The nice thing about a solar powered pond is that the pond pump is off during the winter! I only have to design around the spring summer and fall.

First design thought, I will not run the pump at night. I would say I would run it from 9am until 6pm.

Second design thought, AC or DC? An all DC system would be good because of no inverter losses. Even so, inverter losses are only about 5% on average. Because of start-up currents I would have to oversize my inverter to compensate. That means more money for an inverter. I do like the keep it simple approach. One less item to purchase and maintenance. DC system it is.

Third design thought, 12V or 24V. This is a little harder. It really depends on total system wattage. I have been looking at boat bilge pumps. A 2000 gph pump draws 8.4 amps @12Vdc. That is only 100 Watts.  The same size pump at 24Vdc draws 4 amps. That is 96 Watts. This is a small difference of 4 watts but it is worth noting. Now comes the charge controller. I want to use a MPPT type controller. The Sunsaver MPPT controller has a better efficiency @24Vdc. It will do both voltages. So I could start at 12 VDC and upgrade to 24VDC later.

Forth design thought, No controller, No batteries? They sell linear boosters for just this, pumping water. At about $100, this would be cheaper then batteries and a controller. Since the units are sized in amperage instead of voltage, it is better to get the 24VDC pump. All pumps do the same amount of work so the 24V pump has half the Amp rating. P=I x V

What Have I come up with?

  1. Rule 24V bilge pump – $125.
  2. Linear Current Booster PPT 12/24 – 7V – $100
  3. Solar Panel ~120W – $500? (Slightly Over sized) Still looking for a deal. Shipping is what gets you.

So for about $700 I cold have a nice pond setup. For reference, my father in-law has a small pond. He runs his pump 24/7. It adds about $20 to his electric bill each month. Another issue I had not mentioned, I don’t have to or want to run the AC line for the house up to the pond. No trenching or conduit or GFCI outlet or or or… Just a water fall and solar panel.