How big a solar panel should I use for a 5w water pump

Let's say you want to pump water from a depth of 50 feet at a rate of 5 GPM using a 12V pump that is 70% efficient. The region receives an average of 6 hours of sunlight per day, and you want to use a 12V solar panel and battery. Using the Solar Water Pump Sizing Calculator, the minimum solar panel wattage required is calculated as follows:

For water pumps, monocrystalline and polycrystalline panels are generally recommended due to their higher efficiency and reliability. The power requirement of your water pump is one of the most critical factors in determining the type of solar panel you need. The power requirement is usually measured in watts (W) and depends on factors such as:

Solar panels, however, provide power in watts (or kilowatts). Thus, the first task in sizing solar panels for your well pump is to convert the pump's horsepower into a comparable unit, typically watts or kilowatts. Let's use a 3hp motor as an example to explain the process. Using the conversion factor of 0.746, the calculation becomes:

3.81 kW 250 watts = 18 panels Based on our calculations and real-world conditions, you would need approximately 18 solar panels, each rated at 300 watts, to sufficiently power your well pump while accounting for various efficiency losses. Understanding the energy needs of your water pump is critical.

As a rule of thumb, approximately five solar panels are often needed to run a 1 hp solar pump. Following this comprehensive sizing guide, you can accurately determine the solar array size needed to match your well pump's demands.

The Solar Water Pump Sizing Calculator is an essential tool for individuals who rely on solar power to pump water. By providing the required input data, users can accurately calculate the minimum solar panel wattage and battery capacity required to meet their water pumping needs.