Solar Powered Water Pumps

Solar powered water pumps are designed to use DC power (Direct Current) supplied by solar electric panels. The motor in these pumps is very reliable and is designed to continue operating even during low light conditions without stalling or overheating so that there is a constant output or water. Operating under these conditions means that the pump will continue to operate under low power conditions but still deliver water at a reduced rate. To enable them to operate under these varying conditions, most use a positive displacement design rather than a centrifugal design which requires higher operating speeds to work efficiently.

Solar water pumps are great for backyard projects such as garden ponds and fountains and any other home project where electricity is not easily available. These pumps are very reliable, require little maintenance and last for many years.

The difference between a positive displacement pump and a centrifugal pump

A positive displacement pump seals water in cavities so that even when the pump speed slows during periods of low power supply, it will continue to move the water in the desired direction but at a reduced rate. Displacement pumps include piston, vane and diaphragm designs. Centrifugal pumps use impellers which draw the water in through the center of the impeller and then forces the water out of the impeller to the pump discharge using centrifugal force. If these pumps don’t operate above a minimum speed the water will begin flowing back through the pump and water flow will stop.

There are two types of solar water pumps

There are two general types of solar powered water pumps, surface pumps and submersible pumps and both are available with small and very large flow rates. Submersible pumps are installed below the water surface and are used in wells, fountains and ponds. Surface pumps are for above ground use and must be protected from the weather. Solar powered water pumps are capable of pumping less than .5 gallons per minute (2 liters) to over 100 gallons (375 liters) per minute. Most deep wells use submersible pumps. Surface water pumps can be used for depths less than 30 feet (9 meters).

Ensuring there is enough water

Many applications like a backyard fountain and pond doesn’t require an uninterrupted, minimum supply of water at all times because the flow of water is not really that critical, but for farming and drinking water a minimum supply may be very important. There are some measures that can be used to ensure that supplies are constant and uninterrupted.

Solar trackers are often used with these systems to control the solar panels tilt. A solar tracker is a device that moves the solar panel keeping it at the most beneficial angle to the sun and ensures that the water pump will be provided with the maximum possible power all day. Another method of ensuring adequate water supply is to use storage tanks that utilize floats to control the pumps. These floats turn on the solar pump when the water level in the tank is low and turn them off when the water level is high. Battery back up is even available for these systems to ensure constant operation.