Remote Living > Water

Solar Powered Pond Aerator

(1/4) > >>

OperaHouse:
I've been following some posts on pond aeration and thinking people are trying to turn this into a monstrous costly problem. Found a video from Missouri Wind and Solar (not a big fan) and they demonstrated a 100W panel, $4 ebay buck converter and a 400W inverter. running an air pump.  They further went on to show how a cloud passing over would send the inverter into low voltage shut off.  This can not be recovered from without turning the inverter off, rendering this useless as a finished design.  Then they went on to say they added a relay and the whole system worked flawlessly.  They would give information in the next video. In the second video this had turned into a product you had to buy.

I would like nothing better than to turn this into a microprocessor project.   I couldn't get that "relay" out of my mind and if they are smarter than me, it is time to pack it in. Here is my low tech solution.

1. Use a 280W 30ish volt grid tie panel because it is cheap and their pump was a little smaller than most people use.

2. Connect that to a 24V relay with a resistor in series that prevents the relay from closing until about 35V is present.  Relays have a wide hysteresis and the voltage has to drop to about half before it drops out.   The solar panel connects to the moveable contact and the buck converter to the normally open.  The normally closed connects to a load resistor that would simulate some of the load of the motor.

3. When sufficient power is generated by the panel to run the motor, the relay pulls in and powers the buck converter which in turn powers the inverter.  A 10 or more amp buck converter would be sufficient that can operate up to at least 40V on the input.  These shouldn't cost more than $20.

4. That buck powers the 12V 400W inverter.  I would probably add a couple 1,000uF electrolytics to handle the ripple current. Those buck converters have just enough cap to keep them stable and cheap.

So, when a cloud comes and before it goes into low voltage shut down, the relay will remove power to the inverter. Some playing around with part values, but it should work.  Sounds fun and almost makes me want to dig a pond.

Mary B:
Why not find a 12 volt air pump and power it directly from the solar panels?

SparWeb:
Is there such a thing as a DC pond aerator pump?  (No I couldn't find any with a quick search myself)

The resistor dropping 10V on your relay coil will be dissipating a few watts all the time, and the buck converter will also be wasting a bit of power, but probably not a lot, in the grand scheme of things.

I have several neighbours with ponds that they aerate over the winter to keep from freezing through, stocked with koi or other decorative fish.  They'd appreciate having something more reliable than the klunky windmills or noisy pumps on extension cords.  They don't think of RE solutions (how come nobody does, even after decades of RE ideas in the news?) but this sounds practical enough.

You'll need a weatherproof enclosure, for the buck converter, inverter and the cable connections.

dnix71:
https://www.walmart.com/ip/Solar-Powered-Fountain-Pump-7V-Energy-Saving-Submersible-Solar-Water-Pumps-For-Garden-Pond/148185003

There are lots of self contained solar powered submersible pond pumps out there.

OperaHouse:
People use everything including automotive smog pumps. The favorite seems to be these aerator pumps that are designed for septic systems.  They run for years without maintenance and come in a weatherproof case. These ponds can be rather large and may require multiple pumps.  I encourage any solution that doesn't use a battery.  I'm going into production with a board for greenhouse and pond applications acting as a linear current booster.  In searching around I mainly found battery solution till you get into larger three phase pumps. Thumbs up to those, but those are a big solution.  This Missouri solution seemed practical and couldn't find any other place that explained the method.  Search septic aerator pump like 80-hp for examples.

Early on I experienced inverter shutdown with my refrigerator program. I learned you have to a timed shutoff so in the event of a fault the inverter will reset.  The above system would work as well if it had a timer that just shut it off for 10 seconds every fifteen minutes.  Those timers are available.

I see it as an open ended idea.  The question comes up now and then if an inverter can be used with a solar panel without a battery and DC operating equipment is not available.

The load resistor doesn't have to be that big.  Once you get way above the panels voltage power point the power drops off rather quickly with little current.

Navigation

[0] Message Index

[#] Next page