Submersible Helical Rotor Pumps.
Operate at higher voltages of 45 to 120 volts DC. These pumps require a pump controller or internal electronics to assist in getting the pump started after periods of inactivity. These are very sophisticated pumps but have a high water to power yield. They are most efficient at the 40 foot to 180 foot range. These are sometimes referred to as the Archimedes Screw Pump and are a fairly new arrival on the solar water pumping scene. Examples of this type of pump are the Dankoff ETA pump and some of the Grundfos SQ Flex pumps.

Surface Diaphragm Pumps.
Available in either 12, 24 volts DC or 120 volts AC. These pumps perform best if operated from a 12 or 24 volt battery bank or from grid power. They are good for delivering small quantities of water from a surface source up to about 100 feet in lift. Suction is only about 10 feet so they need to be located close to the surface of the water being pumped. On rare occasions they can be used in an array-direct (with pump controller) but we have found that life expectancy is greatly reduced. Examples are ShurFlo 2088 pumps and RV pressure pumps.

Surface Centrifugal Pumps.
These pumps are less common in the solar water pumping field than they were in previous years and use impeller pumps connected to DC motors of various voltages from 24 to 120 volts DC to move larger volumes of water over relatively low lifts. These pumps require no pump controller since they do not start under load. They have minimal suction capacity. If they are used in pressurizing applications, they require a flooded inlet and a suitable battery bank. An example of this type of pump is the SunPump SC pump and the SunPump SCB Piston Pumps. These pumps are usually operated at 45 volts to 240 volts DC and are excellent for lifting surface water to extreme heights. A DC motor drives a pressure pump similar to that used in a car wash to create enough pressure to push water to heights exceeding 1000 feet. These pumps are built to your specification by our friends at SunPumps.

Floating Centrifugal Pumps.
These are high volume, low wattage pumps but need to be floated on a pond, ditch or cistern. They lack the ability to lift water very high but are good for keeping livestock out of riparian zones where contamination from animals is of growing concern. They operate from 12.5 to 30 volts DC and require no controller. Examples are the Sun Motor M-3 and M-20 pumps.

Pump Jacks.
Once the backbone of the deep well, solar pumping industry these pumps are great for pumping from very deep wells or wells that have too small a diameter to get a submersible pump into. While the hardware to make this pump is relatively expensive there is very little to fail and life expectancy is measured in decades. They can operate from 30 volts DC for very shallow wells to over 200 volts DC if water is very deep. These units require special controllers for starting and running under heavy loads. They operate on the same principle as oil field pumps. An example is SunPumps SJ series pumps.

As you can see from the above list of pump types there are many application factors to take into account when choosing the appropriate pump for any given pumping situation. For this reason, we usually like to talk to the customer before sending out a pumping system to ascertain that the system will perform as desired. We have included a Water Pumping Questionnaire which you can print and fax to us so that we can make sure your system is properly designed. Our Fax Number is 406-363-6046 and we are more than happy to work with you on your pump system design.