Solar Pump Sizing For Farm Calculator

Work out solar pump sizing for farm instantly with clear inputs, formula shown and shareable results.

About Solar Pump Sizing For Farm Calculator

Hydraulic energy to lift water is volume x head x 9.81 / 3600 kilowatt-hours. Dividing by wire-to-water efficiency, typically 35-50% for a solar submersible, gives the electrical energy required, and dividing that by peak sun hours gives the array size in kilowatts peak.

Formulas

Hydraulic energy

kWh = volume (m3) x head (m) x 9.81 / 3600

Array size

Array (kWp) = hydraulic kWh / system efficiency / peak sun hours

Worked example

With the default values below, Solar Pump Sizing For Farm Calculator returns Solar Array Size of 1.321. Change any input above and every figure here is recalculated in your browser.

Inputs used

Water Requiredminimum 0.1 m3/day: 40 m3/day
Total Dynamic Headminimum 0.1 m: 30 m
Peak Sun Hoursminimum 0.5 h/day: 5.5 h/day
Pump And Controller Efficiencyaccepts 5–90 %: 45 %

Results

Solar Array Size: 1.321
Hydraulic Energy Per Day: 3.2700
Electrical Energy Per Day: 7.267
Suggested Pump Rating: 1.585

Step by step

1Values used
2Hydraulic energy
3Array size
4Solar Array Size= 1.321
5Hydraulic Energy Per Day= 3.2700
6Electrical Energy Per Day= 7.267
7Suggested Pump Rating= 1.585

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What is total dynamic head?

Static lift from water level to discharge, plus friction losses in pipe and fittings, plus any pressure needed at the outlet. Use the drawdown water level during pumping, not the static level.

Do I need a battery?

Usually not. Solar pumps are best paired with a storage tank sized for a day or two of demand, which is far cheaper than batteries and gives the same security of supply.