How to Size a Solar Water Pump System: The Complete Guide

Proper system sizing is the foundation of a successful solar water pump installation. An undersized system will not meet water demands; an oversized system wastes money. Follow this guide to get it right.

Step 1: Determine Daily Water Demand

For drinking water: 20-50 liters per person per day
For livestock: Cattle 50L/day, Sheep 10L/day, Poultry 0.3L/day
For irrigation: Depends on crop type, climate, and irrigation method. Drip irrigation typically requires 3-8 mm/day.

Step 2: Calculate Total Dynamic Head

TDH = Vertical Lift + Friction Losses + Required Pressure. Measure the vertical distance from the water source to the discharge point. Add 10-15% for friction losses in properly sized pipes.

Step 3: Determine Available Solar Resource

Look up the Peak Sun Hours (PSH) for your location. This is the equivalent number of hours at 1000 W/m² solar irradiance. Most tropical and subtropical regions have 4-6 PSH daily.

Step 4: Calculate Required Power

Using the formula: Pump Power (W) = (Flow Rate x TDH x Gravity) / (Pump Efficiency x 3600)

For a system delivering 5000 liters/day at 30m TDH with 50% pump efficiency:
Power = (5 x 30 x 9.81) / (0.5 x 3600) x 1000 = 818W

Step 5: Size the Solar Array

Solar Panel Power = Pump Power / (Controller Efficiency x PSH)

With 818W pump, 95% controller efficiency, and 5 PSH:
Array = 818 / (0.95 x 5) = 172W

Add a 25% safety margin: 215W. Round up to standard panel configurations.

Remember: Always have KINBO engineers verify your calculations. Professional system design ensures decades of reliable operation.