Solar water pump sizing and storage
Size the pump duty, winter PV array and water storage for remote bores and surface-water sites in Australia and New Zealand.
Work from daily water demand to a solar pumping duty
Review the public example, check the hydraulic duty, then confirm the pump and PV arrangement against current manufacturer data.
Grundfos SQFlex / Lorentz PS2
Submersible solar bore pump
These figures come from the Tenselo engine. Every result Tenselo produces shows the inputs it used and the method behind it, so the work can be checked rather than taken on trust.
How the solar water pump calculator works
Enter the required daily water volume, total dynamic head, site location and storage allowance. SOL-006 uses the available solar resource to determine the required pumping rate during the design solar window, then estimates the pump duty and PV array required to deliver the daily volume.
The worked Cressy example uses 10.0 kL/day at 45 m total head and 1.5 kWh/m² of winter peak sun. It returns a 111 L/min pump duty, a 2.69 kWp array and a 15 kL tank buffer. These are static example results; the final design requires the current pump curve, controller limits, bore yield, cable run, array orientation, seasonal solar data and site losses.
Why size water storage with the pump?
Daylight pumping usually stores water in a tank rather than electricity in a battery. The storage allowance must cover the operating schedule, low-sun periods and the consequences of an unavailable pump without exceeding the source yield or site constraints.
What does the Tenselo solar water pump calculator size?
SOL-006 connects daily water demand and total dynamic head to the pump flow, winter solar energy, PV array and tank buffer. Related Tenselo tools cover pump selection, DC cable voltage drop, inverter sizing, PV array sizing and PV string voltage.
Are Tenselo's solar and off-grid calculators written for Australian conditions?
They use metric inputs and include Australian and New Zealand site locations where relevant. The responsible designer must verify the standards, network requirements, manufacturer data and site conditions that apply to the project.
Can I use the solar and off-grid power calculators now?
New applications are reviewed before access is granted. You can start a 14-day free trial application and tell us about your business.
Why it matters on the job
Array sized to winter
PV sized to the worst-month sun so the pump still delivers in July.
Pump matched to the well
Duty and head worked for the bore, with real submersible model lines.
Storage over batteries
Tank buffering sized so you store water, not expensive kWh.
Method & worked example
Size the water reserve separately from the solar array
A sunny-day pump flow does not show whether the system can meet demand through a low-solar period. Start with daily demand and usable water storage.
| Input or step | Value |
|---|---|
| Daily water demand | 12 kL/day |
| Assumed reserve duration | 3 days |
| Required usable reserve | 12 × 3 = 36 kL |
| Nominal tank capacity | More than usable reserve if outlet level or operating limits make water inaccessible |
The three-day duration is an assumption, not a reliability recommendation. Test it against local seasonal weather, allowable interruption and backup supply. Tank inflow, demand changes, evaporation and leakage require a time-based water balance.
Inputs needed for solar pump sizing
Record daily demand, source drawdown, delivery elevation, outlet pressure and pipe losses. Use the selected pump and controller data at that duty, together with seasonal solar availability, shading and electrical losses. Peak sun hours describe equivalent solar energy; they are not automatically the hours a pump runs at full flow.
Use SOL-006 solar pump sizing, then check water storage, pipe losses and operating energy. Water storage and battery storage solve different operating problems and need separate sizing.
Static educational example · Updated 1 October 2026 · Methods and limitations. Project calculations run in the subscription application; New accounts require approval.
6 Solar & Off-Grid Power calculators
Every calculator in this category, by its reference code. Running them requires an approved Tenselo account with access to the relevant calculators.
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SOL-001 Battery & Solar Sizing
Off-grid site: battery bank + PV panels from loads & location
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SOL-002 DC Cable Voltage Drop
12 / 24 / 48 V solar, battery & control wiring: volt drop, % drop and the smallest conductor that meets a target
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SOL-003 Off-Grid Inverter Sizing
Continuous VA + motor-start surge -> inverter kVA, with a surge-rating check
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SOL-004 PV Array Sizing
Module count, array power & area (and string count) for a target kWp or a given area
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SOL-005 PV String Voltage (Temperature)
Cold-morning Voc over-voltage & hot Vmp window check for a series PV string (AS/NZS 5033)
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SOL-006 Solar Water Pump Calculator
Size a solar bore or surface-water pump, PV array and tank buffer from the location, daily volume and total head
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