I'm ready to present the first recap of my off-grid energy consumption after one full month. This summary should provide valuable insights into how the system actually performs under real-life conditions.
Since March 5th, we’ve been running the heat pump to warm up the underfloor heating. This was necessary because the furnishing contractors required a constant temperature of at least 20°C for two weeks before laying the tiles. By around March 10th, we had already reached the target temperature.
On March 15th, due to several days of bad weather, the power generator kicked in and ran for about half an hour. Fortunately, the following day brought a significant improvement in sunlight, and although the batteries had been depleted, the photovoltaic system bounced back impressively—producing 9.4 kW from a 10 kWp setup. That’s a strong result, as most systems typically reach only 80–90% of their peak capacity. It’s worth noting that our consumption also included energy used by various power tools—minor, but still something to account for.
On March 15th, due to several days of bad weather, the power generator kicked in and ran for about half an hour. Fortunately, the following day brought a significant improvement in sunlight, and although the batteries had been depleted, the photovoltaic system bounced back impressively—producing 9.4 kW from a 10 kWp setup. That’s a strong result, as most systems typically reach only 80–90% of their peak capacity. It’s worth noting that our consumption also included energy used by various power tools—minor, but still something to account for.
There were also some hiccups. On March 6th, shortly after the heat pump started, the batteries drained completely. The system shut down too late, and by morning there was no energy left to restart. This occurred because the generator’s circuit board had not been properly attached and therefore didn’t start automatically..
March 2025 recap:
Monthly Production: 233.1 kWh
Monthly Energy Discharged: 133 kWh
Monthly Energy Purchased: 0 kWh
Monthly Consumption: -217 kWh
Monthly Energy Charged: -143.6 kWh
Monthly Grid Feed-in: 0 kWh
Conclusions
Conclusions
If there's one thing I’ve learned about PV installations in Poland, it’s this: never take anything for granted. Every building is different, and it’s impossible to predict real energy consumption until the system is up and running—and until your own lifestyle factors are in play. That said, here are a few early conclusions:
- Battery Capacity Needs: If we plan to live here during winter, battery capacity must be increased. Based on March’s data, an additional 2–3 kWh would be helpful. Ideally, adding two new 5 kWh batteries would provide sufficient buffer.
- Energy Efficiency: The house appears to be quite energy-efficient, using 217 kWh in March—comparable to what my family consumes in our current flat.
- Winter Forecasting: I don’t have enough data yet to confidently estimate energy needs from November through February. However, to stay fully independent and avoid daily fuel station visits, we’d likely need to double our current battery capacity.
- Backup Planning: I need to develop a Plan B in case we run out of fuel and the system completely shuts down. A reliable backup is essential. I'm thinking about 2 or 3 new panels placed eastward with according MPPT connected directly into one of the batteries to load it in case there's no voltage in them. I'll think about it when summer ends.
