anyone know much about grundfos sqflex submersible pumps

[BullCreek]

The title says it all.  I'm a retired engineer who bought a ranch near where I grew up in Texas.  We have several old windmills that are worn out/falling down and in need of replacing or alot of maintenance above and beyond the regular maintenance which is plenty, particularly because they are in hard to get to locations.  I like submersible pumps for their maintenance free nature, and have been looking at the grundfos sqflex line.  I called the local distributor today, and while he had some knowledge, it was mostly of just their canned solar solution.

To get the amount of water I need, he wanted to sell me 8 110 watt grundfos panels @ $1275 each, then two 4 panel trackers at $1700 each.  The grundfos panels are special in that they are high voltage ( can't remember, but I think he said around 100 volts).  Seems like a ridiculous amount of $$$ per watt to me though.

I'm wondering about just using some normal 12 volt panels in series or a DanB style wind turbine.  Grundfos use to sell a SWP H80 900 watt turbine kit, but the distributor said they had discontinued it, because it often went over the 300 volt maximum the pump allows and fried the motor.  According to the spec sheet for the pump:

Operating voltage range = 30-300VDC

Max power consumption = 900W

Max current = 7A

I have six BP125 12V panels I could use as a test, which in series would give 72V nominal and around 140Voc.  Their Imp is 7.1A which is just a tad higher than the 7A listed above.  The pump says it has a built in MPPT so I assume it would pump just as much water at 72V as it would at the 100V or so the grunfos panels put out in parallel, total watts available being equal.  Cost wise, this would be much more affordable, something along the lines of:

Grundfos Canned Solution                My Panels and Homebrew Tracker

8. panels @ 1275 = $10,200               6 BP125s @ 565 =  $3,390
   
2. trackers @ 1700 = 3,400               Parts for tracker    300
   
   

SQFlex 11 SQF-2 =   1,550               SQFlex 11 SQF-2 = $1,300

                  $15,150                                 $3,990

Alternatively, I think it would be even cheaper to build a DanB style turbine to power it.  Anyone know how to figure if the 300V upper limit would be a problem with an axial flux machine like that (I think I may post a seperate question on this in wind if I don't get any answers here)?  Surely if you wired the stator for cut-in at the 30V, it wouldn't get to 300 before furling.  Thoughts?

[RogerAS]

Bullcreek,

Why are you set on these pumps? You could do better $ wise with standard panels, batteries, inverters and 220 pumps. Look around and see if I'm not right. I'd forget the specialized pumps, their panels, and go for it on my own.

Free advice and worth every penny:-0

RogerAS

[BullCreek]

The only inverters I know of either require batteries (Outback, etc.) or grid-tie (SMA, etc.) - neither of which are available/suitable out in the boonies.  Am I missing something?  I'll agree with you though - that 220 standard submersibles probably can't be beat for cost/reliability where you have grid power available.  --B

[altosack]

Hello Bullcreek,

The problem with using a wind generator is that you have to have batteries to clamp the voltage so it won't run away in high winds. Even though you could certainly build a wind generator that would not exceed the 300V limit, it will still need batteries; the pump will not work as a voltage clamp.  I think this solution (with batteries) might still be the way to go if you had other needs for the electricity, and you had to buy the panels.

However, it sounds like you already have the panels you need (if the pump draws 900 W max and 7 A max, this sounds like 130 V to me, which is a bit higher than your panels will provide at the MPP (probably 95-105 V, depending on the temperature), and you might find that this will give you all the flow you need.  At the most, you could add one or two more panels to give you a full 900W in full sun at 100F (or whatever your design conditions are), but you should only do this if you aren't getting the flow you need.

I am curious: you said that the pump draws 900W max; did the dealer who wants to sell you this stuff go through the calculations with you to show a gpm/installed watt curve based on your available sunlight so you can size it to what you need ?  How did he come up with the number of panels you need ?  If he didn't show you this curve, I would find another dealer.

I disagree that an inverter/220V pump would be the way to go; I don't like my water to be dependent on my inverter, unless I've got two, which gets pretty expensive (suitable inverters would run $1800-2500 each; you need inverters with great surge capability for a 220V pump, plus a transformer for 220V). If you've got a big water tank that can get you through inverter repairs, maybe.

I have some indirect experience with this, but I think you should find a local dealer who can give you the answers you need honestly; it sounds like the one you have is a little too interested in a big sale, or else he doesn't know what the pump really needs. Either way, I'd get a second opinion.

Best of Luck,

Dave Voss

[RogerAS]

Bullcreek,

Well they DO make 110V deepwell pumps. A couple weeks ago I helped my neighbor pull his (bad foot valve), not submersed, and was 265 feet down. His only used a 3/4 HP motor. So a good option might be something like that. I don't know how deep your wells are so.... Still a few batteries and a good 110V inverter (2500W>) would be a cheaper option.

I assume these pump to those holding tanks with a float valve that shuts off the pump when full. Depending on the # of cattle, and well depth, maybe a pump like my neighbors might keep up. I never have liked the idea of sending 220V down into water. I don't know why.

I currently have to haul my own water, and that really bites. Our next step is to get a well drilled and then I'll face this issue personally. At any rate good luck.

RogerAS

6 years off-grid & lovin' it!

[BullCreek]

I didn't mean to snub your reply, I guess my fears/apprehension about an inverter based solution were similar to those expressed by altosack above plus cost.  Batteries and an inverter would add alot to the cost/maintenance making wind more expensive than solar - plus we have alot of lightning here, which would worry me at $1800 a pop for an Outback inverter.

As far as your other question about how deep the wells are in my "wind" thread - similar to you - around 200 ft.  I used to have a relative that was an experienced well man who would have been quite helpful in this endeavor - unfortunately he passed on about a year ago.

Thanks again for your comments.  --B

[elvin1949]

Bullcreek

 Check out the {BOWJON air injection deep well

water pump}

 Wind powered and does not have to be over the well.

It can be up to 1/4 mile away to get the best wind.

later

elvin

[Taylorwindpump]

I own a small ranching operation in west Texas and haul livestock. My sideline business is updating traditional windmills to low cost,low maintenance airlift systems that continue to use the wind & utilize the old wind mill tower while maintaining the "legend of the plains" look. Sorry for the obvious sales pitch, but you're in my neck of the woods & I do not advertize or venture farther than helping my neighbors. My cell 806-543-9826, I'll try to help like Otherpower.com has helped me.