Solar pump panel size

[WindriderNM]

I just got 2 circulating pumps from China with the following specifications right now I have a hook to a 12 V power supply to test the system. It is working well and I would like to change to a 12 V solar panel. I noticed in the specifications that the maximum size panel is 15 W. The smallest panel I have is 55 W. I was wondering if this would work or do I need to put a control on it to turn it off when the voltage drops below a set voltage? I am wondering why the maximum panel size is 15 W. Or maybe they mean minimum size.
thanks for the help
Craig



This pump can be powered from any 12V source or directly from a PV Solar Panel.
          * Voltage Range : 6V-24V

         * Nominal Operating Voltage : 12V

         * Maximum Fluid Temperature : 212

         * Maximum Fluid Pressure : 145 psi

      * Can Run With Hot Water (212o F) and at High Pressure (145 psi)

       * Brushless - no Brushes to wear out

         * Extremely Efficient, only 2 Watts starting power   
 
         * Wire Size : Input two-wirelinelength ofabout210mm

         * Operating Noise :  ≤ 45dB

         * Minimum Start-Up Voltage : 6V

         * Maximum PV Panel Output Power : 15 Watts

         * Maximum Head : 3m

         * Maximum Flow Rate : 12L/M

[mab]

maybe they do mean minimum - unless they're worried that a larger panel will fry the motor? but I can't imagine a 12v panel going past 24v (or maybe they're thinking someone might connect up a >15w 24v panel, which would fry the motor).

I suppose you could use a diode to divert any excess to a 12v battery (if you have a 12v battery system)

[GaryGary]

Hi,
I don't see why a 55 watt 12 volt panel would not be OK.
I agree that maybe they really mean minimum 15 watts, which would make sense.

You can run the pump direct off a PV panel and basically use the PV panel instead of a differential controller to run the pump at the right times.
This does not work as well as using a differential controller because 1) the PV panel and solar thermal panel have efficiencies that go in opposite directions with the temperature changes -- so, if its set up right for medium temperature day, then on a cold morning, the PV panel will start the pump early because the PV panel is more efficient in the cold the the thermal panel is less efficient in the cold, and 2) the differential controller knows how hot the water in the tank is and only turns the pump on when the collector water is above the tank temp.  The PV panel does not know the tank temp, so it may turn the pump on to early if the tank is already warm, or too late if the tank is cold.
All that said, the PV panel direct to pump works pretty well.

ArtTec sells a differential controller that is made for use with pumps driven by a PV panel.
http://arttecsolar.com/

Can you give us a link for where you purchased the pump?  Looks like it might be a good choice.

Gary

[WindriderNM]

I bought them on eBay for about $25 each. The ad says they should run for over 30,000 hr.