To choose a 5 hp solar submersible pump, work out your daily water need and total head first. Then size the solar array and controller to the pump, not the other way round.
A 5 hp motor is about 3.7 kW. In a solar system the array is usually rated somewhat above the motor, because panels rarely deliver their rated power in real sun.
What are the parts of a solar pump system?
A system has four main parts: the solar panels, a controller or drive, the pump with its motor, and the mounting and cabling. Some pumps use a DC motor. Others use an AC motor driven by a solar pump inverter, which tracks the panel's maximum power point.
Our article on solar pumps made in Gujarat covers what is available. A variable frequency drive is the part that controls an AC motor. See what a VFD is and whether it can be supplied with the pump.
How do you size the pump?
Use the numbers that decide the pump:
- Daily water need in cubic metres, based on crop or use.
- Total dynamic head: vertical lift, pipe friction and delivery pressure.
- Borewell diameter and depth, which limit the pump size.
- Available sun hours at the site and the seasonal low.
How do you match the array and the controller?
The controller has a maximum input voltage. Panels wired in series add their voltages, and open-circuit voltage rises in cold weather. If the string voltage exceeds the controller's limit, the controller can be damaged. Ask the maker for the array layout, the number of panels per string and the voltage window it expects.
The array power should be at least the motor rating, and makers commonly recommend more. Ask for their recommended array size for your head and flow, and compare it against the pump curve at the reduced power you will see on a cloudy day.
International standard IEC 62253 covers design qualification and performance measurement of photovoltaic pumping systems. Ask whether the maker tests to it, and ask for the test report.
What else should you check?
Ask about dry-run protection, which stops the pump when the water level drops. Ask about the panel warranty, the controller's enclosure rating and cable sizing. Long cable runs lose voltage.
Confirm whether the quote covers the panels, structure and cable, or only the pump and controller. Many comparison problems come from different scopes. Our article on what decides the price of a solar pump system explains the cost pieces.
Import rules for solar equipment differ by country, so check with your importer.
Plan the site too. Panels need a clear south or north facing slope in the right hemisphere, free from shade for most of the day, and a structure rated for the local wind load. A shaded corner of one panel can cut the output of a whole string, so ask the maker how the strings are wired and how bypass diodes are used. Dust also reduces output, so allow for cleaning.
Next step
We shortlist solar pump makers, test the pump and controller together and inspect the full set before loading. Book a free sourcing review with your head, flow and site.