Learn more physics!
I want to use solar electric panels to power a pumpjack for our well. I have used a 1/2 hp 12 volt dc motor at another location for the same depth well (70 feet). Here I would like to go directly from the photovoltaic panels to the motor, so I am wondering about variable voltage dc motors. Am also wondering if I could use a lesser horse power. The reason being the expense of solar electric panels.
- John Weber (age 66)
We're not solar power experts here, but.... With a 1/2 horsepower motor pulling up water at 70 feet you should be able to pump about 1/2 gallon per second, less if the motor is not efficient. Now a 1/2 horsepower motor will take about 370 Watts of electrical power. A quick search of the web shows that a 370 Watt solar unit is going to set you back quite a bit of bucks. I presume this spec is at full noon sunlight, less on a cloudy day or at seven in the morning. As far as DC motors go, they usually will run on different voltages but at different speeds. You might consider using a battery powered pump and use the solar panel to keep the batteries charged. I recommend that you consult a competent engineer for advice. Good luck.
(published on 03/25/09)
Follow-up on this answer.