Innovative technology for solar-powered water pumps

Posted on Jan 16, 2020

With the increased interest and move toward living ‘off-the-grid’ with solar-powered technology, more and more products are popping up within this realm. In the water and irrigation industry, manufacturers are trying to develop and produce various ‘plug-and-play’ solar-powered pumps. However, these solutions aren’t as simple in application as they are in theory.

As we are not directly involved with the manufacturers of solar-powered pumps at Elsumo, we don’t have the opportunity to manufacture our own solar solution. Instead, we have come up with an innovative new concept to assist in the application of solar-powered pumps. Meet the 21K Solar Ready Motor Controller.

The 21K Solar Ready Motor Controller is one of the newest products within the Elsumo range. The 21K series inverters are specially designed for solar pumping applications. Compared with existing solar pumping inverters, the 21K series improves functionality and performance as well as broadens voltage windows and power ranges.

How do standard, traditional solar-powered water pumps work?

Essentially, traditional solar-powered pumps are driven by solar energy as opposed to grid electricity or diesel. When sunlight falls on the solar panels, it produces a direct current which then feeds the motor to pump out the water. Solar water pumping involves a solar submersible pump, pump switch solar panels and the necessary fittings and accessories.

An electricity booster is used to get the current provided by the solar panels to drive the submersible motor pump. Water is then pumped and stored in a reservoir to be used when needed.

In traditional water pumps, the technology of the pump is manufactured in the pump itself. This means that when the pump breaks, the entire contraption needs to be replaced. This results in an extremely expensive and time-consuming process. The chances of a pump breaking a second time is also increased after work has been done to it. Meaning, that the owner will likely have to reinvest in the entire operation of getting the solar-powered pump installed again.

As borehole pumps are 50 - 200/300 meters below ground, they require specialist work to fix them should something break. The high cost of repairs of borehole pumps is therefore understandable. This was one of the main reasons why we developed the 21K controller.


How does Elsumo’s 21K Solar Ready Motor Controller work?

Elsumo's 21K Solar Ready Motor Controller has the solar-powered technology placed in a stand-alone box that is separate from the pump. This ensures that the functional technology of the solar device is not tied to the pump itself. 

The equipment that converts the solar energy into power for the normal pumps is above ground and easily accessible for anybody to work on or replace if required. Therefore, when the pump fails or needs to be replaced, the replacement value is far less than what the initial capital expense was. 

The 21K controller is primarily applied to borehole pumps. Elsumo also has a range of borehole pumps available - suitable for a variety of different needs and uses.

So, who can best make use of the 21K controller?

The 21K controller is not all that suitable for household pumps. While it can be fitted onto any water pump, its application is not as cost-effective for the final user when it comes to the household borehole pump category.

Elsumo's 21K Solar Ready Motor Controller is cost-beneficial for pumps anywhere from 1.5 kilowatts all the way to 45 kilowatts in capacity.

  • 45-kilowatt applications, roughly 80 - 90%, include the majority of applications of the light industrial and industrial agricultural sectors when it comes to borehole pumping. 

  • 1.1-kilowatt and below are more household applications of solar energy. These are very small and should rather use a purpose-built plug-and-play solar pump.


The 21K controller is better suited to light industrial or agricultural markets. Within these environments, using the 21K controller offers a substantial financial saving if used or implemented on a larger scale. 

The 21K controller abides by the NEMA Standard. This standard determines the connection between the pump and the motor - which are two standalone products. All NEMA products are interchangeable with other NEMA products. Users can use the 21K controller from Elsumo with their existing NEMA Standard product that they already use to pump water. This will then give them the option to operate the pump via solar or via the Eskom grid.

21K Solar Ready Motor Controller Product Features

  • Voltage supported: 230V Single Phase and 400 V Three Phase.

  • Power range: 0.4kW to 37kW.

  • High degree of protection including PV over-voltage, PV polarity warning and auto protection against over-temperature.

  • Advanced MPPT algorithms, ensuring solar power tracking efficiency up to 99%.

  • Drives 2.2kW and lower can be configured with the boost module, allowing for low voltage requirements and a reduction in PV panels.

  • The 21K series can auto-switch between solar input and grid input by configuring the boost module or auto-switching add-on for 24-hour operational requirements.

  • Remote attendance through the GPRS module add-on, monitoring and controlling via mobile application. Users are able to purchase an add-on when purchasing the pump. They can then control the solar-powered pump via an app on their phone.

  • The 21K MCC is housed in an IP54 protected enclosure.


In addition to solar-powered pumps, Elsumo is one of Southern Africa’s leading service providers, suppliers and distributors of comprehensively tested, high-quality borehole, booster, drainage and sewage pumps.


Our team of professionals at Elsumo are available to guide you through the process of buying and installing your 21K Solar Ready Motor Controller. Visit our showrooms in Cape Town to discuss your product requirements, call us, or fill in our contact form and we’ll respond to your query.