Solar Water Pump HP Sizing Calculator

A how many solar panels do I need for a 1 HP water pump calculator with panel count and array size. Use the free Solar Water Pump HP Sizing Calculator below — enter your values and get instant results, right in your browser. Array (kW) = pump watts × 1.3 ÷ 1000 (30% margin for starting current and losses). Panels = array watts ÷ panel wattage, rounded up. A 1 HP (746W) pump needs 746 × 1.3 = 970W of panels → 2 × 550W panels (1,100W).

How to use the Solar Water Pump HP Sizing Calculator

Running a tube-well or house water pump on solar is one of the best farm investments in Pakistan — but the panels must cover the motor's starting surge, not just its running watts. This how many solar panels do I need for a 1 HP water pump calculator sizes the array at 130% of the pump rating (covering surge, heat derating, and dust) and converts it into a panel count for common wattages. Size it right and the pump starts reliably even on hazy mornings.

  1. Select your pump size from the dropdown — 1 HP (746W) is the standard house tube-well pump.
  2. Select the panel wattage you plan to buy (550W is the current market standard).
  3. Click Calculate to see the required solar array in kW and the panel count.
  4. Round the panel count UP and confirm your mounting structure fits that many panels.
  5. Pair the array with a solar VFD/pump inverter rated for your pump's HP — panels alone cannot start a motor smoothly.

Formula

Array (kW) = pump watts × 1.3 ÷ 1000 (30% margin for starting current and losses). Panels = array watts ÷ panel wattage, rounded up. A 1 HP (746W) pump needs 746 × 1.3 = 970W of panels → 2 × 550W panels (1,100W).

Worked example

For a 1 HP (746W) water pump: array = 746 × 1.3 ÷ 1000 = 0.97 kW. With 550W panels that is 970 ÷ 550 = 1.76 → 2 panels (1,100W total). A 2 HP (1492W) pump needs 1.94 kW → 4 × 550W panels (2,200W). Always round up — an undersized array stalls the pump on cloudy mornings.

Frequently asked questions

Two 550W panels (1,100W total) comfortably run a 1 HP (746W) pump through a solar VFD. The 30% extra covers starting surge, panel heat derating, and dust.

Yes — daytime direct-drive via a solar pump inverter (VFD) is the standard setup and needs no batteries. The pump simply runs slower on cloudy moments. Batteries are only needed if you must pump at night.

AC pumps with a solar VFD are cheaper, easier to service, and available in every HP size in Pakistan. DC pumps are slightly more efficient but cost more and have limited local service. Most installers recommend AC + VFD.

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