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Project # 2: Solar Pond Fountain
#1
I have started planning my second build and want to confirm my plans before I order parts.

The first project was an off grid solar setup to power an electric fence for farm pasture.

For my next project, I would like to get it up and running without a battery.

For a quick install & setup, I am thinking I can go direct from a panel to charge controller to inverter to intermittent on/off timer to pump (4 amp).

System Power to pump would be off at dusk until I build a battery.  (Yes would still need a small battery as required by charge controller)

At dawn when panel reaches required voltage, the pump would start cycling again (Power cycling recommended to prevent heat buildup in pump).

Question: I want to reuse the same/similar setup I used on my fence which was 100W with 30 amp charge controller.

Since I did not need to deal with any inverter sizing & conversion losses for my first setup, what would be a typical spec for an inverter to direct power the (4 amp 120v pump)?

https://www.generatorjoe.net/html/electricmotor.html

Seems like there are a lot of junk inverters out there that I need to sort through.

https://www.youtube.com/watch?v=D-swPzh6u2Y

tks

RE: Modified sine wave not good for "any" electric motor. When it comes to electric motors, the ratings on the tag are "running" values, not starting values. Generally speaking, an electric motor can consume up to 5x the rated power when starting up. A compressor style motor will most likely get closer to that than one like for a fan.
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#2
You might be better off looking for a DC pump, then you just need this:
Panel > DC "maximizer" circuit > pump.
Simpler, cheaper, more efficient.
The maximiser circuit lets the motor start & gets the best wattage out of the panel.
You could still easily do a timer for the on-off duty cycle if needed.
Running off solar, DIY & electronics fan :-)
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#3
What gph/gpm flow rate do you need?
How high does the water need to be lifted?
later floyd
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#4
Some semi-related ideas you might want to consider:

This year I dug 3 "sandpoint" wells with AC pumps for the Koi/Goldfish pond (130W, always on), front yard irrigation (500W, on-demand), and back yard (500W, on-demand).  The irrigation pumps also feed a Japanese style bamboo drip fountain thingy, so the big pumps turn on once every couple of hours.  The wells are fairly simple to install, provided you have reasonably shallow water table, and soil with no large stones.
 

The clean well water dripping into the pool ensures that it's always filled, and some dirty water and floating debris overflows.  The fish are very happy, as well as the toads that come to sit in the overflow during dry spells.

I didn't particularly like the idea of the big pumps turning on at random times during the night, so I considered putting a 500L reservoir tank on the roof that get filled during the day (auto-stop with a toilet-style float valve), and provide drip water for the fountain.  Though very much possible, decided again that as it would have been more complicated and costly.
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#5
(06-27-2020, 05:08 AM)Redpacket Wrote: You might be better off looking for a DC pump, then you just need this:
Panel > DC "maximizer" circuit > pump.
Simpler, cheaper, more efficient.
The maximiser circuit lets the motor start & gets the best wattage out of the panel.
You could still easily do a timer for the on-off duty cycle if needed.

I second the idea of direct DC pump. It's a chore to build a battery system unless you need it to run at night. It all depends on your flow rate/pressure.

I use a 12V Shurflo pump for irrigation and to fill two 300gallon IBC tanks. Been using it for over 10 years. I started with a 12V 160W panel and built a home made boost circuit. I have since switched over to a 30A CC/CV buck/boost from Aliexpress when I switched to a 24V panel. A motor needs amps to start so during early mornings or cloudy days the voltage might drop but keep the amps high enough to turn the motor.

The pump I use only runs for a couple hours to fill the tank per day. But it is rated for continuous duty and I put a 12v fan on it. Diaphragm pump so it runs dry while it self primes.

https://www.northerntool.com/shop/tools/..._200352048

But if you need more power/flow and want to run direct then you can consider a direct AC 1 or 3-phase inverter like this from mppsolar.
https://www.mppsolar.com/v3/sp-series-3-phase/
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#6
I was targeting a submersible pump with over 1000 g/h that would float just below surface of pond. There are several youtube vids for this type of DIY setup.

I may need to compromise if I go with a 12v pump as I am finding these peak in the 300-500 g/h range.

I can find options for higher capacity but they all have bad reviews.

To get his running quickly, I would go with an AC pump and 1000w inverter (pure vs modified ???), but I am concerned I will spend the money and get something that will fry on first use as in the vid I attached. A good quality inverter could be re-purposed for other off grid applications.
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#7
Is it an options to do multiple pumps instead of one big one?

Starting & running pump motors is going to mean you need a better quality inverter & a battery, charge controllers, etc , etc. Do-able but not cheap.
Running off solar, DIY & electronics fan :-)
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#8
I have a 2.5 gpm flowjet gear pump (That will not self prime) so have a general idea of what the 3.5 gpm pump from Northern would provide.

I don't think 2 (3.5) gpm pump will work especially when each one is $200.

This one may be an option to consider given (23 gpm) & (12 A)

https://www.northerntool.com/shop/tools/..._200779486

Northern also has this one that is 5.5 gpm but is 15 amps. I would consider to run (2) pumps, but I imagine each would need a dedicated solar panel

https://www.northerntool.com/shop/tools/..._200352044
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