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That pesky well pump

 
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I think we could get by quite well (no pun intended), with a small solar system... except for starting our well pump.

So I've thought about various mixed solutions, a small solar system plus:

- a diesel generator (so I could share diesel with my truck and tractor)
- a propane generator (longer term fuel storage)

And so on.

But maybe there are alternate ways to get water out of the well (about 180 feet deep)? I've seen the system that you can add to your existing well system to allow hand pumping..

Maybe a smaller, easier to power well pump?

Maybe 4 people riding bicycles attached to generators to run the pump for a few minutes a day/

I know, all sorts of crazy ideas, but my mind has been spinning on this for a while now..

Thoughts?
 
gardener
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The folks at Living Energy Farm swear by their Grundfos SQ Flex well pump. It looks like those go for about $2,500. But they can take DC or AC, from 30 VDC to 300 VDC. The price isn't friendly, but well pumps wear out over time. Maybe you change everything else over to off-grid, and have a plan to change the well when it is time to change the pump.
 
steward
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Quick question, do you already had a well pump and are looking to add solar?

If so maybe the forum needs more info about the well pump you have.

Or do you need a well pump and looking for ways to power it?

In the meanwhile here are some threads that might help?

https://permies.com/t/171633/Solar-pump

https://permies.com/t/63316/Submersible-solar-pumps

https://permies.com/t/15715/experience-solar-powered-pumps

There is also a PEP Badge Bit [BB] for that so you can see how others have done there and get a BB for installing yours:

https://permies.com/wiki/112936/pep-electricity/Set-solar-water-pump-PEP

 
Bert Bates
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Anne Miller wrote:Quick question, do you already had a well pump and are looking to add solar?

If so maybe the forum needs more info about the well pump you have.

Or do you need a well pump and looking for ways to power it?



I already have a traditional well pump, I'm guessing it's 3/4 HP.
 
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It is not so easy to add a second siphon if you intend to include a hand pump.  Larger AC well-pumps almost always have what's called "torque arrestors" incrementally positioned down the well.  They are rubber bulbs that wrap around the well-pipe, to cause friction against the sides of the well-casing, so that the pipe doesn't spin in the opposite direction the pump is spinning.  That means you can't just slip a second pipe down the well.

That being said, solar alone can do it, especially if your pump is only 3/4hp.  Looking at my pump chart, a 3/4hp pump at 240VAC needs 8.4A to run, and 31.4A to start.  Starting is the big deal.  The starting current, called the "inrush" is typically 4-5X higher than what it takes to run the pump.  For my 1hp Grunfos, the running amps is 9.5A and starting is 38A.  My Schneider XW+ 6848 inverter handles that starting surge just fine.  

You might not need an inverter as large as my 6848.  Schneider does though make a smaller 48V model, the Conext SW4048, which is documented to surge to 7000W for 5 seconds, with a peak current rating of 41A.  Since your pump only draws 31A at startup, I'd think it would work.  The 4048 is nice in that it is a native 120/240VAC inverter, and also has a built-in generator charging circuit.  That means you just plug the inverter into a generator, and it accepts generator power to charge the batteries in rainy/snowy weather.

A good rule of thumb I recommend is to have 2X the watts of panels for the watts of your single biggest load.  If your pump draws 8.4A X 240V = 2016W, I'd recommend having about 4000W of solar.  High-voltage residential panels in the 250W range are running 40-50$ these days, so you are likely to get the 16 panels needed for ~800$.  Look at some of my other posts.  I built a rotating array frame that can hold six 250W panels.  If you made two of those carrying 1500W each, when rotated towards the sun, you most certainly will make enough power to run your pump, as long as the panels are oriented towards the sun.  When they are, my 2X rule only needs to be a 1.5X rule.

With 3000W of solar, charging at 50+V, you'll need a charge controller that can handle at least 60A.  Epever makes a Tracer6415AN that is running ~250$ I think.

Be careful though evaluating cheaper imported inverters.  A lot of them will claim they can surge to 200% their rated wattage.  What they don't tell you is that their inverters can only surge that high for 8-16 milliseconds (not seconds).  You need a quality low-frequency transformer-based inverter that can handle a well-pump with a starting surge in the 500-1000 millisecond range.  

So, a Conext 4048 inverter, 6415AN controller, 16 250W panels, and eight Trojan L-16 batteries, and you will have a working system that will start your pump.  Throw in some extra for breakers, copper wire, and sweat.
 
pollinator
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The important parts for well pumping with an inverter are
1) make sure your pump has a soft start function such as the grundfos listed above.
2) for decades of service stick to the more traditional transformer based inverters ( outback, magnum, Schneider) rather than the less expensive high frequency units currently taking over.
You could run the pump on a dedicated line from a generator and feed a surface tank one every now and then and use a smaller solar driven pump to provide pressure for the house.
Finally have you checked what height the water is at in your well? I have a 280 ft well but static pressure is 40 ft. If I wanted to I could hang a secondary pump at say 60 ft and access 20 ft of water at very low power.
I find the hand pump options very expensive though. A client of mine managed to buy a generator and install a backup power panel for less money than what they wanted for one of the cast iron deep well hamp pumps...

Some things to consider.
Cheers,    David
 
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Another option is to pump with an air compressor, any size *can* work though one that is too small will have a low flow rate. The size of the compressor also needs to be fairly balanced with the size of the water line. Mine is a 110v 3/4 hp motor turning a twin cylinder air compressor (rated for 5hp) with a belt. Main downside is that the air comes back up with the water which is fine for filling my cistern but would be weird if it was plumbed directly to a house. Big upside is no moving parts or electric down the well, just a waterline and an airline.

I could also build a windmill to drive the compressor but haven't gotten around to it yet. My water line is 3/4" and I get around 4 to 5 gpm. I really like having all the expensive bits above ground, though I can pull the 250' of plumbing out of the well by myself if I need to. I also like that if things got really weird I could fill an air tank with a bike pump to get at least a few gallons per day. I installed the same setup for my neighbors, they are using a $99 pancake compressor.
 
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Hi there Buster,
Any chance you can elaborate on your air compressor setup?  What about freezing temperatures etc?  I could keep a compressor in my basement perhaps with a water line running through the wall, 4' below grade to our well 15' away.  The water level is at about 30' down.  Very interesting idea.  Thanks for it.  Otherwise, I'm slowly working on a gravity feed system (spring running to a 1500 gal cistern piped to the house) and have a Bison hand pump as of now but would love to get running water to the house sooner than later.

 
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