Head
The vertical height (in meters) that a pump can push water. Total head includes well depth, drawdown, pipe friction and delivery height. See the TDH guide for the full calculation.
GuidesSolar Pump Glossary
Solar Water Pump Glossary: 15 Key Terms Explained
Plain-language definitions of the terms you'll meet when buying a solar water pump. Each term links to the guide where it's explained in full.
Back to guidesTotal Dynamic Head (TDH)
The complete vertical distance a pump must overcome, including static water level, drawdown, pipe friction, horizontal pipe loss and delivery height. The single most important number for pump sizing.
GuidesFlow Rate
The volume of water a pump delivers per hour, measured in m³/h or liters per hour. Your required flow = daily water need ÷ sun hours.
GuidesMPPT (Maximum Power Point Tracking)
A controller technology that continuously adjusts the electrical operating point of the solar array to extract maximum power under changing sunlight conditions.
Best Efficiency Point (BEP)
The point on a pump performance curve where the pump operates most efficiently — delivering the most water per unit of energy. Operating at or near the BEP maximizes pump life.
GuidesStatic Water Level
The distance from the ground surface to the water surface in a well when the pump is not running. Found in the driller's report or measured with a weighted rope.
Drawdown
The drop in water level when the pump operates — the difference between the static level and the pumping level. Varies by aquifer, typically 15-20% of static level.
GuidesShut-off Head
The maximum pressure a pump can produce when no water is flowing (zero flow). This is the "Max Head" number on the spec sheet — the extreme top-left of the H-Q curve.
GuidesCentrifugal Pump
A pump that moves water using a rotating impeller that throws water outward by centrifugal force. The most common pump type for solar water pumping.
Impeller
The rotating component inside a pump that imparts energy to the water. Available in plastic (economical, for clean water) or stainless steel (durable, for sandy/abrasive water).
Submersible Pump
A pump designed to operate fully submerged in water, pushing water up from below. Required for wells and boreholes deeper than ~8 meters.
GuidesSurface Pump
A pump mounted above ground that pulls water up by suction. Limited to suction depths of ~7-8 meters due to atmospheric pressure.
GuidesSolar Panel VOC
Open Circuit Voltage — the maximum voltage a solar panel produces with no load. Your panel string's total VOC must stay below the controller's rated limit.
GuidesCheck Valve
A one-way valve installed above the pump that prevents water from flowing back down the pipe when the pump stops. Prevents water hammer and pump cycling.
Drip Irrigation
A watering method delivering water directly to plant roots through low-pressure emitters. Uses 40-60% less water than sprinkler or flood irrigation — the best match for solar pumps.
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