How To Power A Grundfos 6SQF-2?

pabloesguapo · March 2012

Not sure what to do here...

Building completely off grid, solar powered, with batteries and generator back up.
The well has been drilled about 50ft away from where I want to build the house, at approximately the same elevation (+/- 10ft).
I'm hoping to build a shed right next to the well to house the storage tank, pressure tank, and other necessary water equipment.
I also would like to use the roof of the shed to mount all my solar panels.
I believe that storing all my batteries in the basement of the house would be wiser, since the temperature would be more controllable.
Going about 50ft, I'll probably need to run 4/0 wire to the house to limit voltage drop.

I have 3 major questions:

1) How do I power my pump(s)? AC or DC? Do I power them "upstream" of the batteries on DC and only during daylight? Do I run them DC from the batteries and run 4/0 back to the pumps? Do I run an AC cable back to the shed to run the pumps?

2) Where should I place my batteries?

3) Where should I place my pressure tank(s), in the shed, or in the house?

BB. · March 2012

Re: How To Power A Grundfos 6SQF-2?

pabloesguapo wrote: »

Not sure what to do here...
Building completely off grid, solar powered, with batteries and generator back up.

The well has been drilled about 50ft away from where I want to build the house, at approximately the same elevation (+/- 10ft).

I'm hoping to build a shed right next to the well to house the storage tank, pressure tank, and other necessary water equipment.

I also would like to use the roof of the shed to mount all my solar panels.

I believe that storing all my batteries in the basement of the house would be wiser, since the temperature would be more controllable.

Going about 50ft, I'll probably need to run 4/0 wire to the house to limit voltage drop.

Don't worry about the 4/O wire run just yet...

How many gallons per day do you need (summer/winter)? A solar only pump can only pump during daylight/sunny hours. If you need more water than it can pump in a couple hours, then you may have to look at battery power.
Will there be a cistern/storage tank for your water? You may have local code for water storage (fire fighting). If you have storage, you can use a relatively simple (and small/efficient) AC or DC pump for house pressure. If you plan on using the in-well pump + storage tank, then you will have to power the well pump from battery (AC or DC).
How much power (Watt*Hours per day by season) for running your home. AC only? Some DC power too?
Will you have large loads (fridge/freezer/shop/etc.--i.e., peak watt requirement)? These will help define your solar array and battery bank sizes.
Backup genset--Have you sized/picked something you like yet?

For the Grundfos pumps, running 35 VDC will be -20% less efficient than running 120+ VAC/VDC (page 24 of pdf manual). So, choosing a 48 VDC battery system vs a 120/240 VAC inverter will work out to be about the same overall pumping efficiency (inverter will be around 85% efficient).

1) How do I power my pump(s)? AC or DC? Do I power them "upstream" of the batteries on DC and only during daylight? Do I run them DC from the batteries and run 4/0 back to the pumps? Do I run an AC cable back to the shed to run the pumps?

Again, how much water (gallons per day by season) do you need. If this was for irrigation/cistern use--A pump+solar array is really nice. No batteries, no battery maintenance/monitoring, no battery replacement after 5-10 years or so (or more often if you run them dead one day). That will tell you if you can even run solar only or not.

However, if the well is next to your home and you are running off-grid solar already--Then having a separate array that cannot be used to charge/run the home may not be the best use of cash.

Note, if you run the Grundfos pump from DC, you have the option of running from 30-300 VDC... It appears if you go DC Battery Bank, you will have to pick 48 VDC (OK?). If you do a stand-a-lone solar array (no battery for well pump), you can use Vmp-array much higher and use much smaller wire (if you had to mount the array XXX feet away from well).

Otherwise, you could also size your inverter to power the well pump (90-240 VAC)... 120 VAC is common for smaller inverters, but there are more 120/240 VAC split phase inverters coming out these days (no extra transformer). Obviously 120/240 VAC is going to require much less copper vs 48 VDC from your battery bank.

The SQF pumps are all AC and DC compatible... So, the questions I have:

2) Where should I place my batteries?

In a secure and temperature stable (~40-80F) is a good start.

Depending on the size of battery bank and the design of batteries you pick--Access may be very important. You don't want to struggle with large batteries/cells down a small stair case to the basement.

Proper design and wiring of a battery bank can greatly reduce the chance of fire--However, building a battery/solar shed (and a separate generator/fuel shed) is not a bad idea.

If you are using battery voltage (12/24/48 VDC), then having the batteries near the point of use is important to keep voltage drop low.

With MPPT charge controllers, you can mount the array a fair distance from the battery bank. So, that decouples the Solar Array from the battery shed location a bit.

3) Where should I place my pressure tank(s), in the shed, or in the house?

If the tank does not get freezing weather, I am not sure it matters a lot. Outside the home if something breaks/leaks may be handy. Put anti water hammer devices in the home at the end of the pipe runs to prevent water hammer when valves turned off quickly.

I hope others with more experience than I can address the questions of batteries/inverters in home vs shed next to the home, vs a shed 50' at the well head and what they feel works well for them.

Sorry, at this time, I have more questions than answers.

-Bill

vtmaps · March 2012

Re: How To Power A Grundfos 6SQF-2?

Like Bill, I have more questions than answers. One more consideration is grounding. Your well is 50 ft away from the house. I presume (but don't really know) that you have a ground rod at the house. Perhaps your house panels are away from the house and have their own ground rod?

When you have wires running all over the landscape you need to think about the effects of lightning. Your various ground rods (and your well is a ground rod) can be thousands of volts apart when lightning strikes in your neighborhood. I tend to favor a complete separate system for the well pump. That means the well shed should have its own ground (the well itself), its own panels, its own batteries. There should be a plastic water pipe, but no wires running from the well shed to your house. That includes control and monitoring wires. If you do want to run wires, they should be physically isolated from your general house wiring. Suppose, for example, that you want to run a set of wires from the house to the well shed so that you could charge the pump batteries from the house on occasion... those wires at the house should be disconnected (anderson connectors) from the house system when not in use. I wouldn't trust a switch or relay for the connection because lightning could arc across the switch.
--vtMaps

stephendv · March 2012

Re: How To Power A Grundfos 6SQF-2?

Personally I prefer a single system with 1 set of panels and 1 battery bank, as it's easier to manage, costs less and you can distribute the power and loads more easily.

Since you need the array, inverter and batteries for power to the house there's no need to go for the direct-solar SQF pump. If your inverter is big enough to handle the starting surge then you can use a standard AC well pump. If it it's big enough to handle the pump start surge then you could use the SQ series pump which have a soft start system.

pabloesguapo · March 2012

Re: How To Power A Grundfos 6SQF-2?

I see what you mean, more questions than answers. Let’s try to knock a few of them off.

By “storage tank”, I guess I mean cistern. It will be a 2500 gallon, above ground, green tank. As far as my contractor and I are aware, there are no codes to dictate the size of a cistern, for fire fighting, or any other reason. I just figured on my own that I should have that much water on hand, just in case, God forbid…

I plan on using 1 or a pair of one-hundred-ish gallon pressure tanks, either inside the house or inside the shed, I don’t know which. Inside the shed would eliminate the need for a booster pump to get water to the house in the first place (I think). Inside the house would eliminate the possibility of water freezing inside the pressure tanks in the wintertime (It DOES go below freezing at night regularly enough for this to be of concern).

I had no idea that the Grundfos was more efficient running on 120v AC than on DC power. I totally missed that one. I guess that solves my problem then.

So, based on your answers so far, here’s what I think would work best for me. I should set up the Submersible pump, storage tank, and pressure tanks (plus all the other accoutrements) inside the shed this summer. I will also install the solar array on the roof, and store the batteries and other solar equipment inside the shed. From the very start, I will run the sub. pump on AC power. (The shed will also be large enough to temporarily house a few other indispensible pieces of household equipment during house construction; A washer, dryer and refrigerator) Once house construction has progressed enough, I will run a big honkin’ wire from the shed to the house and store the batteries, inverter, etc. inside the house. I will also run an AC cable back from the house to the shed in order to power the sub. pump. Both the house and the shed will be groundedand breakered, of course. Would it help if I ran the wires between house and shed in a deeper trench? Double thick conduit? Might it be wise to turn the breaker to “off” whenever I see a thunderstorm approaching?

I think that about covers the basics. Thoughts?

stephendv · March 2012

Re: How To Power A Grundfos 6SQF-2?

Why not leave all the power generation equipment in the shed permanently?

pabloesguapo · March 2012

Re: How To Power A Grundfos 6SQF-2?

Because I'm worried about how the temperature fluctuations will affect battery life. It gets into the 100's (f) in the summer, into the teens in the winter.

mike95490 · March 2012

Re: How To Power A Grundfos 6SQF-2?

If you are using a pressure tank, and an cistern, you need 2 pumps, one to lift water from the well and into the tank, and a 2nd one, to keep the pressure tank "pumped up".
Filling the 2500 tank can be done solar only.
the pressure pump needs to have power all the time, or you may run out of pressure before sunrise.

erne · March 2012

Re: How To Power A Grundfos 6SQF-2?

I would suggest that you burry that tank. All your connections will freeze and break. Also the interior will freeze a few inches in during extended cold spells. It can be done easily by wire meshing the exterior and stuccoing it to keep it from collapsing. If you don't own one yet get a burial-able one. If you don’t want to do the above, put the tank inside the building. That would temper your summer tempters. You can go to the “off grid section” and read (Shed) to see how to heat your batteries in the winter. You would need a smaller system than the one used in the high mountains. It is more important to keep your battery tempters from rising than from falling. Be sure to isolate your water with a wall if you are going to have your water and electrical in the same place, a leak in one of the pipes spraying can cause havoc on inverters and other equipment. Also if your going to go with conventional wiring and a 120 volt inverter without a transformer, you don’t want any 2 or 3 way switching if you use a jumper to both sides of the 220 volt electrical box.

vtmaps · March 2012

Re: How To Power A Grundfos 6SQF-2?

pabloesguapo wrote: »

Might it be wise to turn the breaker to “off” whenever I see a thunderstorm approaching?

That can't hurt, but its not much protection either.

Inside your submersible pump are AC wires (hot, neutral) that are relative to ground at your house (your neutral is bonded at the house). Meanwhile, the casing of your pump is bonded to the well. When lightning strikes (and your house ground is thousands of volts apart from your well ground) there will be sparks between the internal wiring of your pump and the pump's casing.

When big lightning wants your equipment in a direct way, you can't really do much about it. But there are things you can do to minimize the chance of damage by neighborhood lightning. Surge protection devices (Midnite has some new ones) can help. So can having your wiring done in such a way that the pump doesn't see two different grounds.
--vtMaps

BB. · March 2012

Re: How To Power A Grundfos 6SQF-2?

As I understand, ac or dc does not matter, it is the low vs high voltage.

-Bill

solarvic · March 2012

Re: How To Power A Grundfos 6SQF-2?

One buryed tank was enough for a lifetime for me. Mine started leaking after only a few years. Also you can,t put air in the bladder. A friend of mine got a septic rank without a lid to keep his pump and tank in. let the top pf the septic tabk stick out of the ground about six inches. Built a small shed just big enough to cover tank. It gets down to past -20 f here and he told me it never froze.
:Dsolarvic:D

erne · March 2012

Re: How To Power A Grundfos 6SQF-2?

You have a valid concern about leaking, but a 1000 gal. cistern does not have a bladder in it. I would opt for putting that tank in the shed for the temperature summer moderation but it would take a very good floor, or concrete pad.

tmarch · March 2012

Re: How To Power A Grundfos 6SQF-2?

Locally we have many concrete cisterns that are over 100 years old and still work. Most are in the 1000-2000 gallon size and the top of the water might freeze but as long as the inlet and outlet are below the frost line the warm water pumped in will melt that. These were all formed and poured, the domed lid would be fun.
Most have a seperate "well pit" for the pressure tank, but that's been outdated by the pitless units on the well with a pressure tank at the well head.

pabloesguapo · March 2012

Re: How To Power A Grundfos 6SQF-2?

I am of the same mind as solarvic, in that I don’t want to bury the storage tank if I can help it. Way too much work to put it in, or to deal with any problems that may arise. While this does expose the tank to potential freezing, I AM planning on keeping it inside the shed. I COULD insulate the shed to retain heat. I COULD insulate the tanks in a variety of ways. While temperatures do go down into the teens from time to time in the winter, that’s only at night. During the daytime, from what I’ve monitored this winter, temperatures go back up to near, or at least, freezing during the day. With an insulated shed and/or tank, I should be fine. No? Thinking in terms of IPSWH's here. If I can get the temp of the water up during the day via sunlight, 2500 gallons of water shouldn't freeze to dangerous proportions overnight. (?)

Erne mentions a “very good floor”, or a concrete pad. How about machine leveled, compacted sandy/gravelly dirt? The guy I have clearing my land will prepare the area around the well for a shed if I want (at no extra charge). I would rather not spend the money if I don't HAVE to.

He also mentions building a wall. Good idea. Even if the wall gets ruined, it sure beats water spraying everywhere and ruining everything else.

Tmarch mentions a frost line. Where I am, the average soil temperature stays about 56 degrees (f). It only snows a handful of times at my elevation (3840 ft) and It never sticks more than a day or two.
I am still pretty virginal to all this. I’ve read about a pitless unit, but don’t know much… From what I’ve read, that’s basically a t-pipe submerged down a few feet so you can run a buried pipe off to your tank, right? I suppose that is to prevent freezing water by keeping the pipe below the frost line? Don’t think that applies to me, does it? Or does the pitless do more?

I'm still worried about lightning. (Thanks, vtamps!)

Could someone please direct me to some plans, drawings or something, so I can SEE how it’s all supposed to be plumbed?

Volvo Farmer · March 2012

Re: How To Power A Grundfos 6SQF-2?

If you can get even a foot or two of elevation rise from the cistern to the house, you can gravity feed the cistern into the house, then put a smallish (15 gallon?) pressure tank inside the house with a booster pump. That's how we do it anyway. The disadvantage is that you can hear the pump inside the house, but with a pressure tank, it doesn't come on every time we flush a toilet, only when the pressure drops below a specified level.

tmarch · March 2012

Re: How To Power A Grundfos 6SQF-2?

Where you are it may not freeze the ground enough to freeze pipes in winter, but I'd still bury the pipes to keep vermin from chewing on them and to allow traffic over them.
I doubt that your tank would freeze enough to hurt it in a shed, and I would go with a compacted dirt floor in case of a leak.
Personally I would bring the water out of the bottom of the tank, that will have some affect on your pressure to the house. Then just put the pressure pump and tank in the basement.

The pitless unit is a pressure tank that is also buried next to the well and water is pumped directly into that tank and from there directly to the house. It is not good for solar without battery or generator back up.

solarvic · March 2012

Re: How To Power A Grundfos 6SQF-2?

Why do you need the big storage tank? Description of a pitless well adapter. You dig around the well casing on one side the depth you want to bury the water pipe. Get someone to cut a hole in the side of well casing with a cutting torch just big enough for the adapter to fit thru the wall of the pipe. I piece with threads and a gasket fits thru the hole from inside. The outside piece with female threads and gasket screws onto the threads from the inside. The outside piece has hosebarbs that you slide the water pipe onto. Make sure you use good quality hose clamps made from stainless steel. I put 2 clamps on each joint for mine. On the pitless adapter is a third piece that you install on the end of the plastic pipe that the pump is connected to the other end down deep in the well. The piece of the adapter mounted on the inside of the pipe has a groove in the topthat is open. the piece on the pump end slides down unto that and the gravity of the pump weight holds everything together. Pitless adapter is made from brass. Just run the pipe to your house to a pressure tank in the basement with the pressure switch. Bury the pump power line in the ditch with the waterline. Bring the electric line to the top of your well casing. You should have a well cover that has a place to run the lpower line thru. If you still think you need a large tank for water storage you could put a buryed fire hydrant some where near the well off a t from the waterline going to house. You could then fill the big outside storage tank on days when you had extra power. I would just get a grundfos sq flex pump that runs off 110 ac. I have one that is suposed to take 1200 watts starting and 1100 running. That sounds like the way to go . If you are going to build a shed to put the solar panels on and keep the batterys in, why not put the inverters and charge controlers there too and only have to send one 220 ac cable to house to connect into your service panel. I have a magnum inverter that would work great in that kind of set up. all you would need to do is run a communication line from inverter to inside house hooked to a remote control. Also if you use midnight charge controlers you can have the display that controls the charge controler in the house too. :Dsolarvic:D

Texas Wellman · March 2012

Re: How To Power A Grundfos 6SQF-2?

Since you're going with the SQF series have you considered the wind power option? With wind power you could power the pump day or night and not have to worry about batteries as much.

Bear in mind that on the water storage that it will be a huge heat sink. Water here comes out of the ground at 67-72* year round so a 1,000-2,000 gallon tank would take a long time to freeze as long as you were adding a couple hundred gallons to it daily. I wouldn't worry about the large tank freezing.

It's much easier to store water than electricity. Some of the old timers used elevated cisterns with their windmills and simply used gravity to feed their house. Every 10 feet of elevation gives just over 4 psi of pressure. Not much pressure but they made it work somehow. I think they traded pressure for volume. Modern society trades volume for pressure. Get in a regular shower that does 2.5 GPM at 60 psi or a low pressure shower that does 20 gpm and you'll see what I mean.

stillchillin · March 2012

Re: How To Power A Grundfos 6SQF-2?

Pablo, I have nearly the same shed/house set up as you are considering. My well is in between my house and shed. I have my array on the shed but everything else is in my cellar. I have a SQ series 230V submersible pump in the well and a pressure tank in the basement, the pump is only a 1/2 hp. Do you know how large a pump you need( pump depth, static level) ? I ran 4 conduits from the shed to the house and have a subpanel in the shed for lights and power, My array required a pair of #2 wires and a #8 ground I ran a 1 1/2 conduit for that. Do you how large a system you will require? I would keep it simple on the water side, spend the money on panels and storage instead, just my opinion.

pabloesguapo · March 2012

Re: How To Power A Grundfos 6SQF-2?

:cool:Thanks, all, for your helpful words. A clearer picture of all this is developing for me... with the help of a few youtube videos.

I had the hardest time there for a while understanding the pitless adapter. Once I figured out that the one side of the "T" was closed---the threads are there only to attach the homemade T-wrench---the lightbulb came on. It's closed after those threads. It's not a T at all. It's an L. I get it now!

Here's how to hook it up, as I understand it. Someone please correct me if I'm wrong.

submerdible pump
torque restricter
up a pipe, or hose, to the pitless adapter
water flows horizontally now, the wires run up to the top of the casing
water into storage tank
water out of storage tank into 1 (or 2) pressure tanks.
water between storage and pressure tanks could be gravity feed, or boosted with another pump (or 2, if I have 2 pressure tanks)
I can place the pressure tanks inside the shed, or inside the house. My choice.

Sound right so far?

Beyond that, I get lost in knowing what types of valves and stuff I need. Check valves? Pressure relief valves? Vacuum something or others? ???????????????

westbranch · March 2012

Re: How To Power A Grundfos 6SQF-2?

quality pumps usually have a check valve built in. you might want one at the gravity tank to keep the water in if working onthe supply. Check valves stop 'reverse flow'.
Relief valve relieves excess pressure and is not needed if pumping into an open top tank used for gravity feed. you just need a shut-off device like a toilet tank shutoff. just that it shuts off the power when full

HTH

solarvic · March 2012

Re: How To Power A Grundfos 6SQF-2?

http://www.buyeagle.biz/page.asp?id=2&catid=154&prodid=6092 Yes I think you got the pitless adapter figured out now. IT is 3 pieces i inside the well casing, i outside the well casing and the rhird piece connects to pipe that is on pump. The threads are for screwing a piece of pipe into to lift pump out of the pitless adapter. If it was me I would put a fire hydrant inline to the pipe and keep the pump in the house. the website shows you what the fire hydrant looks like. If you wanted 2 pressure tanks you could just connect your well pipe to first tank and pipe out of that tank to second tank with the pressure guage and switch on it and connection to your plumbing system. I am thinking of putting a second tank in my own system so the pump won,t have to cycle as often. Do you need the large storage tank for fire protection or are you worryed about the well not outputting enough gal per minute. That fire hydrant won,t freeze in the winter. When you turn off the valve the water drains back in the pipe below the ground. :Dsolarvic:-)

pabloesguapo · March 2012

Re: How To Power A Grundfos 6SQF-2?

Do I need a pressure relief valve anywhere then? before/after my pressure tanks?

Yes,I am worried about fire protection, for one thing. The nearest fire department is a volunteer dept. about 8 miles away. After that, it would be a muni FD about 25 miles away.

I also want extra water on hand because I want to irrigate several acres for horse pasture and also for large gardening. I don’t think running a hose and sprinkler downstream of the pressure tanks is a good idea once I really get going.

“I would put a fire hydrant inline to the pipe and keep the pump in the house.”

Huh? Where inline exactly? Not following. I’d like to have some sort of way to irrigate without drawing water from the house’s pressure tanks. This hydrant is hand pump. Can I do something with a non-hand pump?

"If you wanted 2 pressure tanks you could just connect your well pipe to first tank and pipe out of that tank to second tank with the pressure gauge and switch on it and connection to your plumbing system".

So, after my STORAGE tank you mean?

pabloesguapo · March 2012

Re: How To Power A Grundfos 6SQF-2?

Eureka!!!

I found what I was looking for. Pretty simple. I knew it would be. I'm nothing if not persistent. My wife would call it stubborn.

http://www.cleanwaterstore.com/technical/water-treatment-diagrams/well/stank_bpump_ptank.html

That's it in a nutshell.

Solarvic, if I were to add a second tank to this, where would I install the extra pressure switch and gauge you suggested, if any at all? between the tanks, or after them both?

To satisfy my irrigation needs, I THINK all I have to do it "T" off the main pipe between storage tank and that first booster pump with another pipe running to the yard, powered by another booster pump. The right pump should provide sufficient pressure to water a big lawn, pasture, or a few rows of veggies at a time, no?

westbranch · March 2012

Re: How To Power A Grundfos 6SQF-2?

Relief valve? probably not as the pressure switch for turning the pressure pump on/off will stop pumping at ~ 60 psi, kicks in at ~ 30 psi... UNLESS you have a vertical drop in elevation in excess of 150 feet from the holding tank (cistern) to the tap or ??

HTH

solarvic · March 2012

Re: How To Power A Grundfos 6SQF-2?

http://www.buyeagle.biz/page.asp?id=2&catid=154&prodid=6092 This is not a pump. It is a valve that is underground so it won,t freeze up. The lever is just for turning valve on and off. You would put a short piece of pipe out of your pitless adapter then a TEE with the pipe that run to your house and then to your pressure tank in house. The hydrant would stick up out of ground. You could run a hose from the hydrant to tank and fill the tank when you had excess power. I wish I had obe of those hydrants but I would have to dig down about 5 or 6 ft to get to my waterline and don,t feel that ambitious. I got the idea from the new houses across the road from me. Mt daughter has the firehydrant between the well and house and they keep a hose at the hydrant to water thier garden with. You only need the submersable pump for water pressure to home and to fill the tank. Looks to me that you might be complicating things too much by having all the separate pumps. :Dsolarvic:D

How To Power A Grundfos 6SQF-2?

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