Quick Answer
To power a well pump, you'll need a solar array that can produce between 1.5 and 3 kilowatts (kW) of electricity, depending on factors like pump size, flow rate, and well depth.
Determining Pump Requirements
To size a solar array correctly, you must first determine the required power for your well pump. This typically involves selecting a pump based on the well’s characteristics. A typical well pump for a residential well might require 1-3 horsepower (hp) to move 5-20 gallons per minute (gpm) of water at 50-100 feet of static head.
Sizing the Solar Array
For a 1-3 hp pump, you’ll need a solar array that can produce between 1.5 and 3 kW of electricity, considering a 10-20% efficiency loss due to inverter efficiency and shading. For example, a 2 kW solar array would require 6-8 panels, each producing around 250-300 watts. When selecting a solar panel, look for high-efficiency panels with a rating of 22% or higher.
Additional Considerations
Keep in mind that your solar array’s power output will fluctuate with changing weather conditions. A battery bank can help stabilize the power supply, but this adds complexity and cost. When sizing a battery bank, consider the pump’s daily energy requirements and the solar array’s daily energy production to ensure the system can meet the pump’s needs during periods of low sunlight. It’s also essential to select a well pump that’s compatible with solar power and has a suitable voltage rating for your system.
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