SolaX Parallel Mode (Master-Slave) Configuration

Overview

This document provides comprehensive guidance for configuring and using SolaX inverters in parallel mode (also called master-slave mode), where multiple inverters work together as a unified system.

What is Parallel Mode?

Parallel mode allows multiple SolaX inverters to operate as a coordinated system: - Master Inverter: Controls the entire system and communicates with Home Assistant - Slave Inverters: Follow the master's commands and report their status to the master - Total System Power: Combined power from all inverters working together

Benefits

Scalability: Increase total system capacity by adding inverters
Efficiency: Master coordinates optimal power distribution
Reliability: System continues working if one inverter fails
Unified Control: Home Assistant sees one integrated system

Hardware Requirements

Supported Models

SolaX GEN4 inverters with parallel mode capability
Properly configured master-slave communication cables
Each inverter must have parallel mode enabled in its settings

Physical Setup

Communication Cables: Special RS485 cables connecting master to slaves
Grid Connection: All inverters connected to the same electrical phase distribution
Battery Banks: Each inverter typically has its own battery bank
PV Arrays: Each inverter has its own PV input connections

Modbus Communication Settings

Baud Rate Configuration (for RS485/RTU connections):

All inverters in parallel mode must use the same baud rate. Check your inverter model:

Inverter Model	Baud Rate	Production Tested	Notes
SolaX X3 Hybrid G4	115200	✅ Yes	Tested in production with Master/Slave and DataHub
SolaX Gen4 & Gen5	19200	-	Standard configuration
SolaX Gen3 (no built-in Ethernet)	115200	-	X1-AC and similar models
SolaX X1 Air, Boost, Mini, Smart, X3 MIC/Pro, X3 Mega	9600	-	Older models
SolaX J1	19200	-	Same as Gen4/Gen5

Recommended Polling Intervals for Parallel Mode: - 🎯 Master Inverter: 5-10 seconds (5s minimum, 10s recommended for stability) - 🎯 Slave Inverters: 10 seconds (recommended default) - ⚠️ Critical: Faster polling increases likelihood of communication issues - 📉 9600 Baud: Never poll faster than 5 seconds

Important Configuration Notes: - ⚠️ All inverters must have matching baud rates - mismatched rates cause communication failures - 🔧 Check via LCD: Verify baud rate in inverter menu (Settings → Advanced Settings → Modbus → Baud Rate) - 🔌 RS485 Adapters: If using RS485-to-Ethernet adapters, ensure adapter baud rate matches inverter settings - 📊 DataHub Systems: For DataHub 1000 connections, 115200 baud has been tested successfully with X3 Hybrid G4

For TCP/IP Connections (Home Assistant ↔ Inverter): - Home Assistant to Inverter: TCP/IP connection (PocketWiFi, DataHub, built-in Ethernet) - Baud rate not applicable for this connection - Port 502 (Modbus TCP standard) - ⚠️ Important: Master/Slave inverters still communicate via RS485 Modbus - All inverters must be configured to the same baud rate - RS485 communication between inverters is independent of TCP/IP - Recommendation: Use 115200 baud for the entire system if supported - Why Higher is Better: Reduces bus congestion and improves parallel mode responsiveness

Modbus Connection Setup

Connection Options

You have two main approaches for connecting to parallel mode systems:

Option 1: Connect to Master Only (Recommended for Remote Control)

Master reports combined PM (Parallel Mode) data for the entire system
Master forwards remote control commands to slave inverters
Single integration instance manages the entire system
Required if you want to use remote control features

Option 2: Connect to Each Inverter Individually

Each inverter can have its own LAN/WAN interface (e.g., separate PocketWiFi dongles)
Create separate integration instances for each inverter
Get detailed individual inverter data
Note: Remote control only works through the master inverter connection
Useful for detailed monitoring and diagnostics

Configuration Steps

Identify the Master Inverter:
Check the inverter display settings
Look for "Parallel Mode" setting showing "Master"
Configure Integration(s):

⚠️ Important: Configuration should be performed via the Home Assistant UI (Settings → Devices & Services → Add Integration → SolaX Modbus). The YAML examples below are for illustration purposes only.

Option 1: Master Only (for remote control)

Via Home Assistant UI: - Go to Settings → Devices & Services - Click "Add Integration" - Search for "SolaX Modbus" - Enter master inverter IP address (e.g., 192.168.1.100) - Select plugin type (e.g., "solax_x1_g4") - Complete setup wizard

YAML example (for reference only): yaml solax_modbus: - name: "SolaX System" host: 192.168.1.100 # Master inverter IP port: 502 modbus_type: "tcp" plugin: "solax_x1_g4"

Option 2: Individual Inverters (detailed monitoring)

Via Home Assistant UI: - Repeat the "Add Integration" process for each inverter - First: Master inverter (192.168.1.100) - Then: Each slave inverter (192.168.1.101, 192.168.1.102, etc.) - Use descriptive names (e.g., "SolaX Master", "SolaX Slave 1")

YAML example (for reference only): ```yaml solax_modbus: - name: "SolaX Master" host: 192.168.1.100 # Master inverter IP port: 502 modbus_type: "tcp" plugin: "solax_x1_g4"

 - name: "SolaX Slave 1"
   host: 192.168.1.101  # Slave 1 inverter IP
   port: 502
   modbus_type: "tcp"
   plugin: "solax_x1_g4"

 # Add more slaves as needed

```

Important: When using Option 2, remote control commands should only be sent to the master inverter entities.

Verify Parallel Mode Detection:
After integration loads, check for parallel_setting entity
Should show "Master" for the connected inverter

Parallel Mode Sensors

When parallel mode is detected, the integration exposes additional PM (Parallel Mode) sensors:

Total System Sensors

pm_total_pv_power: Combined PV production from all inverters
pm_total_inverter_power: Combined inverter power output
pm_total_house_load: Total house consumption (with delta correction)
pm_battery_power_charge: Battery charging power from grid across all units
⚠️ Important: This represents grid contribution to battery charging only
Does NOT include PV contribution to battery charging
Total battery power = pm_battery_power_charge + PV contribution to battery
Example: 28kW charging with 12kW PV → sensor shows ~28kW (grid only), actual total ~40kW

Individual Inverter Sensors

pm_pv_power_1, pm_pv_power_2: PV power per PV input across all inverters
pm_pv_current_1, pm_pv_current_2: PV current per PV input across all inverters
pm_activepower_l1, pm_activepower_l2, pm_activepower_l3: Power per phase across all inverters

Health Monitoring

pm_communication_status: Master-slave communication health
Individual inverter status indicators

Remote Control in Parallel Mode

How It Works

Remote control commands are sent to the master inverter, which: 1. Calculates total system requirements 2. Distributes commands proportionally to slave inverters 3. Monitors and adjusts based on total system feedback

Automatic Detection

The remote control functions automatically detect parallel mode:

if parallel_setting == "Master":
    # Use PM total values for calculations
    pv_power = datadict.get("pm_total_pv_power", 0)
    house_load = datadict.get("pm_total_house_load", 0)
    # ... control logic uses total system values

Control Modes

All remote control modes work in parallel mode: - Power Control: Direct power control for the entire system - Grid Control: Control total grid import/export - Battery Control: Control total battery charging/discharging - Self Use: Minimize total grid usage - Feedin Priority: Maximize total grid export - No Discharge: Prevent discharge across all batteries

For detailed control mode documentation, see: solax-remote-control-redesigned.md

PM House Load Delta Correction

The Problem

SolaX inverters underreport inverter power during remote control operations, particularly during battery charging. This causes calculated house load to appear artificially higher.

The Solution

The integration uses two independent calculation methods:

Inverter Method: pm_inverter_power - grid_power
Direct measurement from inverter perspective
Can be underreported during remote control
Physics Method: pv_power - grid_power - battery_power
Based on energy conservation
More accurate during remote control
Note: Uses battery_power which represents grid-to-battery charging only
This correctly calculates house load since PV-to-battery is already accounted for in the pv_power term

Why the Physics Method Works: The physics method uses pm_battery_power_charge (grid-to-battery only), which is correct because:

House = PV - Grid - Battery_from_grid

PV contribution to battery is implicitly handled since: - pv_power includes all PV production (to house + to battery + to grid) - battery_power only counts grid-to-battery (not PV-to-battery) - The difference correctly isolates house consumption

Delta Correction

delta = physics_method - inverter_method

# Only apply if delta < 25% (avoids transition states)
if abs(delta) <= abs(inverter_method) * 0.25:
    corrected_house_load = inverter_method - (delta / 2)

This ensures accurate remote control calculations by splitting the difference between the two methods.

Troubleshooting

Parallel Mode Not Detected

Symptoms: - No PM sensors appearing - parallel_setting shows "Free" or "Slave"

Solutions: 1. Verify master inverter is correctly configured 2. Check RS485 communication cables between inverters 3. Ensure you're connected to the master (not slave) IP address 4. Restart the integration after verifying settings

Slave Inverter Not Responding

Symptoms: - PM sensors show zero for one or more inverters - Individual inverter status indicates offline

Solutions: 1. Check RS485 cable connections 2. Verify slave inverter parallel mode setting is "Slave" 3. Check master inverter communication status 4. Power cycle the affected slave inverter

Inaccurate House Load Readings

Symptoms: - House load fluctuates wildly during battery charging - Total power balance doesn't add up

Solutions: 1. Delta correction should automatically handle this 2. Check if pm_total_house_load is being used (not individual values) 3. Verify remote control is active when issues occur 4. Review logs for delta correction messages

Remote Control Not Working

Symptoms: - Commands sent but inverters don't respond - Only master responds, slaves don't follow

Solutions: 1. Verify master is executing remote control commands 2. Check slave communication status 3. Ensure all inverters have remote control enabled 4. Check for error messages in Home Assistant logs

Export Limits in Parallel Mode

For parallel mode systems, the default export limit may be too low for combined inverter capacity.

Solution: 1. Enable the config_max_export entity (disabled by default) 2. Set appropriate export limit for your total system capacity 3. May require a Home Assistant restart 4. Verify new limit is reflected in remote control bounds checking

Best Practices

Monitoring

Regular Checks: Monitor PM sensor values for consistency
Communication Health: Watch PM communication status sensors
Individual Status: Check each inverter's operational status
Power Balance: Verify total power adds up correctly

Remote Control

Start Small: Test with low power values first
Monitor Response: Watch all inverters respond to commands
Check Limits: Ensure bounds checking uses total system capacity
Gradual Changes: Avoid rapid power target changes

Maintenance

Firmware Updates: Keep all inverters on same firmware version
Cable Inspection: Regularly check RS485 cable connections
Configuration Backup: Save parallel mode settings
Log Review: Periodically check for communication errors

Technical Details

Communication Protocol

Master uses Modbus TCP/RTU to communicate with Home Assistant
Master uses proprietary RS485 protocol to communicate with slaves
Slaves report status to master at regular intervals
Master aggregates slave data before reporting to Home Assistant

Data Aggregation

The master inverter combines data from all inverters: - Summation: Power values (PV, inverter, battery) - Status: Overall system health and individual inverter status - Coordination: Distributes commands proportionally

Update Frequency

Master polls slaves at ~1-5 second intervals
Master reports to Home Assistant at configured scan interval
Some delay expected between command and all inverters responding

Advanced Configuration

Custom PM Sensors

You can create additional template sensors based on PM data:

sensor:
  - platform: template
    sensors:
      pm_average_pv_per_inverter:
        value_template: "{{ states('sensor.pm_total_pv_power') | float / 2 }}"
        unit_of_measurement: "W"

      pm_system_efficiency:
        value_template: >
          {{ (states('sensor.pm_total_pv_power') | float / 
              (states('sensor.pm_total_inverter_power') | float + 0.01) * 100) | round(1) }}
        unit_of_measurement: "%"

Monitoring Automations

Set up alerts for parallel mode issues:

automation:
  - alias: "Alert PM Communication Failure"
    trigger:
      - platform: state
        entity_id: sensor.pm_communication_status
        to: "Error"
        for: "00:05:00"
    action:
      - service: notify.mobile_app
        data:
          message: "Parallel mode communication error detected"

Additional Resources

Remote Control Details: solax-remote-control-redesigned.md
General FAQ: solax-faq.md
Developer Guide: developer_guide.md

Community Support

If you encounter issues not covered in this guide: 1. Check Home Assistant logs for error messages 2. Review GitHub issues for similar problems 3. Open a new issue with detailed information: - Hardware setup (number of inverters, models) - Configuration details - Log excerpts showing the issue - Screenshots of sensor values

The integration has been tested and validated with parallel mode systems, but configurations can vary. Community feedback helps improve support for all setups.