In 2009, we bought an acre of land in Homestead, Florida, 35 minutes south of Miami. Since the parcel had no electricity and no structure to accommodate a large PV array and the related inverters and water pump for a full-scale sprinkler system, I settled for a PV-powered drip irrigation system.
I wanted it to be as simple as possible with the least demand for equipment. The solution was to use a 275-gallon plastic tank ($60 used), and a 2-inch electric valve ($100) to release the water controlled by a timer ($12). Electricity is supplied by a Unisolar PV136 module ($125). The water pump is a 4-inch, 24 V, 1.6-gallon-per-minute well pump ($145) at the bottom of the shallow well. The battery storage is two marine batteries ($58 each). The water tank has a 2-inch manual valve that goes to the electric valve control and then to 2-inch PVC main pipes, which branch into 3/4-inch flexible plastic tubes.
I have about 82 trees. Each tree is fed by a 1/4-inch drip tube coming from the 3/4-inch secondary tubes. All this is accomplished by gravity, and in 10 minutes each tree gets about 1.5 gallons of water—more than enough. It then takes the pump 11/2 hours to replenish the tank.
The battery bank never drops below 85%, and it gets recharged 100% before noon. The single module provides more than enough energy for the task.
Chunin Martinez • Miami, Florida