Sungrow SG8.0RS + Tesla Powerwall 2 + Amber + PowerSync + Home Assistant: How I enabled Modbus and achieved inverter curtailment

Sungrow SG8.0RS + Tesla Powerwall 2 + Amber + Home Assistant + PowerSync (Confirmed Working)

After months of trial and error, I've finally managed to get my Sungrow SG8.0RS inverter working with Home Assistant, PowerSync, Amber Electric and a Tesla Powerwall 2.

Hopefully this saves someone else a lot of frustration.

My Hardware

  • Sungrow SG8.0RS inverter
  • Sungrow WiNet-S communication dongle
  • Sungrow 3-Phase Smart Meter
  • Tesla Powerwall 2
  • Amber Electric
  • Raspberry Pi 5
  • Home Assistant
  • PowerSync

Firmware Versions Confirmed Working

WiNet-S

WINET_B000.V042.P001

SG8.0RS

SUNSTONE-S_B000.V001.P049-20251122

The Problem

For a long time I could monitor my system but couldn't properly control it.

Many people (including myself) assumed the SG8.0RS could not be curtailed or controlled properly through Home Assistant and PowerSync.

Modbus appeared unavailable, controls were hidden, and PowerSync could not perform the functions I wanted.

The Breakthrough

The breakthrough came after updating BOTH:

  • WiNet-S firmware
  • SG8.0RS firmware

After the update, additional controls became available in:

  • O&M (Installer) settings
  • End User settings

Important Discovery

Some settings did not appear to save correctly the first time.

I had to repeatedly toggle certain options:

  • On / Off
  • Open / Close
  • Enable / Disable

multiple times before they actually changed state.

After changing them, I saved the settings in the End User menu.

Only after doing this did Modbus and remote control functions become available.

What I Enabled

O&M Controls

Enable installer/O&M access.

End User Controls

Enable user control functions and remote operation settings.

Modbus

Enable Modbus communication and confirm Modbus TCP becomes available.

I verified Modbus communication through Home Assistant.

Results

The following are confirmed working:

:white_check_mark: Home Assistant integration

:white_check_mark: PowerSync integration

:white_check_mark: Tesla Powerwall 2 integration

:white_check_mark: Amber Electric optimisation

:white_check_mark: Remote access via Tailscale

:white_check_mark: Modbus TCP communication

:white_check_mark: Inverter Shutdown

:white_check_mark: Inverter Restore

:white_check_mark: DC Solar Curtailment

:white_check_mark: Export control using Smart Meter feedback

Tesla Powerwall Behaviour

The Powerwall acts as the first buffer.

PowerSync can optimise battery charging and discharging while monitoring:

  • Amber prices
  • Battery SOC
  • Solar production
  • House load

When necessary, PowerSync can also curtail solar generation on the Sungrow side.

Home Assistant Setup

Home Assistant running on:

  • Raspberry Pi 5

Additional software:

  • PowerSync
  • Tailscale
  • Termius

Remote control and monitoring work from anywhere.

My Conclusion

The SG8.0RS CAN be controlled.

The missing piece for me was:

  1. Updating firmware.
  2. Enabling O&M controls.
  3. Enabling End User controls.
  4. Making sure settings actually saved.
  5. Opening Modbus access.
  6. Using a Sungrow Smart Meter.

Once those pieces were in place, PowerSync was able to communicate with the inverter and perform curtailment functions.

Hopefully this helps the next person trying to combine:

  • Sungrow SG8.0RS
  • Tesla Powerwall 2
  • Amber Electric
  • Home Assistant
  • PowerSync

without spending months figuring it out.

Happy to answer questions if anyone is trying to build a similar setup.

Thanks for sharing this, I had most of the pieces working but you covered some things I wasn't aware of.

Curious if PowerSync or Sungrow are doing any energy automation for you, as that gets complicated fast: dynamic tariffs, battery reserve, solar curtailment, and possibly EV charging. The hard part seems to be priority order rather than any single device integration...