First there were skins filled with water that had to be carried from a source of water to the point of usage. Later, after animals were domesticated, they were used to carry the water and operate rudimentary pumps to accomplish the same thing. Over thousands of years, the nature of pumping water has changed many times and made gigantic leaps in technology. Now we have a device that uses the awesome power of the sun to pump water in places where the power companies seldom venture. Many farmers and ranchers are finding out that by using solar powered pumps they can now graze their cattle on pastures that were previously unproductive due to the lack of livestock water. They can now turn that remote property into income because they are able to graze and water the livestock in close proximity to each other, not worrying about the stock walking off their weight gains to access drinking water. Villagers in dusty African towns can now have clean drinking water and water for cleaning thanks to solar water pumps. Wells in the desert are especially good sites for solar pumps since the brighter the sun, the more water they produce. Actually, some small scale irrigation is being practiced using the power of the sun to drive pumps to drip irrigate plants (see next page). This ability to produce water with sunshine in desert villages has freed many laborers, traditionally women and children, from the time consuming task of hauling water from distant springs. This additional free time allows families to spend more time caring for gardens and livestock, preparing nutritional food and leading healthier lives. Yet, many people have never heard of solar water pumping and are amazed to find out that the technology has been around for three decades. In the early days of solar pumping, simple DC water pumps like those found in motor homes and campers were attached to batteries and a solar module or two was attached to the batteries to replace the current drawn by the pump. We actually still use this technique on a limited scale today but solar pump technology has come a long way since those early days. We now have several excellent solar submersibles, solar pumps for really deep applications and high quality solar surface pumps for extremely high lifts; all designed specifically to run off of the sun. All of this is accomplished without the use of batteries.

While batteries may seem like a good idea, they have a number of disadvantages in pumping systems. First, batteries reduce the efficiency of the overall system. The solar modules’ operating voltage is dictated by the battery bank and is reduced substantially from levels which are achieved by operating a pump solar direct. Batteries also require additional under and over-charge protection circuitry which adds to the cost and complexity of a given system. For these reasons, and the increased maintenance involved, only about 5% of solar pumping systems employ a battery bank and we suggest you avoid them unless they are part of your existing residential solar system.