Sigenergy ESS Max Charging/Discharging Limit Entities Not Writable

[discipleofnagash]

Hey, I have the following problem when setting up my integration - this is a summary from Claude Code:

number.sigen_plant_ess_max_charging_limit and number.sigen_plant_ess_max_discharging_limit cannot be written to. They remain stuck at 0.0 kW despite:

• Being enabled in the entity registry
• Having set_value_fn defined in code
• Automations triggering successfully
• Manual Developer Tools → Services calls

What We Verified

1. No inverter-level alternatives - Only plant-level entities exist for these limits (checked code + modbus register definitions)
2. Entities are enabled - disabled_by: null in entity registry
3. Write function exists in code (number.py):
   set_value_fn=lambda coordinator, _, value: coordinator.async_write_parameter(
   "plant", None, "plant_ess_max_charging_limit", value
   )
4. Modbus register defined (modbusregisterdefinitions.py):
   "plant_ess_max_charging_limit": ModbusRegisterDefinition(
   address=40032,
   count=2,
   register_type=RegisterType.HOLDING, # Should be writable
   data_type=DataType.U32,
   gain=1000,
   unit=UnitOfPower.KILO_WATT,
   applicable_to=["hybrid_inverter"],
   )
5. Other entities work:
   - select.sigen_plant_remote_ems_control_mode - writable ✓
   - number.sigen_plant_grid_export_limitation - holds value (10.0 kW)
   - number.sigen_plant_ess_charge_cut_off_state_of_charge - holds value (100%)

I tried to set this via:

• automation
• UI
• Developer tools

[gcoan]

Predbat relies on your inverter integration working properly

Sorry this is a question for the sigenergy modbus integration as to why these are not writable, not Predbat

[discipleofnagash]

OK, will raise an issue there - for Predbat, how necessary is it to set these values for Predbat to work effectively?

[gcoan]

OK, will raise an issue there - for Predbat, how necessary is it to set these values for Predbat to work effectively?

its not essential, predbat by default will always charge and discharge at your inverter's max rate, the inverter charge rate is principally only used for slow rate charges if you have enabled the Predbat low rate charge option, so don't turn that on, and predbat won't try to use it

The other area charge and discharge rates are used are for freeze charge and freeze discharge operations where predbat wants to hold the battery at the current level, running off solar/grid. These are only used if the rates make it favourable (e.g. if you are on Agile). You can disable these options and predbat can operate fine without it for basic charging/discharging