Tools

Industry-standard calculators.
Real formulas. Real results.

Find the right calculator for the questions our specialists field weekly — pipe sizing, storage capacity, electrical conversions and water-quality checks. Sensible defaults, every field editable, every output in the units you work in.

PV array sizing for solar pumps

This tool models the sun as a bell curve across daylight hours, the VFD cut-in dead-band at sunrise/sunset, and the pump's flow-vs-power curve. Stages panel-count → litres/day so you can see the actual return on each extra panel.

Pump rating

Standard IEC motor sizes. Choose 'Other' to type a nameplate kW.

Site location

Annual PSH

5.5 h/day

Winter PSH

4.2 h/day

PSH = day's total irradiance expressed as equivalent full-sun hours (the energy budget). The clock-hour pumping window in the table below is calculated from that budget — it's the time the array's DC output actually exceeds the pump cut-in.

Type to search SA + neighbouring towns. Picks the published winter / annual Peak Sun Hours for that area.

Pump curve · flow at two anchor points

Flow at rated power

L/min

The pump's nameplate flow (Q at full rated kW). Most lodge / borehole pumps are 30–250 L/min.

Flow at 30 % power

L/min @ 30 %

Pump-curve anchor used to fit Q ∝ P^α. Defaults to 55 % of rated, which matches a typical centrifugal under VFD speed control.

Operating-point correction · optional

Catalogue / nameplate flow is given at the pump's best-efficiency point — at one specific head. To match it to your actual site we need two physical numbers from you: the pump's rated head (off the pump curve) and the static head (the vertical lift from your water source up to the discharge, plus outlet pressure if any). Friction loss is computed from the pipe geometry below — you don't have to know it in advance. Total dynamic head = static + friction, and the simulation scales friction with flow at each timestep.

Pump rated head

m head

The head (m) at which the catalogue rated flow is published. On the pump curve, this is the head at the BEP / nameplate point.

Static head

m static

Vertical lift from the water source level up to the discharge level. Add outlet pressure if any (1 bar ≈ 10 m). This is the part of total dynamic head that does NOT change with flow.

Friction loss · from pipe geometry

Single-pipe Hazen-Williams. Friction scales with L, 1/D⁴·⁸⁷ and Q¹·⁸⁵ — a 2 km run can demand a very different array than a 10 m run at the same flow. For multi-tier networks (mainline + sub-main + lateral) use Network friction loss and switch the toggle above to enter it directly.

Pipe length

m

Total run from pump outlet to discharge (single dominant pipe). Borehole-to-tank runs at lodges are typically 50–500 m; municipal trunks 1–5 km.

Inside diameter

mm ID

The INSIDE diameter of the pipe (mm). For HDPE class-10 50 mm OD the ID is ≈ 44 mm; for 63 mm OD ≈ 55 mm. Use the manufacturer's spec — nominal OD over-states ID by 5–15 %.

Material

Hazen-Williams roughness coefficient. HDPE / PVC are smooth (C = 150); galvanised steel ages to ~C = 120; older mild-steel mains drop to C = 100.

Friction at rated flow

0.51m head · auto-applied

50 m of 50 mm ID at C=150, Q=80 L/min

Velocity check

0.679m/s

Within the 0.6–2.5 m/s engineering envelope.

Panel wattage

Pick the panel you can actually source. Wattage is the STC rating on the nameplate.

Daily volume target

L/day target

Optional. Litres needed per day. The table below will mark the smallest panel count that meets this on winter worst-case.

Advanced · controller, efficiency & daylight

System efficiency

%

Umbrella factor: VFD/MPPT, temperature derate, wiring, soiling, mismatch. 75 % is a defensible SA default.

VFD cut-in threshold

% of rated

DC power as % of pump rated below which the pump won't start. Most solar VFD controllers sit in the 20–30 % range.

Peak-power factor

× pump kW

Minimum array kWp expressed as a multiple of pump kW. 1.30× is the standard PV-direct pumping rule.

Daylight · annual avg

h

Sunrise → sunset clock hours. SA latitudes: equinox ≈ 12 h.

Daylight · winter (June)

h

SA winter solstice ≈ 10.0–10.8 h depending on latitude.

Recommended panels

6modules

= 3.3 kWp total

Smallest count that delivers ≥ 20,000 L/day on June worst-case.

Winter delivery

26,149L/day

= 26.1 m³/day

Pump runs 6.89 h of clock-time.

Annual avg delivery

32,521L/day

= 32.5 m³/day·12.8 kWh/day to pump

Pump runs 8.13 h. Typical year-round day.

Winter energy to pump

9.74kWh/day

= 75.9 L/min peak flow

Energy that actually drives water (= ∫ DC kW while pump is on).

Panels → litres · winter worst-case & annual avg

Panels	Array	Winter kWh	Winter L/day	Winter hrs	Annual kWh	Annual L/day	Annual hrs
6Recommended	3.3 kWp	9.74	26,149	6.89 h	12.8	32,521	8.13 h
8	4.4 kWp	12.4	30,437	7.33 h	15.3	36,593	8.63 h
10	5.5 kWp	13.9	33,140	7.77 h	16.7	39,433	9.13 h
12	6.6 kWp	14.8	34,771	7.98 h	17.7	41,164	9.38 h
14	7.7 kWp	15.5	36,111	8.2 h	18.3	42,000	9.38 h
16	8.8 kWp	16	36,739	8.2 h	18.9	43,269	9.63 h
18	9.9 kWp	16.5	37,788	8.42 h	19.4	44,401	9.88 h
20	11 kWp	16.9	38,732	8.64 h	19.8	44,849	9.88 h

Each row is a separate physics simulation: array kWp × half-sine irradiance × pump-curve flow, with the VFD cut-in dead-band at sunrise / sunset taken into account. Notice the diminishing returns — beyond a certain count the controller clips midday excess and extra panels stop paying for themselves.

Reference only — the team of HidroVerse specialists will design the controller, MPPT settings, string layout, combiner box and DC / surge protection that turn this sizing into a working installation.

Industry-standard calculators.
Real formulas. Real results.

Hydraulic

Water quality

Sizing & capacity

Pool & spa

Electrical

Solar

PV array sizing for solar pumps

Brief us on your water needs.

Industry-standard calculators.Real formulas. Real results.

Hydraulic

Water quality

Sizing & capacity

Pool & spa

Electrical

Solar

Brief us on your water needs.

Industry-standard calculators.
Real formulas. Real results.