Grundfos has been building off-grid water supply systems since 1980, and its solar range is an ecosystem rather than a list of pumps: SQFlex submersibles with their control units for villages, farms and lodges, and SP or CR pumps driven by the RSI solar inverter for large-scale demand. This guide maps the whole system, so you can name exactly the components your project needs. SINES Export supplies the complete range wholesale, worldwide.

The SQFlex platform

SQFlex is a complete water supply system built around the SQF submersible pump. The range combines two hydraulic technologies on the same motor: helical rotor pumps for high heads and small flows, the classic deep-borehole profile, and centrifugal pumps (3" and 4") for larger flows at lower heads. Across the range, the performance envelope reaches roughly 250 m of head and up to 18 m³/h of flow, which covers villages, schools, farms, game reserves and floating installations on ponds and lakes.

Every SQF pump is available in two stainless steel grades: the standard version in AISI 304 and the N version in AISI 316 for aggressive or brackish water. The pump ships as a complete unit with its cable, water level electrode and cable guard.

One motor, any power source

The MSF 3 permanent-magnet motor is the heart of the system. Its built-in electronics accept anything from 30 to 300 VDC (solar arrays, batteries) or 90 to 240 VAC (generator, mains), with no wiring polarity to observe and no external starter box. The electronics carry the intelligence of the system:

• MPPT: on DC supply, the duty point follows the maximum power of the array continuously.
• Dry-running protection: a water level electrode on the cable stops the pump when the level reaches it, and restarts it five minutes after the well recovers.
• Overload and over-temperature protection: the motor reduces speed under excessive load instead of burning out, and stops above 85 °C to restart at 75 °C.
• Voltage protection: out-of-range voltage stops the pump; normal supply restarts it. Transients up to 6 kV are handled, with external lightning protection recommended in areas with high lightning intensity.

System combinations

The same pump builds seven documented system architectures. The control components decide what the system can do:

The control units in two sentences each

• IO 50: the on/off switch box of solar systems. Cuts the array from the pump for service or when no water is needed.
• CU 202: the status, control and communication unit. It talks to the pump through the power cable itself, no extra wires down the borehole, connects the level switch, and displays operation, input power and alarms (dry running, overvoltage, overtemperature, overload).
• IO 101 / IO 101 B: the changeover boxes for hybrid systems, switching the pump between the array and a backup generator. The B version covers the 2.5 kW motor.

Know your water before you order

SQF pumps are built for clean, thin, non-aggressive liquids, and the documented limits matter for pump life:

Accessories complete the installation: solar cables, submersible drop cable with KM termination kits, cable clips and straining wire, flow sleeves for cooling in large-diameter wells, and zinc anodes for aggressive water. All are listed in the sizing we return.

Beyond SQFlex: SP pumps and the RSI inverter

When a village network or an irrigation scheme outgrows the SQFlex envelope, the architecture changes rather than the supplier. A standard three-phase Grundfos SP submersible, the all-stainless workhorse of borehole pumping, or a CR multistage surface pump takes the hydraulic duty. The Renewable Solar Inverter (RSI) drives it from the array: 2.2 to 37 kW, IP66 for outdoor mounting, advanced MPPT that tracks temperature and panel conditions, and a setup wizard preconfigured for Grundfos MS submersible motors. DC from the array or three-phase AC from a generator or the grid, on the same unit.

This is the architecture behind solar centre pivots, large drip stations and town water supply, and it retrofits existing SP boreholes without touching the pump. Our guides on pressurised irrigation and diesel replacement cover the use cases.

Proven in the field

In Terdjun, Indonesia, one SQFlex lifting from 40 m with a 900 W array delivers up to 5,000 litres a day to an overhead tank, serving a community of 18,000 through water points. On Mount Elgon, Uganda, two SQFlex in spring-fed wells ended a daily uphill walk to a waterfall for smallholder coffee farmers; the installation is community-owned and locally operated.

Ordering the right reference

SQF type keys read naturally once decoded: in SQF 5A-7, the first figure is the rated flow in m³/h and the second the number of stages; helical rotor models such as SQF 1.2-2 follow the same logic, and an N suffix selects the 316 stainless variant. In practice you do not need to decode anything: send us head, daily demand and location, and our team returns the exact pump, control unit, array and accessories from the current Grundfos range. The full documentation is available on our SQFlex product page, including the official data booklet.

The Grundfos solar range at SINES Export

Frequently asked questions