Battery Cell Broadcast Message

For some applications it is necessary to see the real-time voltages from all the cells in a quick and efficient manner. This set of options allows the user to enable a constant CANBUS broadcast message that will sequentially send all the cell voltages within several milliseconds of each other.

NOTE: Due to the high speed of the messages, this should not be enabled on an already crowded CANBUS interface, or on a CANBUS interface that has critical devices on it. It is possible that the increased traffic can reduce the response time of other devices on the selected interface.

This should only be enabled on interfaces with a frequency of 250kBps or higher.

The format for this message is as follows:

Byte 0: Cell ID (8 bit, starting with 0)
Byte 1&2: Instant Voltage (16 bit, unit: 0.1mv)
Byte 3&4: Internal Resistance (15 bit, unit: 0.01mOhm)
Byte 5&6: Open Voltage (16 bit, unit: 0.1mv)
Byte 7: Checksum (8 bit)

Bit 8 in byte #3 is whether or not the cell is shunting (1 indicates current is being shunted, 0 means it is not).

Checksum Calculation:

  1. Take the broadcast ID and add 8 (the length).

  2. Add bytes 0-6 to the value from step 1.

  3. Chop off the least significant 8 bits (effectively turning it into an unsigned byte) and that will be the checksum value.

  4. If the computed checksum does not equal the provided checksum, the values should be discarded.

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