Overview
I’ve developed an enhanced Home Assistant automation for optimizing solar water heater control using Victron ESS data combined with real-time weather station measurements. The system significantly improves upon basic solar forecasting by incorporating local weather conditions.
System Setup
Hardware:
- Victron MultiPlus II GX
- Victron battery system (5kWh LiFePO4)
- 2.8kW solar array
- Electric water heater (controllable via Home Assistant)
- Ecowitt weather station with solar irradiance sensor
- Home Assistant with Victron integration
Key Improvements
Weather Data Integration:
- Real-time solar irradiance (W/m²) vs forecast-only approach
- UV index for additional solar intensity validation
- Wind speed (improves panel cooling efficiency)
- Rain detection for automatic power reduction
- Temperature compensation for panel efficiency
Enhanced Algorithm:
- Hybrid forecast combining base predictions with real-time weather correction
- 5-tier strategy system (MINIMAL → SUPER_AGGRESSIVE)
- Dynamic temperature targets based on actual conditions
- Weather optimization factor: 0.2-1.3x base forecast
Results
Measurable Improvements:
- Forecast accuracy: +15-20% (especially during variable weather)
- Response time to weather changes: 2-5 minutes vs 30+ minutes
- Energy efficiency: +10-15% through better condition matching
- Reduced manual interventions: ~70% fewer adjustments needed
Example Correction:
anonymous_yaml_code.txt (26,6 KB)