Solar + Battery Build Calculator

Click anywhere in the shaded areas to size the cheapest solar + battery build that keeps a constant load powered for your target uptime — based on 19 years of hourly sun data from PVGIS. Sizes and cost are reported per kW of load for the panels, batteries, and solar inverters only. Panels are assumed to lie flat, and inverters are sized at a fixed DC/AC ratio of 2 (1 kW of inverter per 2 kW of panels); solar above the inverter rating is clipped. Soiling is assumed to cost 10% of panel output on average. Inverters are assumed 98.5% efficient, and batteries 85% round-trip efficient (AC to AC), with losses split equally between charge and discharge.

Cost assumptions
Average power on a flat 1 m² panel, day and night, over . Darker is sunnier.
Click a location to begin.

Average year

Each point is the mean across all years () at that hour of the year.