Choosing the Best Well Pumps for Off Grid Homes

July 13, 2016 · 10 comments

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If you are not careful when designing your off grid water pumping system, your pump can be the single largest load on your solar, wind or micro hydro power system.

water pumping in an off grid application

 

The best way to provide water to your off grid home is to not use a pump, if possible.

But since that is not always possible, we will discuss the best pump options, why they are used and how to make them more energy efficient.

We have a 200 foot (67 meter) drilled well next our home (in the middle of our driveway due to poor planning) and our well overflows at about 1/2 gallons per minute. Very cool that it overflows but totally unusable by itself to provide our home with potable water because it is just at the level of our bottom floor, only produces 1/2 gallon per minute (2 liters per minute), and is under almost no pressure at all.

In fact this overflowing water creates a big nuisance as their is always water pooling outside our home in the driveway in the summer and always ice building up in layers within a 15 foot (5 meter) radius of our well casing making our driveway unusable.

However there is one advantage and that is the water is very easy to pump using a shallow well pump even though our entire well is 200 feet (67m) deep.

We actually use a submersible pump called the SQFLEX made by Grundfos. It is connected at 120 volts and has an AC/DC permanent magnet motor with no surge start up. They actually can operate on 30-300 VDC or 90-240 VAC at 50/60 Hz with no extra components. Their internal electronics are designed to operate AC or DC and over a wide range of voltages.

However you will get much more water at a higher pressure as the voltage increases. Ours is designed to pump 10 gallons per minute at 200 feet of water depth. It just happened to be the model we could find at the time and 10 gallons per minute is far more water than we could ever use.

THE SQ FLEX by GRUNDFOS (click to make bigger)

sqflex diagram


dankoff solar force pump off gridWATER PUMP GOALS FOR THE OFF GRID HOME

#1    Obviously we are trying to find a pump that will do the job but use the least amount of electricity.

#2    Our second concern is to limit the surge of electricity required when the pump starts if you have a small to medium sized inverter. All electric pumps surge when they first start up except a newer type of pump called a no surge or slow start pump.

#3    Positive displacement pumps are generally the best choice for off the grid homes as they use less energy per liter or gallon of water pumped.


CHOOSING THE CORRECT TYPE OF WATER PUMP

Looking for circulating pumps?

The first consideration when planning your pumping system is the depth of the water in your well. We must know the static water level as well as the dynamic water level.

The static level is easy…

STATIC WATER LEVEL is the level of the water in your well when it is sitting there doing nothing (or the pump is not on).

The dynamic water level is much trickier to verify. It is the lowest level of the water in your well after being used as on a normal day.

In other words…

DYNAMIC WATER LEVEL is the lowest level the water will be in your well while you are using that water.


WE MUST USE THE DYNAMIC WATER LEVEL WHEN SIZING PUMPS AND DECIDING WHAT TYPE OF PUMP TO USE AS THE DYNAMIC WATER LEVEL IS THE POINT AT WHICH THE PUMP YOU CHOOSE IS WORKING THE HARDEST!


SHALLOW WELL OR DEEP WELL

Generally if your well water is less than 25 feet below grade (ground level) it is considered a shallow well.
A shallow well will require a piston pump (driven by either AC or DC motor), shallow well centrifugal (jet) pump (driven by either AC or DC motor) or shallow well hand pump.

If your well’s water is over 25 feet down it is considered a deep well.
A deep well will require either a deep well submersible (AC or DC), deep well jet (centrifugal) pump or deep well hand pump.

THE DEPTH OF THE WELL IS IRRELEVANT,

THE DEPTH OF THE WATER IS WHAT COUNTS WHEN CONSIDERING WHETHER YOU NEED A SHALLOW WELL PUMP OR DEEP WELL PUMP!


brass foot valve with screen

FOOT VALVES

All of the pumps mentioned below will need a foot valve installed at the end of the suction pipe to keep the pipeline and pump full of water making it only necessary to prime the pump once.

Foot valves are basically a one way valve or check-valve made of plastic, brass or stainless steel that have a plastic or stainless screen on the end to stop large sediment from entering the water system.

Brass and stainless foot valves are the most rugged, but plastic usually work fine in shallow wells.

They allow water into the pipeline but do not allow the water to drain back out of the pipeline.


SHALLOW WELL WATER PUMPS

If the level (static and dynamic) of your water is less than 25 feet, you can and should use a shallow well pump. This pump could be a hand/manual pump, centrifugal pump, piston pump with an AC motor or piston pump with a DC motor.


Hand pumps are great for shallow wells in an off the grid situation.SHALLOW WELL HAND PUMPS

Hand pumps or manual pumps are exactly what they sound like.

They operate with human power. No electricity required. You can either have the pump mounted at a sink and pump water when needed to fill up the sink or pump the water in containers at the well head.

The closer the water is to ground level, the easier it is to pump the water.

As the water level approaches 20-25 below grade, it becomes very difficult to pump water with a hand pump.

You must install a foot valve at the end of your water pipe to keep the pipe and pump full of water to make it unnecessary to prime the pump each time it is needed.

hand pump for off the gridADVANTAGES:

  • inexpensive
  • easy to find in any hardware store
  • parts are easily obtained
  • use no electricity
  • EMP proof

DISADVANTAGES:

  • labor intensive
  • only water available at the pump
  • difficult to connect to typical house plumbing
  • the deeper the water, the harder it is to pump

SHALLOW WELL JET (CENTRIFUGAL) PUMPS

Using a shallow well pump for off grid homesThe most inefficient (but least expensive) choice for the off grid home shallow well water pump is the jet or centrifugal pump. They are usually mounted in the home or in a pump house and usually close to the well. They work well with dug wells and very shallow drilled wells. As they are a shallow well pump, the lowest water level MUST not be more than 25 feet deep.

As they are not a positive displacement pump, they use more electricity per liter or gallon of water pumped.

Shallow well jet pumps can have 1/3, 1/2, 3/4 and 1HP electric motors attached to them. The larger the motor, the more water will be moved per minute. However, being off grid it is best to stay at 1/2HP or less to keep the operating and surge current to a minimum. We have tried adding DC motors to shallow well jet pumps and although it is doable, the motor and pump must be lined up perfectly or vibration and early pump/motor wear will result.

As there are many, many brands that vary from North American, European, Asian, Australian to African. Some are decent quality and some are junk.

plastic pump impellerIf they have a plastic impeller (most common) they are not made to last. If they have a brass or stainless impeller, they are likely to last longer.

As we are looking for the most efficient pump we can afford, the jet pump is usually not the best choice. However, if money is tight you can buy these pumps for as little as under $100 US.

ADVANTAGES:

  • inexpensive
  • easy to find in any hardware store
  • parts are easily obtained
  • stainless impeller for jet pump off gridplumbers are familiar with these pumps

DISADVANTAGES:

  • very inefficient (energy hogs)
  • very noisy (problem if installed in home)
  • large start up surge (3-6 times operating current)
  • will not tolerate dirty water
  • usually do not last more than 5-10 years
  • require a huge inverter to start depending on size of motor
  • only operate with 120/240 AC 60hz or 230 volts AC 50hz

SHALLOW WELL PISTON PUMPS

using a piston pump in an off grid homePiston pumps are awesome for shallow well water pumping.

(The photo to the right is a DC piston pump made by Dankoff Solar.)

Piston pumps can be operated by:

  • AC motors
  • DC motors
  • fossil fueled engines
  • small steam engines
  • human power

As long as the pulley/wheel on the pump turns, water is pumped.

That is the beauty of a positive displacement pump.

used piston pumps for off the grid livingThe most common brands of piston pumps are DURO and POMPCO.

They can be picked up used at yard sales, eBay, Amazon, classified ads and online for anywhere from $30-$250 US.

Once you own the pump itself, you can install whatever motor you want to drive it.

 

PLEASE NOTE: You can either use a v-belt (like an old style alternator belt) or you can use a cogged belt (like an automotive timing belt) to run your pump. The v-belt will be easier to buy, quiet and less efficient. The cogged belt will be the most efficient, difficult to find and the loudest. Timing belts/cogged belts are extremely noisy.

cogged belt

This way you can make a very efficient piston pump for very little money.

New piston pumps are a great choice as well if you can afford them. Below are two different quality POMPCO piston pumps made with 1/2HP AC 120 volt 60hz motors. You can use them “as is” or you can remove the motor and install your own.

pompco piston pumps for solar homes

Both Pompco and Duro make excellent quality pumps that are easily rebuild-able or repaired using kits that can be purchased almost anywhere in the world.

Dankoff Solar makes beautiful piston pumps called “Solar Force” that are powered by belt (v-belt or cogged belt) driven DC and low surge AC motors. They are probably the best choice for a shallow well if you can afford them.

The DC models can be 25 to 75% more efficient than an “off the shelf” centrifugal pump. They also make no surge AC piston pumps if you prefer AC. Dankoff makes 12, 24 and 48 volt DC pumps as well as 115 VAC 60hz and 230 VAC 50hz models. They are excellent quality.

dankoff solar force piston pump

ADVANTAGES:

  • repair kit for piston pump for solar or wind powered homes.inexpensive (if you buy used and build yourself)
  • very efficient
  • easy to find online
  • parts are easily obtained
  • plumbers are still familiar with these pumps
  • low start up surge
  • should last over 20 years with clean water

DISADVANTAGES:

  • can be very noisy (problem if installed in home)
  • AC models require an inverter

DEEP WELL WATER PUMPS

If the level (static and dynamic) of your water is more than 25 feet, you can and must use a deep well pump. This pump could be a deep well hand/manual pump, AC jet pump, AC or DC submersible pump.


deep well hand pumpDEEP WELL HAND/MANUAL PUMPS

Even though your water level is below 25 feet down you can still use a manual pump.

Deep well hand pumps have the pumping mechanism down below the water level with a rod connected to the lever/handle above grade. They can pump down to about 300 feet (90m). The depth of your water will decide the flow rate of your deep well manual pump.

These are generally mounted outside as the pumping lever can be quite long and are usually used for those in the developing world. They are hard work.

At 90 meters of depth you can expect about 10-16 liters per minute if you can make 40 strokes per minute. You would need at least two people to accomplish this but in places like Haiti, under developed countries in Africa and other poor nations, it can mean the difference between life and death.


DEEP WELL JET (VENTURI) PUMPS

This is a special type of pump that can also pump water from a deep well but some of the pumping mechanism is above grade and some is down at the water level. It is likely the least understood pump of all the home water pumps.

The pump sends high pressure water down one of the pipes to the bottom where it is funneled into a small jet and directed into the other pipe. The jet of water essentially pushes well water up the other pipe and into your water system.

deep well jet pumps are not the best for off the grid situations

You can Google “deep water jet pumps” if you want to learn more. Just know they are horribly inefficient as they must pump a huge amount of water to move a small amount of water up to your water system. You will usually see 1/2, 3/4 and 1HP AC motors on these pumps even though they only pump a small volume of water. You can recognize a deep well jet pump compared to a shallow well jet pump by the amount of ports (or outlets) on the pump. The shallow well pump has one hole (suction) and the deep well has two (one for pressure down and one for suction) as seen in the photo to the right.

deep jet pumpADVANTAGES:

  • inexpensive
  • easy to find in any hardware store
  • parts are easily obtained
  • plumbers are familiar with these pumps

DISADVANTAGES:

  • can be very noisy (problem if installed in home)
  • VERY INEFFICIENT
  • only operate by AC  (require an inverter)
  • huge start up surge
  • a lot of electricity to move a small volume of water
  • only last 5 to 10 years in clean water

AC DEEP WELL SUBMERSIBLE PUMPS

The AC deep well submersible pump is likely the best choice when you have a deep drilled or dug well.

But you cannot just go to your local hardware store and buy what is “off the shelf”. You will need to do some research and find the correct pump for your needs.

The typical AC deep well submersible pump usually surges at between 5 and 10 times its operating current making it unusable unless you have a high wattage inverter with a decent surge capacity. If you look at the ratings of a pump like the one on the right you will see something like:

Deep well submersible pumps have a high start up current.

VOLTAGE: 120 VAC
OPERATING AMPS: 6.5

At first glance you might think this pump only needs 780 watts to operate and you have a 2000 watt inverter. Sounds great!

But because you bought an off the shelf model this pump will require 3900 watts-7800 watts to start the pump as the motor is contained in a small cylindrical shape. The surge is only for a fraction of a second in most cases, but if your inverter doesn’t have the surge capacity, the pump won’t start and your inverter might blow up or simply shut down.

ADVANTAGES:

  • inexpensive
  • easy to find in any hardware store
  • parts are easily obtained
  • plumbers are familiar with these pumps
  • quiet

DISADVANTAGES:

  • VERY INEFFICIENT
  • only operate by AC  (require a large inverter)
  • huge start up surge
  • a lot of electricity required to move a small volume of water
  • last 5 to 20 years in clean water
  • must be removed from well for repair

AC/DC DEEP WELL SUBMERSIBLE PUMPS

The SQ Flex deep well submersible pumps by Grundfos are in a category of their own. All of the disadvantages of submersible pumps are gone and replaced with amazing features.

They have no surge and can operate from a 1000-2000 watt sine wave inverter.

deep well pump for the off grid home

Grundfos SQ Flex AC/DC submersible pumps have the following advantages over an off the shelf pump:

  • no surge start up
  • operates on 30-300 VDC or 90-240 VAC 50 or 60 hz
  • maximum current 8.4 amps
  • not hard to locate (anywhere Grundfos is sold)
  • can be installed vertically or horizontally (for use in shallow wells as well)
  • overload protection
  • over temperature protection
  • under or over voltage protection
  • run dry protection (optional)
  • MPPT (maximum power point tracking)
  • extremely efficient
  • can operate directly from solar modules

DISADVANTAGES:

  • expensive

For a complete guide to Grundfos’ SQ Flex pumps click here.


THE MOST COMMON AND DISASTROUS MISTAKES:

Buying the cheapest pump you can get – Cheap usually means inefficient, poor quality and short service life. You get what you pay for and cheap, plastic water pumps are more frustration than they are worth.

Using an off-the-shelf AC submersible pump – Off the shelf AC pumps have high surges when starting up and are designed to pump massive quantities of water. Plumbers do not want to hear any complaints from their “normal” clients so they make sure their pumps move huge quantities of water. However as we are trying to minimize electricity usage “off the shelf” pumps may not be the best choice unless we know exactly what we are looking for. Look at the SQ Flex by Grundfos.

Using a pump much larger than is required – As mentioned above, plumbers want happy customers so they almost always try to sell them a pump that is far bigger than required. This results in less customer complaints but more energy usage.

Using a cheap DC submersible pump – DON’T DO THIS. Shurflo comes to mind. They do not last, do not perform at all like they are supposed to and customer service is difficult to come by.

Choosing the wrong voltage pump – In the early stages of solar system design many folks assume they will be using a 12 volt battery bank and therefore install a 12 volt DC pump. The problem with this is when your system grows and you are forced to go to 24 volts or 48 volts for your battery bank. Now your 12 volt pump is useless and must be swapped with the proper voltage pump. Try to plan ahead and skip 12 volts. Go directly to 24 or even 48 volts unless you plan on having a tiny power system forever.

Buying your pump before you have your well – Before your well is dug, drilled or otherwise, it is impossible to predict what type of pump you will need. Only once your water source is found are you ready to make a decision on a pump.

Please comment below…

Leave a Comment

{ 10 comments… read them below or add one }

PPB October 16, 2016 at 8:44 pm

I found this article to be a very useful one. It perfectly outlines options, advantages and disadvantages, and may save a lot of time of preliminary research. Especially for those who new to off-grid challenges. Thanks!

Reply

Jody Graham October 17, 2016 at 10:57 am

Thanks so much for your kind words. I appreciate it!
Jody

Reply

David Ken July 19, 2016 at 6:18 pm

Hello,
Please advise if you do carry any of the following items available in stock and also let us know the asking prices as well.
1, 245 WATT AND 255 WATT SOLAR PANEL
2, Grundfos Submersible Pump 230V 22SQ15-220 1.5hp 22GPM (Part Number #: 96160158)
3, Grundfos SQFlex 11-2 Submersible pump (part no 95027335) & SQFlex CU 200 control box
4,Lorentz solar pumps – PS 150
5,Lorentz solar pumps – PS 200
6, Lorentz solar pumps – PS 600

Looking forward to hearing from you as soon as possible.
Best regards
david

Reply

Jody Graham July 21, 2016 at 9:28 am

Hi David,

Thank you for your communication. Unfortunately we are a purely informational website meant to help others in their quest to live off the grid. At some point we may focus on product sales but at this point there is nothing I can offer. Sorry…Jody

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Mike July 14, 2016 at 8:31 pm

4000watt inverter, 1/2 hp 120vac deep well pump, capacitor start. 25′ static water level, pump at 225′ below static water level,.well drilled to 425′. 85 gallon pressure tank installed to reduce amount of starts. 9.5 running amps. Has been in service for over 15 years. Totally off grid home in western Massachusetts. Off grid works.

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Jody Graham July 14, 2016 at 10:03 pm

Hi Mike,

Thanks for your input. Couldn’t agree with you more. You must be running a Trace/Xantrex SW inverter if you were operational 15 years ago. That was our second and third inverter. Loved them. Wish I had kept them for spares instead of selling them used. Had two as we upgraded from 24 volts to 48 volts. Nice big pressure tank too. Very smart! Please tell us more about your system if you have a chance. Thanks again…Jody

Reply

Mike July 23, 2016 at 12:12 pm

Jody, Thank you for your interest in my system. House was built with being off grid in mind. 10- 130 watt, 24vdc Siemens mono crystal panels mounted on shed. Angle of array set at 42 degrees all year long. 24 – Trojan T-105’s in basement. Refrigeration is by 15cf crystal cold propane refrigerator. Heating is supplied by two empire direct vent heaters. No electricity is needed to run these appliances. Whole house is wired for 120vac except for the bed room ceiling fans and night lights. The inverter goes into search mode most of the time. Most people who visit do not even know that they are in an off grid home. We have satellite TV and wireless internet.

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Jody Graham July 28, 2016 at 10:53 am

Awesome setup! Are you actually using the old Trace/Xantrex SW inverter? If so I am jealous!!!

That is also awesome your inverter is going into sleep mode in these days of most folks having 10-20 appliances, cell phone chargers etc. plugged in ALL THE TIME whether they are using them or not.

You have proved off grid living can be done without living in the stone ages. Do you shut the WiFi down at night? Great work Mike…Jody

Reply

Mike July 28, 2016 at 7:50 pm

Jody, same old reliable Trace inverter. Wondering about longevity. Internet is still an issue for off grid. We have no wires coming to the house so it’s all through the air. What I use is the Verizon “Jet Pack”. That runs on a small adaptor or Internal battery.anyone can log on. At night everything is off. Cell phones( with internet) for alarm clocks, that are charged in the car when going to work or when watching tv. You just have to think about the most efficient way to use your power. Everything on power strips. Laundry is done during daylight hours, so the batteries have time to charge before sunset. Snow cover is the only problem, but that’s a couple of seasons away.

Jody Graham July 29, 2016 at 12:41 pm

Awesome. I’d expect 30 years out of an SW as long as it stays clean and dry. They actually built them by hand back then in Arlington, WA. There was no cheap crap installed in them. They worked really hard to build something robust and with a decent sine wave…something that had never been done before. Plus they didn’t focus on profits like all of the other companies who have bought Trace only to try and make more money for the shareholders. That is the reason some of the Trace guys revolted and started Outback. If I was to buy an inverter today it would be a tossup between Outback and Magnum. Outback certainly has more sex appeal but the Magnum MS series is every bit as tough. My only complaint I ever had with the SW was the difficulty in repairing them. They are a nightmare to replace parts on. The newer stuff is more like our old computer towers. Everything is built on circuit boards. If a board goes bad, you simply replace that board most times without having to remove the inverter from the wall (although it is much easier when removed from the wall).

I hear you on the snow removal. I am working on a DC alternator that would push power back through the modules and heat them up to melt the snow. It takes a tremendous amount of energy but saves me from risking my life. It has been done by others and does work well.
Keep up the great work..Jody

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