Solar Panel & Inverter Calculator

At 540 Wp per module a 100 kW system needs about 186 panels; at 590 Wp it needs about 170. Higher-wattage modules mean fewer panels, fewer mounting points and less cabling, which is why module selection changes structural cost as much as it changes panel count. The calculator updates all three figures as you change the wattage.

Deliberately. Modules rarely deliver their full rated output — irradiation, temperature and soiling see to that — so sizing the inverter at roughly 85 to 90 per cent of DC capacity keeps it operating in its efficient band for more hours and costs less. The resulting DC-to-AC ratio is shown so you can check it against what a vendor has quoted you.

Around 1.1 to 1.3 suits most Indian C&I rooftops. Below 1.1 you are paying for inverter capacity that will almost never be used. Above about 1.3 you begin clipping meaningful generation on clear days. The right point within that band depends on your site's irradiation profile and whether you are chasing peak output or annual units.

No. It is the working array only. Projects normally carry a small spare stock, and the exact number depends on your O&M agreement and the module warranty terms, so it is agreed at contract stage rather than assumed here.