Solar system sizing calculator
Enter your daily consumption and the sun hours in your area to see how many panel watts you need, with 25% system losses included.
Formulawatts = consumption (Wh) / peak sun hours / 0.75
Your inputs
Sun-hour presets:
Required panel wattage
770 W
2 kWh / 3.5h sun / 75% efficiency
Recommended battery
3000 Wh
1 days autonomy, 80% DoD, 20% margin
Methodology and assumptions
Panel wattage is daily energy required divided by peak sun hours and net system efficiency (75%, i.e. 25% standard losses: cabling, charge controller, temperature). Battery capacity uses daily consumption × autonomy days, divided by depth-of-discharge (80% for LiFePO4) and safety margin (1.2).
Results are estimates and do not replace an energy audit. Check your station’s maximum solar input — a big battery with a small input recharges painfully slowly.
Other solar calculators
Battery capacityTick your appliances and get the Wh capacity you need.Savings and paybackHow much you save per year and how long the investment takes to pay off.Roof area neededHow many square meters of roof you need for the target wattage.Battery charge timeHow many hours to recharge a battery from your panels.