMS carrier sends/receives messages, which help it start up and operate properly.
Startup
Car turns on to power main or power aux, BMS board receives power from Aux
On startup, do all initial checks that are possible
If everything checks out, start transmitting BPS heartbeat to indicate successful startup
Wait for message from Centre Console to close relays
Close relays
Continue to monitor and send BPS heartbeat messages, data, in normal operation
Shutdown
Centre console (when power off is pressed) will send a close relays message
Centre console will cut power to BMS via Power distribution once it has confirmed that relays are closed
Faults
AFEs
Current Sense
Fan Faults
Data Output
(this is just documentation on what was done in FW14, and is subject to change)
BMS Outputs the following over the CAN bus:
cell voltages
cell temperatures
avg current
avg voltage
relay states
fan states
AFEs
The AFEs (analog front end) handle interactions with the main battery pack. There are multiple AFEs (LTC6811 chips) which handle reading cell voltages, reading thermistors to determine cell temperatures, and doing load balancing for the cells. These multiple AFE units are daisy-chained through one SPI interface. This SPI interface is interacted with the same as normal spi, but through hardware is translated to isoSPI and back to SPI for improved reliability.
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