System to pump water

I want to come up with an inverter and pump to pump water to irrigate a garden as a casual project. I have a pallet of 315 watt panels and two) four panel ground mount racks to play with.

I really have no plan except using four panels on a rack and pumping water up hill when the sun shines. I don't expect state of the art performance. If you know of an inverter and pump that I could wire to move some water 25 feet uphill at a current demand that the 1200 watts of panels could support it would help me.


I am not sure what voltage I should try and invert/transform to or how. I am looking at string inverter or micro-inverters and considering trying to output 120 VAC to operate the pump from or 12 VDC and find a pump for that?

For simplicity it would be easier to have no battery and just pump off the panels, but also though a car battery to buffer may be better to help a pump start.

Thanks for reading, Ken

kenabcd said:

I am not sure what voltage I should try and invert/transform to or how. I am looking at string inverter or micro-inverters and considering trying to output 120 VAC to operate the pump from or 12 VDC and find a pump for that?

Click to expand...

String and micro inverters are designed for grid tied systems and require grid power to operate, that's not going to work for you.

You're going to want to go with a DC pump and a battery to keep power smooth when clouds roll by or the like and provide the extra oomph to get the motor started. A 60a MPPT controller, a couple of cheap WallyWorld lead acid batteries for a 24v system, and a good sized DC pump with maybe a photo-eye if the controller doesn't support day/night mode sounds about perfect. Cheap, reliable, cold resistant, automated.

The pump selection is beyond my expertise but I'm sure there's a Groundfoss out there that would be perfect, and I'm sure others will pipe in with recommendations.

They make dedicated controllers just for submersible pump operation. Match the watts of panels to the size of the pump, then connect the pump to the controller, and panels to the controller. The controller decides when to start the pump based on the available solar.

If anyone could specify an inverter model # that I could purchase somewhere that I can hook to four 315 watt panels that would produce 12 volts that I can use to maintain a battery that would run a 12 volt pump it would really help me.

A recommendation of a reputable supplier with low cost inverter that is in stock would be great.

I plan to select an inexpensive 12 volt pump and logic to control it once I have the inverter up and running.

Thanks Rednecktek for helping me with the voltage selection.

Just to throw some math at you:

4x 315w = 1260w / 12v = 100a SCC... that's HUGE and EXPENSIVE
4 x 315w = 1260w / 24v = 50a SCC... That's much more reasonable and gives you benefits of higher voltage for longer and thinner wires.