SAX Power ESS

Battery storage system with integrated grid meter.

Overview

This bundle provides integration with the SAX Power Home Plus ESS (Energy Storage System), a compact residential battery storage solution. The bundle consists of two components that work together to manage battery storage and grid monitoring.

SAX Power Home Plus ESS is suitable for residential solar storage, peak shaving, and home energy management applications.

Supported Devices

SAX Power Home Plus

  • Type: Residential lfp battery storage

  • Capacity: 5,8kWh/7,7kWh

  • Communication: Direct IP communication

  • Typical Use: Residential solar storage, peak shaving

  • Grid Connection: Single-phase

  • Battery Chemistry: Lithium iron phosphate battery

  • Documentation: SAX Power manual

Components

This bundle implements the following OpenEMS Components:

SAX Power ESS

Name: SAX Power ESS

Factory-PID: Ess.SaxPower

Implemented Natures/Interfaces

  • SaxPower

  • ManagedSymmetricEss

  • SymmetricEss

  • OpenemsComponent

  • ModbusComponent

  • ModbusSlave

Description: Core battery management component for the SAX Power ESS. Controls charge/discharge operations, monitors state of charge and battery health. Single-phase operation with configurable capacity and phase selection.

Configuration:

  • id (String): Component ID for unique identification (default: "ess0")

  • alias (String): Human-readable alias for the component

  • enabled (Boolean): Enable/disable this component (default: true)

  • modbus_id (String): ID of Modbus bridge for communication (default: "modbus0")

  • modbusUnitId (Integer): The Unit-ID of the Modbus device (default: 100)

  • phase (SingleOrAllPhase): Phase connection - L1, L2, L3, or ALL (default: L1)

  • timeout (Integer): The time the battery switches to normal mode after receiving no write command (default: 60)

  • Modbus_target (String): Modbus target filter - auto-generated

Due to a firmware error in SAX devices, only the SunSpec protocol supports writing to registers. To use this function, please ensure that at least firmware versions Master V61 and Gateway V54 are installed on your battery. If this is not the case, you will need to update your firmware. You will need to contact the customer support for this.

Also, by default, the battery regulates the power very slowly (about 100 W every 5 seconds). In most cases, I would recommend asking the support to decrease the reaction time.

SAX Power ESS Grid-Meter

Name: SAX Power ESS Grid-Meter

Factory-PID: Ess.SaxPower.Grid-Meter

Implemented Natures/Interfaces

  • SaxPowerEssGridMeter

  • ElectricityMeter

  • OpenemsComponent

  • ModbusComponent

  • ModbusSlave

Description: Grid power monitoring component for SAX Power ESS. Reads grid power consumption/production and monitors grid connection status. Provides visibility into net power flow between grid and home.

Configuration:

  • id (String): Component ID for unique identification (default: "meter0")

  • alias (String): Human-readable alias for the component

  • enabled (Boolean): Enable/disable this component (default: true)

  • type (Enum): Meter type - GRID, PRODUCTION, or CONSUMPTION (default: GRID)

  • modbus_id (String): ID of Modbus bridge for communication (default: "modbus0")

  • modbusUnitId (Integer): The Unit-ID of the Modbus device (default: 100)

  • Modbus_target (String): Modbus target filter - auto-generated