Off grid water well

oil pan 4 · May 2019

The water coop has a lot of water outages and they raised prices. The surcharge is $55 now.
Starting to think I am done with them.
I already spent $900 getting the old irrigation pump pulled out.

Now I'm mostly concerned with just getting the water to a non pressurized surface tank.

So far this is what I have to work with:
My little battery.
https://forum.solar-electric.com/discussion/353760/new-24v-deka-255ah-forklift-battery#latest

Morningstar tristar mppt, only 15 amp. Probably add a 2nd one.

A 16 inch bore diameter well. The well depth is 120 feet. With water at 108.
I had the well cleared out and tested it did about 100gpm for 90 minutes.
It's a big well with a 12 feet of water in it so I can put just about anything I want down there.

7.3kw worth of used 295w poly 72 cell panels.
(Obviously I won't need any where near 7.3kw, maybe 3 or 4 of those 295w panels at the most)

I would like to install 2 pumps for redundancy. One that can run 24v off the battery through the charge controller. Or more likely a relay slaved through the charge controller. This will allow me to pump some water any time.

A second pump that can run straight off solar panel voltage. Which will probably be around 36 or so volts at max power and maybe 42v ocv (the panels are rated for 44.5v ocv but I have yet to observe more than 42. This will pump water and fill the tank incase the battery gets drained or my cc fails. I also plan to use more water during the day.

I'm thinking the 2 DC pumps will just be little cheap submersible units.

Then incase of emergency, say lightning takes out my pumps or something a all plastic pneumatic diaphragm pump for the non electric backup. Something like a husky pump made by graco and wheel my gasoline powered air compressor out to the well house.

Then I will use 12v RV diaphragm surflo and Delavan pumps to pressurize the water.

I would also like to dabble in rain water catchment. I have our old spa in a box portable hot tub, which I spray foamed and made nonportable. It holds about 250 gallons.

What would you do?

Estragon · May 2019

Personally, I wouldn't look forward to hauling 120' of pipe and "cheap DC submersible" pump up the well regularly, and would spend some money to avoid it.

Tecnodave · May 2019

At 105 feet pumping head you will need a pump capable of 60-70 p.s.i. to get decent flow, cheap pumps are not capable of this, solar direct pumping requires a special pump and current booster controller.

littleharbor2 · May 2019

Eagerly awaiting any and all info on solar direct pumping. Looking at a similar scenario. similar head in our Campo in Baja. I'm donating the panels to the cause. I was thinking of 600 watts with one of the higher end solar direct pumps and controller boxes.

Tecnodave · May 2019

There was an advert on Craig's list San Francisco offering to sell a set of 6 Sharp NE-180 panels and a 36 volt DC water pump for deep well. I offered but was refused, might still be there, seller was located near Fresno or east of there, don't remember all the details, but was listed wide area, including Santa Cruz. System was NIB. Forgot the other details

littleharbor2 · May 2019

Tecnodave said:

There was an advert on Craig's list San Francisco offering to sell a set of 6 Sharp NE-180 panels and a 36 volt DC water pump for deep well. I offered but was refused, might still be there, seller was located near Fresno or east of there, don't remember all the details, but was listed wide area, including Santa Cruz. System was NIB. Forgot the other details.

I'll look around, Thanks

Tecnodave · May 2019

Littleharbor,

I frequent Craig's list and will keep a lookout, it was a grower who had it for sale.
David

littleharbor2 · May 2019

I came across a new set up on CL, San Francisco for $700.00. Not sure if this is a different one but they had a Texas phone number and were listing it in multiple cities. RED FLAG! I inquired, asking about these issues and haven't gotten a reply.

billybob9 · May 2019

The well pump pressure tank is the most important item in long life for your well pump. If the bladder is shot the tank will totally fill with water and your pump will activate every time you drain the line. I recently replaced mine and redid some of the PVC to allow a gravity feed into the system ( with shut off valve )for emergency water. Some people in this area still go for the old non pressurized tank and do a gravity feed just to avoid the expense of a pressure tank. In Baja most of the wells close to the Sea of Cortez are not drinkable water but just used for general use. In some campos a fire hose and a P-100 is used to fill water tanks straight out of Sea and up to a tank for gravity feed. Using sea water to flush toilets is hard on metal parts but now most are plastic anyway.

BB. · May 2019

Is this a "Darely" P-100 pump you have seen used? (just out of curiosity):

https://www.darley.com/pump-guide/product-portable-diesel/2be10ydn-navy-p100

-Bill

billybob9 · May 2019

I just looked up Darely and YUP that's the one. It's been around for a long time and still looks the same..

oil pan 4 · May 2019

There is not going to be a pressure tank at the well head. The submersible pump just has to get the water to the surface to a holding tank.
I will have a pressure tank, just not pressurized by the well pump.

billybob9 · May 2019

Sounds like a good Idea if ever your submersible goes down you still have water in your holding tank. If it were at least 500 gallons that would last long enough to fix the problem. When I talk to the people at Farmer Supply about things like this they just give me that look. What size tank is the one that is pressurized and what is max PSI ? Thanks....BG

oil pan 4 · May 2019

I'm probably going to get the biggest pressure tank at lowes which is 86 gallons.
Normal pressure will probably be set at 65 psi.
I will probably have a timer that will temporarily crank it up to 75 to 85 psi as needed like for car/tractor washing.
55psi at 7.5gpm and 40psi at 10gpm.

I will at least have a 250 gallon tank and probably a 500 gallon tank too.
I might use the 250 as a setteling tank for rain water collection.

Basically I would like to be able to exceed the performance of utility water.

MichaelK · August 2019

What I would do is install a high voltage DC pump using 3-6 of your panels wired in series. You really strikingly increase the pump's performance as you get the pumps running above 100VDC. Grunfos has a lot of information to design a system that meets your needs. You can go here to get all the information you need.

https://us.grundfos.com/products/find-product/sqflex.html#brochures

If you want to have two pumps down the bore, I'd go with a single high V DC pump running directly off a solar pump controller, and a standard 240 VAC pump. You could easily power a 2hp pump with a 6848 Schneider invert, or an Outback 8000; with 5 or 6 arrays of your panels wired in a 3S5P, 3S6P. Then, some day when the grid finally catches up to you, you can just wire it in.

I would very greatly increase your water storage capacity. You're talking hundreds, but I would store thousands. A poly 3000 gallon tank doesn't take too much space. You might find ag tanks nearby at reasonable prices. Do you have any elevation on your property so you can set up gravity feed? That is, position the tank at the highest point on your property, pump into it, then let it drain downhill to your spouts by gravity. What are your winter lows? How much irrigation water would you consume in a week? What are your summer/winter water needs?

I have two 5000 gallon tanks that I try to keep completely full. I irrigate my orchard trees weekly in summer, which consumes about 2500 gallons per watering. That just so happens to be the same amount of water my AC pump can pump in a day, run solely off solar.

Off grid water well

Comments

Categories