A solar-powered water pump uses the sun's energy to pump water and can be an excellent choice in applications where the volume of water to be pumped is relatively small, the hours of operation limited, the sunshine is plentiful, and access to electricity is a challenge. This form of sump pump is frequently used with water features such as birdbaths, fountains, and small ponds. Cisterns and water tanks that only need occasional pumping are also good candidates for a solar-powered water pump.
This type of pump typically operate on 12 volts direct current (DC). A solar panel converts solar energy to DC electricity that energizes the pump, meaning that it will only operate when sunshine is available. As there is no storage battery involved, it is considered to be low-maintenance.
A solar-powered water pump will typically operate four to six hours per day on full sunshine. On overcast or intermittently cloudy days, the pump will operate for less time. DC-powered pumps designed for solar operation are highly efficient and durable, producing roughly twice the output and lasting twice as long as their alternating current (AC) equivalents.
When purchasing a solar panel separately, it is important to ensure that the panel will provide adequate power to the pump. Adding a charge controller to the system will eliminate potential damage. While a standard sump pump can be adapted for use in a solar-powered system through the use of a current inverter, AC-powered pumps are quite inefficient and require a larger solar panel, offsetting their lower cost. DC pumps, on the other hand, typically can not achieve the higher flow rates of their AC counterparts.
Adding a battery system to a solar-powered water pump system allows pumping on demand within the limits of the battery's storage capacity, regardless of available sunshine. Batteries, however, add considerable expense and complexity to the system and can cost more than the rest of the equipment combined. They also reduce the pump's flow rate by reducing the operating current. Batteries must be safely housed against the elements and can be damaged by temperature extremes. If the solar-powered system's continuous operation is critical, then a battery backup is essential.
Many manufacturers and retailers offer complete solar-powered water pumping solutions. These complete systems come with all the components necessary to operate the pump. Many are designed for specific applications, such as birdbaths and fountains, and can help to take the guesswork out of solar-powered water pumping.