A real hum dinger, I need a slow pump

Deveak

Solar Enthusiast
I keep looking and I can't find a solution. I have low yield water well thats about 200-225 ft down a valley. I currently run a generator and pump water uphill.
I can't seem to get anything down the well, it necks down to a 4 inch pipe and its crowded so I can't figure out the static. Through acoustic testing I guestimate it somewhere around 50-75 ft. So a grand total of 300 ft of possible head pressure or 400 ft if the water level drops. I can only get about 200-250 gallons of water out of it a day the current way I am doing it. The current well pump is a beast but makes my lights flicked and the generator struggle. I don't like it when my magnum 4000 watt inverter kicks in. It can run it but I feel like it might damage it. Runs about 18 amps at 230 volts or about 4200 watts. I no longer use it to pressurize the house, just fill a tank. I could throw money at it, several thousand dollars for a expensive American pump or 1400-2000 dollars for a chinese pump like RPS sells. So far RPS is the cheapest branded option. Its made in China though and they brag about being made right beside John Deere equipment like that gives it credibility. I don't want to pay top dollar for a Chinese pump. Anyone have experience with a cheaper slow pump? My pumping requires are minimal. Even a 1/2 GPM would do it.
I've seen a few pumps on Amazon that come close to maybe working or reliable. Pumping with Solar/PWS etc. Runs around 500 dollars.
On the AC side of things, slow pumping seems non existent.
Its been the greatest weakness of my property. I have chickens and pigs and they get thirsty in the summer. Rainwater collection helps but I have times where things get a bit dry.
 

snoobler

Solar Honey Badger
You have what amounts to a deep well. Any idea that there is an easy, cheap pumping solution is misplaced.

If you need 400 ft raise, and you get a pump capable of 400 ft head, you get 0 flow. The pump has just enough power to raise the water and hold it there. It's too heavy to make it flow out of the pipe.

Surplus head determines pumping speed. The power required to move water up 400 ft is huge as you've discovered. There's no getting around that.

You need a pump capable of > 400 ft head in order to get any flow at all. There is no such thing as "slow pumping" in the way you're thinking, i.e., a way to move water up a column more slowly to use less power. You can't reduce the power below the point needed to move a big column of water up 400'.

You need to balance gpm with power. If you have to run a generator for 4 hours to get 1/2gpm flow vs. running it 2 hours to get 3gpm flow, which makes more sense?

Other considerations:
Linear run. In addition to a rise, the linear component of the run matters as there are friction losses.
Pipe size. Pipe diameter affects friction losses. Easier to pump through a big pipe vs. a small pipe.
Well performance. Your well has a gpm limit. Do you know what it is?

Overall, it sounds like your system has some severe efficiency issues. For comparison, my neighbor has a 700' deep well with a Grundfos 3hp pump. It runs 12A @ 230VAC (2760W), and he gets several gpm. He keeps 2000 gallons of cisterns full running 2-3 hours per day, 2-3 days per week. No livestock or agriculture, but they have a sizable decorative pond that increases their water usage.
 

Deveak

Solar Enthusiast
I might be measuring wrong, I get around 9 amps per leg. Is that cumulative or total? If I am wrong it’s a 2000ish watts pump so 2 hp? I want to say 9.3 amps per leg at 230 volts. The recharge rate is low, it’s why I wanted a solar well pump at a lower rate.
I usually only have time to pump water once a day, so I don’t get as much as I could.

I might just build a small pump house, insulate it and put a water tank in it. I can use the existing wires to run a smaller pump that will pump uphill and a small and cheap DC well pump to pump from the well to the tank. It would add complexity with float switches but I can't think of another way around it.
 
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snoobler

Solar Honey Badger
I might be measuring wrong, I get around 9 amps per leg. Is that cumulative or total? If I am wrong it’s a 2000ish watts pump so 2 hp? I want to say 9.3 amps per leg at 230 volts.

Only 9.3A. 230VAC only uses the neutral if there's an imbalance, so 9.3 * 230VAC = 2139W, which makes a lot more sense for a 2-2.5hp pump. I would expect a surge of around 10,000W.

The recharge rate is low, it’s why I wanted a solar well pump at a lower rate.
I usually only have time to pump water once a day, so I don’t get as much as I could.

This is a flawed approach. As I mentioned, the vast majority of the power required to pump is consumed by lifting the water and overcoming the friction in the pipe.

There is a minimum amount of power required to get ANY water at all. Let's say it's 2000W. In other words, if you don't supply at least 2000W, you won't get any water. The power above 2000W is what determines gpm. Do you want to pump at a trickle at 2100W for hours, or do you want to pump a firehose for 15 minutes at 3000W?

The numbers are illustrative of scale, not specific to your situation, but the concept applies.

I might just build a small pump house, insulate it and put a water tank in it. I can use the existing wires to run a smaller pump that will pump uphill and a small and cheap DC well pump to pump from the well to the tank. It would add complexity with float switches but I can't think of another way around it.

That may work, but consider that you still have the same total power requirements, though the above allows you to split it up. Your scenario changes the example to only need 500W to draw the water from the well, but you still need 1500W to push it up the hill and through the pipe. This would enable your "slow pumping" scenario, at least to the pump house tank (and I'd make it a BIG one).

IMHO, you should establish your well's actual yield and optimize your pumping system around it.
 

Deveak

Solar Enthusiast
Only 9.3A. 230VAC only uses the neutral if there's an imbalance, so 9.3 * 230VAC = 2139W, which makes a lot more sense for a 2-2.5hp pump. I would expect a surge of around 10,000W.



This is a flawed approach. As I mentioned, the vast majority of the power required to pump is consumed by lifting the water and overcoming the friction in the pipe.

There is a minimum amount of power required to get ANY water at all. Let's say it's 2000W. In other words, if you don't supply at least 2000W, you won't get any water. The power above 2000W is what determines gpm. Do you want to pump at a trickle at 2100W for hours, or do you want to pump a firehose for 15 minutes at 3000W?

The numbers are illustrative of scale, not specific to your situation, but the concept applies.



That may work, but consider that you still have the same total power requirements, though the above allows you to split it up. Your scenario changes the example to only need 500W to draw the water from the well, but you still need 1500W to push it up the hill and through the pipe. This would enable your "slow pumping" scenario, at least to the pump house tank (and I'd make it a BIG one).

IMHO, you should establish your well's actual yield and optimize your pumping system around it.
That doesn't sound right. My current well pump is 12 GPM and about 2100 watts. The first problem is my static well level drops as I over pump the well at a high rate. So the amps go up (a bit) and my rate drops. At best rate thats good at 3 watts per gallon but only in a perfect world.
I would need to run it in really short bursts and shut it off for the well to recover to keep that high efficiency. On average I get about 100 gallons in 20 minutes and it drops off rapidly. I think the most I ever got using that method was 150 and the rate becomes less than a gallon or maybe nothing. So 7 watts on average. Also thats not counting inverter losses.

Here a dankoff slow pump which is not a submersible but you can get around that, at its worst rate and highest head pressure only uses about 6 watts per gallon. Keep in mind in both of these applications I am not pressurizing water. I am simply transferring it.
If my well was just a bit larger I would cram one of those just above the static water level. I've seen it done but my well necks down to 4 inches.

By slow pumping, I reduce my total head by keeping the water level up. If I can match the rate of my recharge or near it I can get more water with less effort than just pumping it near dry and waiting 24 hours.

None of that is really my problem though. My biggest issue is peak power and motor surge. Although its nowhere near 10k, I start it on a 5 KW generator. My 4 KW magnum will run it but I try to avoid that, I don't want to damage the mosfets. Best guess the surge is around 5-6 KW.
 
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Deveak

Solar Enthusiast
What does "down a valley" mean? Is the pipe exposed? Could you add a midpoint tank and pump?
My well is down a hill, nestled in a crotch of a valley. Its all buried. I am debating the midpoint tank but it would be difficult to add it anywhere but right at the well head. Reducing my head pressure but I still need to pump 200 ft uphill.
I mostly need to find a hands off way to pump water. I work a lot in the oil field and I have family members who are...technically challenged and have no idea how to use....anything.
 

snoobler

Solar Honey Badger
That doesn't sound right. My current well pump is 12 GPM and about 2100 watts. The first problem is my static well level drops as I over pump the well at a high rate. So the amps go up (a bit) and my rate drops. At best rate thats good at 3 watts per gallon but only in a perfect world.
I would need to run it in really short bursts and shut it off for the well to recover to keep that high efficiency. On average I get about 100 gallons in 20 minutes and it drops off rapidly. I think the most I ever got using that method was 150 and the rate becomes less than a gallon or maybe nothing. So 7 watts on average. Also thats not counting inverter losses.

Here a dankoff slow pump which is not a submersible but you can get around that, at its worst rate and highest head pressure only uses about 6 watts per gallon. Keep in mind in both of these applications I am not pressurizing water. I am simply transferring it.
If my well was just a bit larger I would cram one of those just above the static water level. I've seen it done but my well necks down to 4 inches.

By slow pumping, I reduce my total head by keeping the water level up. If I can match the rate of my recharge or near it I can get more water with less effort than just pumping it near dry and waiting 24 hours.

None of that is really my problem though. My biggest issue is peak power and motor surge. Although its nowhere near 10k, I start it on a 5 KW generator. My 4 KW magnum will run it but I try to avoid that, I don't want to damage the mosfets. Best guess the surge is around 5-6 KW.

Are you actually getting 12gpm?

How would you get around that? It only has 20' of suction capability.
 

time2roll

Photon Sorcerer
That is exactly what I would do to cut you head pressure from 350-400 to the 200 + 150-200.
If you could slow fill a 200 gallon tank at the well head you just pump that out once or twice a day.
 

Deveak

Solar Enthusiast
Are you actually getting 12gpm?

How would you get around that? It only has 20' of suction capability.
At full rate yes 12 GPM but it quickly drops off after 50 gallons. I timed it, I get the first 25 gallons in two minutes and the next 25 in 3. Nearing 100 gallons it takes 10 minutes to get 25 gallons.
I mean, how can you get around that it's not submersible?
I could jam it down in the pipe just above my max static water level but thats unlikely. I could also do what Nemo solar pumps do and fit a pvc shell around it and seal it up with marine sealant and submerse the pump. If you have time look it up. Its a fairly low cost and simple pump.
 
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