Operation Mode:

1. The BMS sends operating information (Message 1) to charger at fixed interval of 1s. After receiving the message, the charger will work under the Voltage and Current in Message. If the Message is not received within 5s, it will enter into communication error state and stop charging.

CAN Communication

• Speed: 250Kbps

Addresses

Messages

Message 1:

This is the message we send to the charger.

Sender: 0xF4 → BMS

Receiver: 0xE5 → Charger Control System

Rest of the Message: 0x1806

• Priority: 6

• R: 0

• DP: 0 (fixed)

• PF: 6

Message 2

This is the status message charger sends to us.

Sender: 0xE5 CCS

Receiver: 0x50

CAN Communication:

MCP2515

Richard’s Notes

Notes on Charger CAN Comm:

Receiving Data:

·      Every second from BMS with CAN ID 1806E5F4

·      8 bytes of Voltage and Current requested

·      If no valid CAN message, charger stops charging until valid CAN message received

Sending Data:

·      Sends CAN message every second with Voltage, Current, and status information

·      Source Address - BMS – 2244(0xF4)

Stats & Errors:

·      Sends 2 messages, one to BMS and one to CCS

·      Output Voltage and Current (2 Bytes each)

·      Ex: if Byte = 1234 corresponds to 123.4V

·      Status Flags (Byte 5) 

·      Each status takes a bit (uses 5/8 bits)

Pre-Charging Safety Requirements:

·      All Status Flags are 0

·      Received valid CAN message from BMS (or CCS) 5 seconds or earlier

Controlled Relays & Hardware