BYD | Battery–Inverter Communication | No Charging or Discharging

Correct configuration
Check that the system configuration is correct. The latest “BYD Battery-Box Premium HVS & HVM Compatible Inverter List” is available from www.eft-systems.de or www.bydbatterybox.com. Make sure the inverter is configured correctly.

App configuration and firmware
Check that the app configuration was completed successfully and that the battery has the latest firmware.

Check DIP switches
If one or two towers are used, all DIP switches should normally be in the LEFT position, except for configurations such as Kostal PIKO MP plus.

If three towers are connected in parallel, refer to the manual for the correct DIP-switch configuration.

Communication
Check whether the inverter detects the battery correctly and displays parameters such as SOC and battery temperature. If not, check the wiring:

• Confirm the correct pin/cable configuration for the inverter model.
• Replace the communication cable if necessary; minimum CAT5, preferably CAT7 according to the source guidance.
• For SMA and Fronius, check the enable signal required for battery activation.

Depending on the inverter model, one or two of the available communication-connection options may be used. Follow the relevant manual and try the alternative supported connection option if one is available.

Earthing
Connect the battery directly to the building's earthing bar. Do not earth it indirectly via the inverter housing or other devices. Correct battery earthing is important for reliable data communication.

BCU relay closed / output voltage present?
Once communication between battery and inverter has been established, the BCU should close its relay. Only then is output voltage present. Check the output voltage either using the Be Connect app / Be Connect Plus tool or by checking whether the inverter displays the battery voltage correctly.

Restart the complete system in the defined sequence

1. Switch off the battery by holding the power button for 5 seconds.
2. Switch off the inverter DC switch.
3. Switch off the inverter AC circuit breaker.
4. Kostal only: disconnect the PV strings from the inverter.
5. Wait 10 minutes.
6. Switch on the battery by moving the breaker lever up.
7. Kostal only: reconnect the PV strings to the inverter.
8. Switch on the inverter AC circuit breaker.
9. Switch on the inverter DC switch.

If the battery does not switch off after the LED button has been held for 5 seconds and the LED remains on, remove/lift the BCU to prevent further discharge and contact service.