Solar Water Pump Calculator

Size the array at roughly 1.3 times the pump's electrical rating: a 10 HP pump (~7.5 kW) wants around 10 kWp of panels. The margin covers panel soiling, temperature losses, morning and evening sun, and the controller's conversion losses — an array sized exactly to the motor rating starves the pump for most of the day.

Yes — most solar pumping is battery-free. A VFD-based pump controller converts the array's DC into variable-frequency AC and simply runs the pump faster or slower with the sun. You bank water, not electricity: pump into a tank or reservoir during the day and use it any time. Batteries only enter when you must pump at night.

Most standard three-phase induction pumps run happily from a solar VFD controller — that is the usual industrial retrofit. Dedicated solar pumps (often BLDC) squeeze more water from the same array and matter most at small sizes. For factory ETP/STP transfer, borewells and agri feeders, a controller retrofit on the existing pump is typically the economic answer.

That depends on the total head — how high and how far you are lifting — as much as on power. The same 10 HP pump delivers several times more water at 20 m head than at 80 m. Power sizing is what this tool gives you; the litres-per-day answer needs the pump curve at your head, which we work out from your bore or tank details.