Battery Not Responding (CAN)

What does 51 mean?

The connected battery, which is expected to communicate via CAN bus, is not responding to queries from the charger. This prevents the charger from obtaining critical battery data (e.g., SoC, voltage, temperature) or controlling the charging process, leading to a shutdown.

• A disconnected or physically damaged CAN bus cable between the charger and the battery's BMS (Battery Management System).
• A faulty battery BMS or its integrated CAN communication module.
• Incorrect CAN bus termination (missing or incorrect resistance) or an incorrect CAN bus ID/addressing setting.
• The battery is powered off, in a deep sleep state, or its BMS is not active.

Click steps to track your progress.

1. 1

   Verify the physical connection and integrity of the CAN bus cable between the charger and the battery's communication port.

2. 2

   Check if the battery's BMS or communication module is powered on and functioning (e.g., indicator LEDs, if present).

3. 3

   Inspect CAN bus termination resistors at both ends of the bus and confirm correct CAN bus addressing or ID settings.