HomePage Forums Plugins Support Growatt Inverter + Pylontech Batteries : BMS Comms Guide

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    Growatt does NOT communicate via the CAN port. It communicates via the RS485 port that is positioned below the CAN port on the master battery.

    And in addition to that, it requires a 9600 baud rate, which you can set using the 4 small white dipswitches on the master battery.

    For the Growatt you must set those dipswitches to: 1 0 0 0 (ON OFF OFF OFF)

    When connected to the CAN port and put into Li (L02) mode, the Growatt inverter faults and gives an error 20 and an error 04 constantly.

    When connected to the RS485 port with the dipswitches set to 1000, comms is immediately established and it works as intended.

    Recommended configuration process

    1. Turn inverter on but run off battery only. Disable A/C input and A/C output (use isolator switches if you have them).

    2. Go to setting 5 and select battery type = Li. Then select profile L02 (This is specifically for Pylontech batteries). Push ESC to return to home screen. Go back to setting 5 and verify that it was saved as Li.

    3. Now shutdown the inverter and batteries completely. Turn the batteries off using the on/off flip switch, not just the red button on the master battery.

    4. Now make sure that the end of the comms cable on the battery side (it will probably have a little sticker on it that says BAT) is plugged into the RJ45 port labelled RS485 that is below the CAN port. And also make sure that the other end is plugged into the RJ45 port labelled BMS on the inverter and NOT into the other RJ45 port that is labelled RS485 (Yes, I know, it’s weird, just go with it).

    5. Now set the 4 little white dipswitches to: ON OFF OFF OFF (1000).

    6. Now turn the batteries back on and then turn the inverter back on.

    You should no longer see any fault codes or the red fault light.

    How to tell that the inverter really is communicating with the BMS properly

    1. You should now see a little Li symbol next to the battery icon on the home screen of the inverter, and that Li symbol should NOT be flashing. When it’s not flashing and is solid it means comms is working.

    2. If you go and look at most of the battery values on the status screens or in settings related to battery level (SOC) you should now see percentage values where there were voltage values before. Setting 21 is a good example of that.

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