Are DC pumps more efficient?

As a practical, upfront answer, Yes – DC pumps are more efficient than running on solar power. That’s because the DC power travels straight through a charge controller down to a DC pump, very little inefficiencies as the type of power stays the same throughout. Compare that to AC pumps that run on solar with the help of an inverter, DC power must be chopped up into AC three phase 220V power, which results in a bit more inefficiency. A DC pump uses less panels and is overall less expensive than a converted AC pump on solar. For example, a 1/2 HP solar water DC pump might only use two or four 100W solar panels(200-400W) whereas the same 1/2 HP AC pump must use eight 100W panels(800W).

DC pumps are great for low to mid head applications, like wells up to 300 feet deep, and lower flow applications, up to 15 gallons per minute. Plus, adding on batteries for nighttime use is easy for systems like the RPS 200, 400, 800, and 400N.

When you need a solar water pump for a deeper well (up to 1,100 feet), higher volume flow applications (up to 400 gallons per minute) or just want built in automatic switching between 220V back up power and solar power, then an AC pump using solar is the best option. RPS only uses three phase AC pumps, as that’s the most efficient way to power a water pump using solar. A three-phase submersible water pump transmits 3X the power of a single-phase water pump while only using 1.5 times the amount of conducting material. Meaning, you won’t spend more money on wire for a three phase pump with better overall design, less noise and superior output.