This is a system of small pump modules that work together as a powerful array.  Each is independently powered by an onboard solar charged battery supply.  The lack of central power means short wire runs, and no resistance in the electrical lines.  The electric motor is driven by a capacitor which pulses only when it is fully charged by the photovoltaic cell or battery.  Thus the pump operates in powerful quick bursts at regular intervals.  Each pump module has its own intelligent microcontroller and various sensors that let it work in efficient harmony with the other pumps in the array.  The bottom of every pump module is a basin that holds about a quarter liter capacity of water.

The biggest efficiency hurdle in pumping water up over 5 meters, is the back pressure of the water column in the pipeline.  This can be avoided by stepping the rise in more manageable distances.   And so the modular pump array is an effective strategy for boosting efficiency and getting the job done economically.  The individual pumps need not be powerful.  At each cycle, they only need to push a small amount of water a short distance.  The cycle rate is determined by the amount of energy produced by the photovoltaic cells. Typically, the capacitor will take about 8 seconds to charge, during which time the electric motor can rest before another sprint.  A module will intelligently delay pumping if the module below it is falling behind.  There is a water level sensor in each basin that tells the microcontroller when to wait, and when to resume.  The pause is only a matter of seconds, but the array operates most efficiently when synchronized.  The pump modules fire one after another in a ripple effect.  The pumps are connected only by a length of hose, but that is enough for effective communication between modules.  The result is a reverse cascade, bringing water quickly and steadily up the staircase.

The target retail price for the individual modules is under $25 USD.  This is possible because no exotic parts are being used.  For example, the arduino nano microcontroller, 1W radio shack solar cell, and 5V electric hobby motor, all wholesale for under $5.  Other parts are standard pipe fittings.  

Optimally, it requires 20 modules to raise water 6 meters at an average rate of 85 liters per hour.  With a $1500 USD budget, that will buy a farmer 3 arrays worth of modules, with a total pumping capacity of 255 LPH.  60 modules will fit easily in a large suitcase if partially disassembled.  Or alternatively they can be stacked on a cart.  Each module weighs less than a kilogram.  Setup is quick and easy requiring no tools.  The modules clamp to standard galvanized steel pipe using hand tightened knobs.

The microcontrollers keep a service record and daily performance record of themselves, which should be downloaded nightly and stored remotely.  That way you can fine tune the location and placement of modules for ever better results.  You'll also be alerted about modules in need of adjustment or servicing.  System software can be continually upgraded with the onboard microUSB port.  Unforeseen features or customizations for specialty applications may arise at a later date.  the microcontrollers also double as a charge controller for the AA NiMH batteries.  When there is momentary shade, the batteries can fill in for the solar cells to maintain optimal timing without hesitation.

By pumping smart, we achieve our target goals with only 60 watts of free clean energy.