Hi everyone,`
I’m currently integrating a Marstek Jupiter C Plus battery storage system into Home Assistant using an RS485-to-Ethernet Modbus TCP Gateway.
Reading registers works perfectly (e.g., address 13 for current power output, address 25 for monthly export). However, writing values to set the power output dynamically fails:
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Writing target power values to register 16387 (0x4003) via Modbus (FC06 or FC16) has no effect on the battery’s actual output.
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Changing EMS modes via register 16386 (0x4002) beforehand does not release the write lock either.
Has anyone successfully managed to dynamically control the export power of the Marstek Jupiter system via RS485 Modbus TCP in Home Assistant? Is there a known handshake or unlock sequence required by the firmware?
Thanks in advance for any insights!