Charge With Your Own Power
If your site has solar panels, you are already generating electricity. But without smart charging, most of that solar energy flows back to the grid — often at a low feed-in rate — while your EVs charge later using expensive grid power.
Stekker flips this equation. By shifting EV charging to the hours when your panels produce the most, you use your own solar energy directly. This is called self-consumption, and it is one of the most effective ways to reduce your energy costs.
How Stekker Knows Your Solar Output
During setup, your solar installation is configured in Stekker with details about your panels: how many, their orientation (azimuth), their tilt angle (declination), and your inverter capacity. This gives Stekker a model of your specific installation.
Combined with weather forecast data, Stekker predicts how much solar power your panels will generate throughout the day — hour by hour. These forecasts are updated regularly as weather conditions change.
Forecast-Based Planning
Rather than reacting to solar production as it happens, Stekker plans ahead. When a vehicle plugs in, the optimization engine already knows:
- When solar production is expected to peak.
- How much energy the vehicle needs before its departure time.
- What other loads and charging sessions are competing for power.
- What electricity prices look like for the rest of the day.
With all of this information, Stekker creates a charging profile that maximizes the overlap between your solar generation and your charging demand. If the sun is expected to shine strongest between 11:00 and 15:00, that is when your vehicle gets the most power.
What Self-Consumption Means for Your Bill
Every kilowatt-hour of solar energy you use directly is a kilowatt-hour you do not buy from the grid. The savings are twofold:
- You avoid the retail electricity price, which includes energy cost, grid fees, and taxes.
- You reduce what you feed back to the grid, where compensation is typically much lower than retail price — especially as net metering schemes are being phased out across Europe.
In many cases, self-consumed solar energy is worth two to three times more than exported energy. Smart charging captures that value automatically.
Balancing Solar With Other Goals
Solar optimization does not operate in isolation. Stekker’s engine considers all optimization goals simultaneously:
- Departure time — If your vehicle must leave at 13:00 but solar peaks at 14:00, Stekker will not wait for solar. Your departure deadline always takes priority.
- Grid limits — Solar charging still respects your contracted grid capacity. If solar production reduces your net grid draw, that frees up room for higher charging power.
- Energy prices — On days when electricity prices drop below your solar value, Stekker might prefer grid power. The engine always picks the lowest-cost combination.
The result is a charging schedule that balances all these factors, not just one.
What Happens on Cloudy Days
Forecasts are not perfect, and weather changes. Stekker handles this through continuous re-optimization:
- If clouds roll in and actual solar production drops below the forecast, Stekker adjusts the charging profile in real time.
- If an unexpectedly sunny afternoon appears, Stekker ramps up charging to capture the extra generation.
- Sensors at your site measure actual solar output, so the engine always knows the real situation — not just the forecast.
This combination of forecasting and real-time measurement means Stekker adapts smoothly to changing conditions throughout the day.
The Role of Sensors
While forecasts drive the plan, sensors verify reality. Sensors installed at your grid connection measure total power flow, including solar generation feeding back into the grid. This gives Stekker:
- Accurate real-time data on actual solar production.
- The ability to detect when forecasts diverge from reality.
- A feedback loop that triggers immediate re-optimization when conditions change.
Together, forecasts and sensors create a system that plans intelligently and corrects quickly. To learn how these optimized schedules reach your charger, see How Stekker Controls Your Charger.
