When is a balcony battery worth it?
Play with the simulation below and see, hour by hour, how much of your solar production gets used with and without a battery.
See below how it changes for your own setup.
Where does a day of sunshine actually go?
One clear day in Athens, second by second. The band is your solar production, split by where each watt ends up; the white line is what your home is using. Press play, drag the chart, or hover any moment for the full breakdown, then change the settings below to match your balcony.
The whole day, added up
Self-consumption — the share of your solar that your home actually uses — is the single number that decides whether a battery pays off.
Without a battery
With a 2 kWh battery
Clear-sky Athens (37.98°N), south-facing railing mount tilted 35°, 400 Wp panels with 12% derate, 800 W inverter cap, battery 90% usable at 95% efficiency each way, €0.223/kWh, exported surplus counted as €0. Household curves are illustrative apartment profiles (≈7–9 kWh/day). A teaching model, not a quote.
Want the exact numbers for your home? Try the payback calculator →