How to use the Water Pump Solar Sizing Calculator
The Formula
Off-grid and agricultural pumps run on predictable daily energy. Undersized arrays leave tanks empty; oversized arrays waste capex. This tool links pump load, lift, and local sun hours to kWp and panel count.
Practical Example
Daily Wh = pump W × run hours × (1 + 0.6% × head in meters). kWp = daily kWh ÷ (peak sun hours × ~80% system efficiency). Panel count = ceil(kWp × 1,000 ÷ module watts). Add 20–30% margin for cloudy days if you need battery backup.
About Water Pump Solar Sizing Calculator
Why size solar for water pumps
Off-grid and agricultural pumps run on predictable daily energy. Undersized arrays leave tanks empty; oversized arrays waste capex. This tool links pump load, lift, and local sun hours to kWp and panel count.
Sizing formula
Daily Wh = pump W × run hours × (1 + 0.6% × head in meters). kWp = daily kWh ÷ (peak sun hours × ~80% system efficiency). Panel count = ceil(kWp × 1,000 ÷ module watts). Add 20–30% margin for cloudy days if you need battery backup.
MPPT vs. PWM
MPPT controllers harvest more energy when array voltage differs from battery voltage or in cold weather. We recommend MPPT for most pump systems above ~150 W or 12 m head; very small 12 V direct pumps may use PWM.
Frequently asked questions
Q: DC pump or AC? A: DC solar pumps skip inverter losses; AC needs inverter surge for motor starts—size accordingly. Q: Is head already in pump watts? A: If your wattage is measured at actual head, reduce the head field toward zero. Q: Battery storage? A: This estimates array for daily energy; add battery bank sizing for night or cloudy autonomy.