Using a Dankoff Solar Powered Water Pump – Part 3, by Tunnel Rabbit
(Continued from Part 2.) If a 100-watt panel is used, the voltage could be 17.5 to 19 volts at its peak amperage, which is too high for long-term operation. As tested, I use two 100-watt panels, that have one cell covered with duct tape to reduce the voltage at the pump. Voltage is confirmed using a multimeter, and output measured with a one-gallon container, and a tachometer confirms that the pump head is turning at less than 1,725 rpm. Output should be slightly less 2.50 gallons per minute (GPM) if the Dankoff Model #1303 is used, and slightly less than …