What is EOS Connect?

Integration and control platform that connects your energy hardware with optimization engines

Introduction

EOS Connect is an open-source integration and control platform for intelligent energy management. It acts as the orchestration layer between your energy system (solar panels, battery storage, inverters, EV chargers) and external optimization backends.

Important Understanding: EOS Connect does not perform optimization calculations itself. Instead, it:
  • Collects data from your devices (battery SOC, PV production, load consumption)
  • Retrieves forecasts (PV generation, electricity prices, weather)
  • Sends all data to an external optimization engine (EOS or EVopt)
  • Receives optimization results back
  • Controls your devices based on those results (inverter, battery, EV charger)
  • Provides monitoring and manual control via web dashboard and APIs

The actual optimization calculations are performed by:

  • Akkudoktor EOS (default) - Full-featured optimization engine - GitHub
  • EVopt - Lightweight, very fast alternative - GitHub
Think of it this way: EOS Connect is like a smart home hub that translates between your devices and a powerful optimization brain running separately.

How It Works

System Architecture

EOS Connect operates in a continuous optimization cycle:

  1. Data Collection: Gathers current system state (battery SOC, PV production, load consumption)
  2. Forecast Integration: Retrieves PV forecasts, electricity price forecasts, and weather data
  3. Optimization Request: Sends all data to EOS/EVopt server for calculation
  4. Control Execution: Receives optimization results and controls devices (battery charging, EV charging modes)
  5. Monitoring & Publishing: Provides real-time data via web dashboard, MQTT, and REST API
EOS Connect Process Flow

Figure: EOS Connect process flow diagram

Timing: The optimization cycle runs every refresh_time minutes (default: 3 minutes) with configurable time frame granularity (15 minutes or hourly).

Core Features

Battery Management

SOC Monitoring

Real-time State of Charge tracking with remaining energy calculation

Charge/Discharge Control

Automated modes: grid charging, PV-only, discharge allowed, idle

Dynamic Charging Curve

SOC-based power reduction (100% → 5% as battery fills)

Temperature Protection

Automatic power reduction in extreme cold/heat (-30°C to +70°C)

Dynamic Price Calculation

Analyzes charging history to determine real cost of stored energy

Smart Sensor Detection

Automatically detects battery/grid sensor polarity to ensure correct PV vs Grid attribution

Efficiency Settings

Configurable charge/discharge efficiency for accurate calculations

Temperature-Based Protection Details

When a battery temperature sensor is configured, EOS Connect applies intelligent power reduction to protect your battery:

Temperature Range Charging Power Purpose
< 0°C 5-7.5% Prevents lithium plating in LiFePO4 batteries
0-15°C Gradual increase Safe warm-up phase
15-45°C 100% (SOC-based only) Optimal operating range
45-60°C Gradual reduction Heat protection
> 60°C 5-7.5% Critical temperature protection
Example: At -2°C with 51% SOC, a 10 kW battery would charge at only ~0.65 kW instead of the configured maximum, protecting against cold damage.

Solar Forecasting

Multiple provider support for accurate PV generation predictions:

Provider Description Requirements
Akkudoktor Default, free, comprehensive forecasts Location, tilt, azimuth, power
Solcast High accuracy, commercial provider API key, resource ID (10 calls/day limit)
OpenMeteo Weather-based forecasting Location, system specs
Forecast.Solar Free solar forecasting Location, basic system info
EVCC Use existing EVCC forecasts Running EVCC instance

Multi-Installation Support

Configure multiple PV installations with different orientations:

  • South-facing roof (180°, 25° tilt, 5 kW)
  • East garage (90°, 15° tilt, 2.5 kW)
  • West carport (270°, 10° tilt, 3 kW)

EOS Connect aggregates all forecasts for total system prediction.

Cost Optimization

Dynamic Electricity Pricing

Supports multiple price providers for real-time market rates:

  • Tibber: Scandinavian/European dynamic pricing
  • smartenergy.at: Austrian market prices
  • Stromligning.dk: Danish electricity pricing
  • Fixed 24h: Custom hourly price array
  • Default: Uses Akkudoktor pricing data

Price Modifiers

  • Fixed Adder: Add fixed costs (grid fees, taxes) in ct/kWh
  • Relative Multiplier: Apply percentage markup (e.g., 5%)
  • Feed-in Price: Set your solar export compensation rate
  • Negative Price Switch: Optional: don't pay when prices go negative

Battery Price Calculation (LIFO)

EOS Connect can analyze your charging history to determine the real cost of energy stored in your battery:

  1. Scans last 48-96 hours of power data
  2. Identifies charging events (battery power > threshold)
  3. Attributes energy to either:
    • Grid charging at market price
    • PV surplus at €0 (free solar energy)
  4. Uses Last-In-First-Out (LIFO) valuation for current SOC
  5. Updates optimizer with real battery energy cost
Smart Decision: If you charged your battery from the grid at €0.30/kWh, the optimizer knows not to discharge it when prices are only €0.25/kWh.

Integration Capabilities

Smart Home Platforms

Home Assistant

  • MQTT Auto Discovery
  • Sensor integration
  • Control via entities
  • Native add-on available

OpenHAB

  • Item-based integration
  • MQTT publishing
  • MQTT Auto Discovery (via MQTT binding)
  • REST API access
  • Full sensor support

Inverter Control

Fronius GEN24 Support:

  • Enhanced Interface (Default): Automatic firmware detection, universal compatibility
  • Legacy Interface: Available for corner cases
  • Supported Actions:
    • Grid charge power setting
    • Discharge control
    • SOC monitoring
    • Real-time status

EVCC External Battery Control:

  • Universal interface for all EVCC-supported inverters
  • Battery management without direct inverter connection
  • Note: Dynamic max charge power not currently supported by EVCC

API-Only Mode:

  • Disable direct inverter control
  • Get optimization results via MQTT/REST API
  • Implement control in your own automation

Electric Vehicle Charging (EVCC)

Modes & Control

  • PV Mode: Charge only from solar surplus
  • Min+PV Mode: Minimum grid + solar surplus
  • Fast Charge: Maximum power from grid
  • Off: No charging

Multi-EVCC Support

Control multiple EVCC instances:

  • Home wallbox (main garage)
  • Guest wallbox (driveway)
  • Workshop charger

Integration with Optimization

EOS Connect coordinates battery and EV charging:

  • Prioritizes PV surplus distribution
  • Avoids simultaneous grid charging
  • Respects battery SOC limits
  • Considers electricity price forecasts

Optimization Backends

Akkudoktor EOS (Default)

  • Full-featured: Complex optimization algorithms
  • Comprehensive: Considers all system parameters
  • Flexible: Highly configurable
  • Server: Runs on port 8503
  • GitHub: Akkudoktor-EOS/EOS

EVopt (Lightweight)

  • Fast: Very quick optimization calculations
  • Lightweight: Lower resource requirements
  • Simple: Easier to set up and maintain
  • Server: Runs on port 7050
  • Source: Available via EVCC discussions
Choose Your Backend: Configure via eos.source in config.yaml (eos_server or evopt)

⏱️ Time Frame & Refresh Configuration

Time Frame (Optimization Granularity)

Backend-Specific Capabilities:

  • EOS Server: Only supports 3600 seconds (hourly). 15-minute intervals are not available with this backend.
  • EVopt: Supports both 3600 (hourly) and 900 (15-minute). Use 900 for more precise, dynamic optimization.

Misconfiguration Handling: If you mistakenly set time_frame: 900 with EOS server, it will be automatically corrected to 3600 at startup with a warning message.

Refresh Time

How often EOS Connect sends optimization requests:

  • Default: 3 minutes
  • Recommended Range: 1-5 minutes
  • Considerations: More frequent updates = more API calls to EOS server
Note: Solcast users should use longer refresh times (15+ minutes) due to API rate limits (10 calls/day). EOS Connect automatically extends intervals to 2.5 hours when Solcast is configured.

Benefits Summary

Cost Savings

Minimize electricity bills by optimizing when to charge from grid and when to use battery

Self-Sufficiency

Maximize PV self-consumption, reduce grid dependency

Battery Health

Protect your investment with intelligent charging curves and temperature protection

Automation

Set it and forget it - automatic optimization every few minutes

Insights

Understand your energy system with detailed monitoring and analytics

Flexibility

Easy integration with existing smart home systems and custom automation

Web Dashboard

EOS Connect provides a comprehensive web interface for real-time monitoring and control:

EOS Connect Web Dashboard

Figure: EOS Connect web dashboard showing real-time energy management

Dashboard Features

Main Dashboard

Real-time overview of PV, Load, Battery, and Optimization states with dynamic charts

Battery Overview

Real-time battery status including charge power, temperature monitoring with thermal protection indicators, historical charging sessions, and cost analysis. Includes mobile-responsive temperature display with color-coded status indicators.

Log Viewer

Real-time application logs with component-based filtering

Manual Controls

Override system modes and set charging parameters directly

Next Steps

Ready to get started? Choose your path:

Installation Guide →

Install EOS Connect on your system

Configuration →

Learn how to configure all features

Advanced Features →

Explore API, MQTT, and automation