DC pump directly to PV Panel?

Paul,

The current Laing D5 series is okay for solar-direct operation. Interestingly, I see this warning in a PDF about the "ecocirc" pumps, including D series:

"In order to ensure full service life of the D Series pump, it is important to provide a stable and non-degrading power source at the required voltage. Operating the pump out of the specified voltage range may reduce the life of the motor and will void the warranty."

The date of that PDF is 05/06. Then, in a more recent PDF from them about the "ecocirc" pumps, I see the voltage range described in a spec table as 12-24VDC, and further, that direct-connect is indeed part of their design intention. Max. power consumption of this pump line is 22W. I would say that as long as your solar module is rated as 12V nominal (meaning operating voltage, under full sunlight, of about 17VDC), you should be fine.

Please check out the PDF on their site:

http://www.lainginc.com/

Use navbar on left side of their site to link to "Downloads", then find the appropriate PDF link, which I take to be "Ecocirc D5 Solar information", linked here:

http://www.lainginc.com/pdf/LTID5solar.pdf

Cheers,

Ben

we have had good luck with the laing running pv direct as a method to control pressurized systems pumping.

tom is right a battery will be more stable voltage, but then will either require a timer or 12vdc diff temp control, where pv to pump requires nothing else with a minimal sacrifice in performance in the name of simplicity.

tom, do you use a 12vc diff temp controller in those cases?  i have seen one in home power, but i dont think we carry it yet.

cheers,

james