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Last Updated on: Tuesday, October 14, 2014 06:34 AM

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More  Solar Circuits, Control, Motor Controls


A Discover Circuits visitor had a problem.  He needed a simple on/off controller for his solar powered water pump.  His system used two 12v 50 watt solar panels wired in series.  The power from the solar panels drove a submerged water pump.  However, during overcast skies the pump motor did not operate properly due to the lack of power from the panel.  He wanted a circuit which would turn off power to the motor during low sun conditions.  The circuit below performs this function.  A small 0.1 x 0.1 photodiode monitors the sunlight intensity.  The current from the diode is proportional to sunlight intensity.  An adjustable load resistor across the diode converts the current into a voltage and feeds the to a voltage comparator circuit.  The output of the comparator drives a small n-channel MOSFET, which in turn drives a high current p-channel MOSFET, controlling power to the pump motor.  When the sunlight is less than one fourth of full intensity, power to the motor is turned off.


Solar Powered Water Pump


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solar-powered water pump control design by Dave Johnson

More  Solar Circuits, Control, Motor Controls

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