WattWhen vs PVCommander

Stop overpaying for electricity. See exactly when power is cheap, green, or even free. WattWhen is the ultimate energy planner for Germany, helping you navigate the "Solar Paradox." While grid fees are fixed, the stock market price of electricity changes every hour—often dropping to zero or going negative when the sun is shining. WattWhen helps you shift your heavy usage to these "Happy Hours" to save money and reduce grid strain. WHY WATTWHEN? Germany produces record amounts of solar and wind energy. Don't let it go to waste! Whether you have a dynamic electricity tariff (like Tibber or Rabot) or just want to use energy when it's greenest, this app is your daily dashboard. KEY FEATURES: • Live Spot Market Prices: See Day-Ahead prices from the EPEX SPOT market (sourced via SMARD.de) for Germany & Luxembourg. • Shift & Save Scheduler: Drag-and-drop your appliances (Washing Machine, Dryer, Dishwasher) to see the exact cost difference between running them now vs. later. • EV Charging Planner: Optimize your Electric Vehicle charging windows to hit the lowest possible kWh price. • Balcony Solar Sim: Thinking of buying a "Balkonkraftwerk"? Simulate how an 800W panel would lower your specific daily costs. • CO2 Insights: See when the grid is powered by renewables vs. coal. DESIGNED FOR PRIVACY • No account required. • No personal data collection. • All calculations happen locally on your device. DATA SOURCE Market data is provided by the Bundesnetzagentur (SMARD.de) ensuring government-grade accuracy for the DE-LU bidding zone.

PVCommander puts your solar system in your pocket. It is the successor to SMH (Solar Monitoring Hub) and connects to your own solar monitoring device to show live and historical data for your inverter, battery, panels, grid and home. See where your energy is flowing right now with a live animated energy view. Tap the solar panels for per string MPPT detail, the inverter for cluster detail, or the battery for per pack detail. WHAT YOU CAN DO • Live monitoring of solar production, battery state of charge, grid and load • Historical charts for the day, month and year • Push alerts for the events that matter, like low battery, grid loss or high load • Automation rules that switch loads and change inverter settings based on time, battery or solar • Load shedding schedules so you know when the grid goes down, where available • Adjust inverter settings remotely, including charge, output and time slots • Weather based solar forecast for your location • Back up your system to your own Google Drive • Works with many inverter and battery brands