This guide explains how to match a solar trailer to a pumping job, how to size it, and how to handle cloudy days and night-time demand.
Typical pumping jobs
Common applications include borehole pumps for livestock and irrigation, surface pumps moving water between ponds and tanks, dewatering of excavations and small pits on construction and mining sites, and water supply for remote camps. Each has a different pattern: some need water every day at a steady rate, others need large volumes for a few weeks.
Start by writing down how much water is needed per day, from what depth or height, and over how many weeks. That tells you whether a trailer suits the job and how big it must be.
Pump and drive choices
Many solar pumping systems use variable speed drives that let the pump run faster when the sun is strong and slower when it is weak, so the pump moves water all day instead of stopping when power drops. Solar pump controllers and drives designed for this purpose can run standard AC pumps from a solar array.
Choose the pump for the head and flow, then size the solar array and drive for the pump. Pumps with high starting currents may need soft starting or a battery buffer so the trailer can start them reliably.
Sizing from water volume
The energy needed depends on the volume of water and the total head, including friction losses in pipes. Calculate the daily energy, then compare it with the trailer’s expected daily output for the site and season. Our guide to daily kWh from a solar trailer explains how output varies with location and weather.
Size for the worst month in which the water is needed, not the annual average. Irrigation demand is often highest in hot, sunny months, which helps; dewatering demand may peak in the rainy season, when solar output is lower.
Store water or store energy
Where water can be pumped into a tank or reservoir during the day and used later, the tank acts as storage and the system may need little or no battery. Water storage is usually simpler and cheaper than batteries. For livestock or camp supply, a few days of tank storage covers cloudy spells.
Dewatering is different. Water keeps flowing into the excavation day and night, so the pump may have to run after dark. That calls for battery storage on the trailer or a backup generator. The battery storage guide covers the options.
Hybrid backup
For critical pumping, such as dewatering where flooding would stop work, combine the solar trailer with a small diesel or gas generator. The controller runs the pump on solar when available and starts the generator only when the sun and batteries cannot keep up. Fuel use falls sharply compared with a generator-only setup.
Make sure the controller manages the changeover automatically and that the generator is sized for the pump’s starting current.
Siting and moving the trailer
Place the trailer where the panels have clear sun for most of the day, as close as practical to the pump to keep cable runs short. On construction sites, check that the trailer does not block plant movement and is protected from vehicles.
Moving between boreholes or work areas is the point of a trailer, so plan the cable and pipe connections for quick disconnection. Secure the trailer against theft and vandalism; see site security for solar trailers for practical measures.
Controls and monitoring
Level switches in tanks and sumps start and stop the pump automatically, preventing dry running and overflow. Remote monitoring shows pump hours, water level and trailer output, so the operator knows whether the system is keeping up without visiting the site.
Protect pumps from dry running and over-temperature. A pump that runs dry in a remote borehole can be destroyed before anyone notices.
Water quality and pump protection
Sand and silt in borehole or dewatering water wear pump impellers and seals quickly. Use pumps suited to the water quality, fit screens or filters where practical, and check flow and current regularly for signs of wear. Dewatering pumps on construction sites often handle very dirty water and need robust designs and frequent inspection.
Record pump current along with flow. A rising current at the same flow often signals wear or blockage before the pump fails.
Maintenance
Solar trailers need little maintenance, but pumping sites are often dusty. Clean panels regularly, check cables and connectors after each move, and inspect batteries and controllers in hot weather. Pumps need their own maintenance according to the manufacturer’s schedule.
Keep a simple log of water pumped and energy produced. If water output falls while solar output stays steady, the pump or the borehole needs attention.
About the hybrid team
Pumping duty is one of the most common loads our hybrid engineers size relocatable solar for. Expertise for this page: the USP&E hybrid power engineers, who design solar, battery and generator systems for remote, agricultural and industrial sites. USP&E carries EPC and O&M responsibility on its own balance sheet, not as a middleman, with 24+ years in the field, 150+ power projects in 45+ countries and 25,000 MW contracted since 2002. Learn about our hybrid power systems.
Offices: Colorado Springs (1755 Telstar Dr, Suite 300), Knoxville (800 S Gay St, Suite 700), London (162-168 Regent Street), Johannesburg (22 Kildoon Rd, Bryanston), Cape Town (31 Brickfield Road, Woodstock) and China (No. 1 Ningzhou Road, Wuxi). Regions: USA | AFRICA | UK | UAE | CHINA. ISO 9001 and ISO 45001 certified.
Questions about solar pumping trailers
Can a mobile solar trailer run a water pump?
Yes. With a suitable solar pump controller or variable speed drive, a trailer can run many borehole and surface pumps directly from its panels.
Do I need batteries for solar pumping?
Not always. If water can be stored in a tank, the tank acts as storage. Dewatering and night-time demand usually need batteries or a backup generator.
How do I size a solar trailer for pumping?
Calculate daily water volume and total head, convert to daily energy, and compare with the trailer’s output in the worst month the water is needed.
Can the trailer work with a diesel generator?
Yes. A hybrid controller runs the pump on solar first and starts the generator only when solar and batteries cannot keep up.
What maintenance does a solar pumping trailer need?
Regular panel cleaning, cable and connector checks after moves, battery and controller inspection, and the pump’s own maintenance schedule.
Have a pumping job to power?
Tell us the daily water volume, head and site location, and our engineers will suggest a trailer and pump arrangement.
Send drawings, load data or questions via the hybrid power enquiry form; the switchboard is +27 10 822 2324 and the inbox is info@uspeglobal.com. Backup generators for hybrid pumping can be found in the USP&E inventory.